https://lunarpedia.org/api.php?action=feedcontributions&user=Silverwurm&feedformat=atomLunarpedia - User contributions [en]2024-03-29T01:34:13ZUser contributionsMediaWiki 1.34.2https://lunarpedia.org/index.php?title=Ilmenite_Reduction&diff=16748Ilmenite Reduction2011-10-27T06:15:14Z<p>Silverwurm: Undo revision 16746 by 109.230.216.225 (talk) Removing vandalism</p>
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<div>== Introduction ==<br />
[[Reduction|Reducing]] [[ilmenite]] (FeTiO<SUB>3</SUB>) to produce [[oxygen]], [[iron]], and [[titanium]] in a lunar context has produced a number of proposals, many of them specifically aimed at oxygen production. Ilmenite is attractive for this purpose as the iron oxides it contains require less energy to reduce than any other oxide on the lunar surface. For this reason, proposals which have oxygen production as the primary goal usually focus on reduction of the iron content of ilmenite.<br />
<br />
==Hydrogen Reduction==<br />
[[image:ilmen_reduced.GIF|thumb|Lunar Ilmenite reduced at 1050°C by hydrogen for 3 hrs]]<br />
[[Hydrogen]] reduction is one method currently being tested by many Universities. Products of hydrogen reduction are free [[iron]], [[rutile|titanium dioxide (TiO<sub>2</sub>)]], and [[water]], which is [[Water Splitting|split]] to recover the hydrogen and produce [[oxygen]].<br />
<br />
The basic process is to separate ilmenite from lunar soil, crush it to a fine powder to maximize the surface area, and then heat it in an enclosed reaction vessel in the presence of hydrogen gas. The steam produced in the reaction is then condensed and [[Water Splitting|split]] to produce oxygen and recover the hydrogen. <br />
<br />
This process is best utilized if the plant is sited in a location in which ilmenite composes a high fraction of the soil.<br />
<br />
The reaction sequence is:<br />
*''Reduction'': FeTiO<SUB>3</SUB>+H<SUB>2</SUB> ---->Fe+TiO<SUB>2</SUB>+H<SUB>2</SUB>O<br />
*''Water Splitting'': 2H<SUB>2</SUB>O ---->2 H<SUB>2</SUB>+ O<SUB>2</SUB> <br />
*''Net Reaction'': 2FeTiO<SUB>3</SUB>----> 2Fe+2TiO<SUB>2</SUB>+ O<SUB>2</SUB><br />
<br />
The iron produced in the process could be separated out by [[Carbonyl process| carbonyl extraction]], or by grinding the result again and using a magnet. The [[rutile|titanium dioxide]] could also be further [[Lunar Titanium Production|reduced to produce metallic titanium and additional oxygen]].<br />
<br />
==Carbothermal Reduction==<br />
<br />
Oxygen can be retrieved from [[Ilmenite|Ilmenite (FeTiO<sub>3</sub>)]] and [[Rutile|Rutile (TiO<sub>2</sub>)]] by means of carbothermal reduction. In experiments, powdered [[carbon]] and powdered ilmenite/rutile were evenly mixed and then heated to 1500 degrees Celsius. The end products of this reaction are Oxygen and a high strength Ceramic-metal composite (Cermet) of [[iron|Iron (Fe)]] and Titanium Carbide (TiC) which has high chemical stability. The amount of reinforcing TiC ceramic in the matrix can be controlled via the amount of rutile and carbon used<ref>http://www.mtec.or.th/th/seminar/msativ/pdf/CP12.pdf</ref>. While this method provides a means of retrieving all of the oxygen from ilmenite/rutile and a potential for producing reinforced, high performance and wear components and cutting tools from lunar regolith, it is at the cost of highly valuable carbon needed for biological processes.<br />
<br />
Stoichiometry for this reaction:<br />
<BR/><BR/><br />
''Ilmenite'':<BR/><br />
FeTiO<sub>3</sub> + 4C ---->Fe + TiC + 3CO<br />
<BR/><BR/><br />
''Ilmenite and Rutile'':<BR/><br />
FeTiO<sub>3</sub> + nTiO<sub>2</sub> + (4+3n)C ---->Fe + (1+n)TiC + (3+2n)CO<br />
<BR>Where n represents the number of TiO<sub>2</sub> molecules<br />
<br />
===Reduction with CO===<br />
This reaction is based on a fluidized bed scheme which is similar to large scale proposals for Hydrogen Reduction. The product of CO reduction of Ilmenite is [[Carbon Dioxide|Carbon Dioxide (CO<sub>2</sub>)]], which is [[Lunar Carbon Production#Direct CO2 Electrolysis|reduced]] to [[Carbon Monoxide|CO]] and [[oxygen]]. The [[Carbon Monoxide|CO]] is recirculated, and the oxygen stored.<ref>http://www.uapress.arizona.edu/onlinebks/ResourcesNearEarthSpace/resources04.pdf page 9</ref>. The presence of solar wind implanted carbon in the regolith will allow the recovery of additional carbon if recycling efficiency is sufficiently great, though a method for dealing with evolved methane (CH<sub>4</sub>, from hydrogen present in the regolith) would be required. The CO reduction of ilmenite is slower than the H<sub>2</sub> process, but by less than an order of magnitude for any given temperature.<br />
<br />
The reaction sequence is:<br />
<BR/><BR/><br />
''Reduction'':<BR/><br />
FeTiO<sub>3</sub> + CO ---->Fe + TiO<sub>2</sub> + CO<sub>2</sub><br />
<BR/><br />
''Endothermic cracking'':<BR/><br />
2CO<sub>2</sub> ----> 2CO + O<sub>2</sub><br />
<BR/><br />
''Net Reaction'': <BR/><br />
2FeTiO<sub>3</sub> + 2CO ---->2Fe + 2TiO<sub>2</sub> + 2CO + O<sub>2</sub><br />
<BR/><br />
<br />
==Methane Reduction==<br />
{| cellpadding="10" style="border-style:none;border-width:0px"<br />
| style="border-style:dashed; border-width:1px; border-color:#36648B; background:#F0F8FF;" | '''Please note: Methane Reduction'''<br><br />
This section is a placeholder for work currently in progress.<br>-- [[User:Jarogers2001|Jarogers2001]] 22:59, 31 May 2008 (UTC)<br />
|}<br />
==Li or Na Reduction==<br />
==Plasma Reduction==<br />
<br />
== Electrolytic Reduction ==<br />
see [[FFC Cambridge Process]]<br />
<br />
<br />
== References ==<br />
<references/><br />
<br />
== Related Pages ==<br />
*[[Lunar Titanium Production]]<br />
<br />
==External Links==<br />
*ISRU on the Moon. by Larry Taylor [http://www.lpi.usra.edu/lunar_knowledge/LTaylor.pdf http://www.lpi.usra.edu/lunar_knowledge/LTaylor.pdf]<br />
*Extraction Techniques-Oxygen. G. L. Kulcinski, February 18, 2004 [http://fti.neep.wisc.edu/neep533/SPRING2004/lecture13.pdf http://fti.neep.wisc.edu/neep533/SPRING2004/lecture13.pdf]<br />
*Processing Lunar Soils for Oxygen and Other Materials. Knudsen & Gibson [http://nss.org/settlement/nasa/spaceresvol3/plsoom1.htm http://nss.org/settlement/nasa/spaceresvol3/plsoom1.htm]<br />
*[http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/DOCS/EIC048.HTML Lunar Oxygen Production - A Maturing Technology]<br />
*[http://www.mtec.or.th/th/seminar/msativ/pdf/CP12.pdf The Effect of TiO2 on Synthesizing Fe-TiC Composites]<br />
*[http://www.nss.org/settlement/spaceresources/resources2.html Resources of Near-Earth Space. Univ. of Arizona Press]<br />
<BR/><BR/><BR/><br />
<br />
<br />
<br />
[[Category:Air Supply]]<br />
[[Category:Chemistry]]<br />
[[Category:ISRU]]<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Manganese&diff=16684Manganese2011-10-04T23:45:21Z<p>Silverwurm: </p>
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<div>{{Element |<br />
name=Manganese |<br />
symbol=Mn |<br />
available=available |<br />
need= |<br />
number=25 |<br />
mass=54.938049 |<br />
group=7 |<br />
period=4 |<br />
phase=Solid |<br />
series=Transition Metals |<br />
density=7.21 g/cm3 |<br />
melts=1519K,<BR/>1246°C,<BR/>2275°F |<br />
boils=2334K,<BR/>2061°C,<BR/>3742°F |<br />
isotopes=55 |<br />
prior=[[Chromium|<FONT color="#7F7FFF">Cr</FONT>]] |<br />
next=[[Iron|<FONT color="#7F7FFF">Fe</FONT>]] |<br />
above=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
aprior=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
anext=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
below=[[Technetium|<FONT color="#7F7FFF">Tc</FONT>]] |<br />
bprior=[[Molybdenum|<FONT color="#7F7FFF">Mo</FONT>]] |<br />
bnext=[[Ruthenium|<FONT color="#7F7FFF">Ru</FONT>]] |<br />
radius=140 |<br />
bohr=161 |<br />
covalent=139 |<br />
vdwr= |<br />
irad=(+2) 67 |<br />
ipot=7.43 |<br />
econfig=1s<sup>2</sup> <br/>2s<sup>2</sup> 2p<sup>6</sup> <br/>3s<sup>2</sup> 3p<sup>6</sup> 3d<sup>5</sup> <br/>4s<sup>2</sup> |<br />
eshell=2, 8, 13, 2 |<br />
enega=1.55 |<br />
eaffin=Unstable anion |<br />
oxstat=7, 6, 4, '''2''', 3 |<br />
magn=Nonmagnetic |<br />
cryst=Body centered cubic |<br />
}}<br />
'''Manganese''' is a Transition Metal in group 7.<br />
It has a Body centered cubic crystalline structure.<br />
This element has a stable isotope of 55<br />
<br />
<br />
== Lunar Availability ==<br />
Lunar manganese is found substituting for iron in various oxides, in approximately a 1:70 ratio <ref>Washington University in Saint Louis, Department of Earth and Planetary Sciences [http://meteorites.wustl.edu/lunar/howdoweknow.htm How Do We Know That It’s a Rock From the Moon?]</ref>.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
<br />
<br />
{{Autostub}}<br />
[[Category:Nonmagnetic Elements]]<br />
[[Category:Solids]]<br />
[[Category:Transition Metals ]]<br />
<br />
<!-- Generated by a gamma candidate version of Autostub2 (Test 9) --></div>Silverwurmhttps://lunarpedia.org/index.php?title=Ilmenite&diff=16630Ilmenite2011-09-22T20:06:44Z<p>Silverwurm: added link to beneficiation page</p>
<hr />
<div>== Introduction ==<br />
<br />
'''Ilmenite''' ([[Iron|Fe]][[Titanium|Ti]]O<SUB>3</SUB>, also known as Iron titanate, or [[Iron]] [[Titanium]] oxide) is a naturally occurring titanium and iron ore. It is named for the location where it was discovered, Ilmen Lake in the Ural Mountains of Russia. Ilmenite is currently the most important ore of Titanium for terrestrial production. It is reasonably abundant on the Luna, the greatest concentrations being found in the lunar maria.<br />
<br />
<br />
== Lunar Extraction and Use ==<br />
(see also: [[Ilmenite Reduction]])<br />
<br />
Ilmenite is weakly magnetic, and can be removed from lunar regolith by [[Beneficiation|magnetic beneficiation]]. This property allows for the relatively easy extraction of Ilmenite, even from areas where it is not as abundant.<br />
<br />
Ilmenite has been proposed as a feedstock for lunar [[Lunar Titanium Production|titanium]] and [[iron]] production. In addition, the iron oxides present in the Ilmenite require the least energy to reduce of any oxide found on Luna. Because of this property, together with the ease of extraction from lunar sources, ilmenite has been proposed as a prime material for production of lunar [[Oxygen]].<br />
<br />
Crystallized Ilmenite is a semiconductor with a bandgap of 2.54 volts. Ilmenite photovoltaic cells would have a greater conversion efficiency then silicon or gallium arsenide in unfiltered solar radiation. Also, they should withstand higher temperature with less radiation damage.<br />
<br />
==External Links==<br />
<!-- Detailed information on the lunar oxygen extraction from Ilmenites process can be found at: --><br />
*Anthony, J. Colozza, Wayne A. Wong, [http://gltrs.grc.nasa.gov/reports/2006/TM-2006-214360.pdf Evaluation of a Stirling Solar Dynamic System for Lunar Oxygen Production], NASA/TM -- 2006-214360 <br />
*[http://mineral.galleries.com/minerals/oxides/ilmenite/ilmenite.htm Amethyst Galleries' Mineral Gallery]<br />
*[http://en.wikipedia.org/wiki/Ilmenite http://en.wikipedia.org/wiki/Ilmenite Wikipedia article on Ilmenite]<br />
*[http://webmineral.com/data/Ilmenite.shtml e-Rocks.com Ilmenite Mineral Data]<br />
*[http://www.mindat.org/min-2013.html Mindat.org Ilmenite mineral information and data]<br />
*Space Solar News Vol. 4 No. 6, [http://www.outofthecradle.net/WordPress/wp-content/uploads/srn_v4n06.pdf Lunar Ilmenite for Solar Cells]<br />
[[Category:Selenology]] <br />
[[Category:Chemistry]]<br />
[[Category:Minerals]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Chromite&diff=16629Chromite2011-09-22T20:03:51Z<p>Silverwurm: changed inline link to reference</p>
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<div>{{chem Stub}}<BR/><BR/><BR/><br />
{|<br />
| Chemical Name: || [[Iron]] [[Chromium]] Oxide ||<br />
|-<br />
| Chemical Formula: || FeCr<sub>2</sub>O<sub>4</sub> ||<br />
|-<br />
|}<br />
This is the most important ore of [[chromium]], the element from which chromite derives its name. Chromite is found in ultra-mafic rocks amd forms in deep ultra-mafic magmas where it is one of the first minerals to crystallize. While the magma slowly cools, chromite crystals "snow" into concentrated areas near the bottom due to their higher density. Chromite is resistant to the altering effects of high pressures and tempuratures and is used as a refractory component in the bricks and linings of blast furnaces.<BR/><br />
[[Magnesium]] is present in all natural chromites and sometimes replaces the iron to form the much rarer mineral magnesiochromite. All magnesiochromites contain some iron and both minerals form a series between them.<br />
Geologic surveys of the moon have located large deposits of chromite on the Sinus Aestuum, covering an area thousands of square kilometers in size <ref>[http://www.nasa.gov/topics/moonmars/features/moonrock-king_prt.htm NASA Article on Chromite Deposits]</ref>.<br />
<br />
<br />
== References ==<br />
<references/><br />
[[Category:Chemistry]]<br />
[[Category:Selenology]]<br />
[[Category:Minerals]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Beneficiation&diff=16628Beneficiation2011-09-22T20:01:43Z<p>Silverwurm: Page creation</p>
<hr />
<div>__TOC__<br />
== Introduction ==<br />
Beneficiation refers to processes which concentrate desired materials out of collected ore. In a lunar context, the ore proposed is most commonly the finely powdered lunar regolith. Many of processes suggested for lunar use are adaptations of those used terrestrially.<br />
<br />
== Magnetic Beneficiation ==<br />
Materials that are at least weakly magnetic can be concentrated by use of a magnetic field. This is most commonly accomplished terrestrially by use of a drum-shaped electromagnet, which rotates as the input material is poured over it. Magnetic materials stick to the drum and are scraped off the other side, while the non-magnetic materials fall straight down.<br />
<br />
Another method is to let the material fall through a chamber with magnet one side. Magnetic materials will be deflected by different amounts depending on the how magnetic they are, falling into multiple bins below. The low gravity (1/6 that of earth) and vacuum environment found on the moon greatly enhance this process. Low gravity allows even small chambers to provide large separation, as the material falls much more slowly then on earth. Lack of atmosphere eliminates turbulence that can remix the separated components, as well as removing air resistance, making each grain fall at the same rate regardless of its density or size.<br />
<br />
Minerals which can be magnetically separated on the lunar surface include meteoric [[iron]] particles (containing [[iron]] and [[nickel]]), iron oxides, [[ilmenite]], and [[chromite]], among others.<br />
<br />
== Electrostatic Beneficiation ==<br />
Electrostatic beneficiation is similar to magnetic beneficiation, except that instead of using magnetic attraction, electrostatic attraction/repulsion is used. The material gathered is electrically charged by either running it over a charged surface, or using an electron beam. This charged material is then separated using a charged plate, either as a drum or in a gravitationally assisted separation chamber, as is done in magnetic beneficiation.<br />
<br />
This process has the advantage of being useable on a wider range of minerals than by using magnets, as all minerals have some propensity to absorb electric charge, and most lunar materials have very different values from each other.<br />
<br />
Electrostatic beneficiation could be utilized in conjunction with magnetic beneficiation, the magnetic materials removed first, followed by electrostatic separation of any additional minerals desired.<br />
<br />
== External Links ==<br />
[http://www.permanent.com/i-minera.htm Mineral Separation on PERMANENT]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16611Roof Support2011-09-18T02:37:25Z<p>Silverwurm: /* Safety considerations */</p>
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<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitants, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]). Most of the thickness called for in this blanket is to protect against cosmic radiation.<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver, a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitational acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. Even if a structure was only pressurized to equal the peak of mount everest, it would be able to support sea level radiation shielding and still have a net outward force. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around one sixth of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure balance would be quite different.<br />
<br />
As a result, a lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces of pressure are greater. A lunar habitat could therefore be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining standard atmospheric pressure six feet underwater in an emergency, as well as containing twice atmospheric pressure under the same conditions normally. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, designing it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. Multiple air bladders around the outsize, also compartmentalized, would also aid in reducing the chance of a blowout. An additional safety measure that could be installed is for each section of the habitat to have its own backup gas tank, which would open in case of a pressure loss, feeding the leak until an patch job / evacuation could be achieved. Since the minimum pressure that needs to be maintained is quite low (as discussed previously), this approach could be utilized with a modestly sized backup tank.<br />
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{{Hazards}}<br />
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[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Architecture&diff=16610Lunar Architecture2011-09-18T02:36:28Z<p>Silverwurm: /* Atmospheric Control */ added roof support link</p>
<hr />
<div>__TOC__<br />
<br />
== Introduction ==<br />
The architecture used on Luna will be quite different from that used in terrestrial applications. Lower gravity, high vacuum, radiation, meteorites, [[moonquake|moonquakes]], and dust control will all play large parts in the design of lunar structures. Due to this, a large number of architectural designs have been put forward for human rated habitats on Luna.<br />
<br />
== Major Design Criteria ==<br />
<br />
=== Atmosphere ===<br />
(see also [[Lunar Settlement Artificial Atmosphere]], [[Roof Support]])<br />
<br />
Any lunar habitat designed for human use must provide a breathable atmosphere and maintain proper carbon dioxide, temperature, and humidity levels. There are a number of methods proposed for achieving this, as well as number of proposals for suitable gas mixtures and pressures, as well as designs for containing a pressurized environment in the lunar vacuum.<br />
<br />
=== Thermal Protection ===<br />
The lack of an atmosphere on the moon, together with the extreme duration of the lunar day/night cycle, leads to large temperature extremes. A lunar habitat would need to provide a reasonably constant temperature inside.<br />
<br />
The most commonly proposed solution to this problem is a blanket of lunar regolith piled over the habitat. Lunar regolith has extremely low thermal conductivity, and as little as a few inches would protect the habitat from any temperature swings that would be experienced outside<ref name='Lindsey'>Lindsey, Nancy J. [http://www.rcktmom.com/njlworks/LunarRegolithPprenvi2.html Lunar Station Protection: Lunar Regolith Shielding]. International Lunar Conference 2003</ref>. This solution has an advantage in that lunar regolith is readily available anywhere on the moons surface. The downside is that moving a sufficient amount of regolith to cover a lunar structure would require construction equipment on site, which may not be available for an initial lunar base attempt.<br />
<br />
More conventional insulation could be used in this case as well. Due to the vacuum conditions on the moons surface, a reflective coating applied to the surface of the habitat would provide reasonably good thermal protection, functioning in a similar manner to a thermos. This coating would reflect solar radiation during the day, and preventing radiation of internal heat at night. Multiple reflective baffles installed at the surface would increase the effect. To date, this approach has been utilized on all lunar missions, all of which took place during the lunar day and near the equator.<br />
<br />
Even if the insulation was sufficient to block out the temperature variations, some additional cooling would be required, as energy would be continuously be generated within the habitat from electrical equipment and the metabolic processes of the inhabitants. Insulation sufficient to block out heat from outside would, on the same token, keep heat inside. A series of external radiators, suitably placed so as to be out of the sun during the day, could provide the necessary cooling.<br />
<br />
=== Meteorites ===<br />
A lunar habitat would need to be protected from meteorite impacts. This requirement is similar to the requirements already in place on orbital structures such as the ISS. One significant difference is that orbital structures have a certain amount of maneuvering capability to dodge incoming debris, while a lunar habitat does not. As such lunar structures have more stringent requirements than orbital structures for impact protection.<br />
<br />
The solution to this problem most commonly suggested is the same as for thermal protection, namely, a blanket of lunar regolith. This blanket would need to be thicker than what is required for thermal protection, though a thickness of less than half a meter is considered to be sufficient<ref name='Lindsey'> </ref>. This again carries the requirement of having construction equipment on site.<br />
<br />
Other shielding technologies could be utilized to provide sufficient meteorite protection. Inflatable spacecraft designs in particular show promise in this regard. Bigelow aerospace is developing a line of these structures, a derivative of the cancelled NASA TransHab project. Bigelow has already flown two prototypes of this technology, and intends to construct a privatelly owned space station with them, as well as an eventual moonbase. The company claims that the meteorite shielding material built into its modules is sufficient for this purpose.<br />
<br />
=== Radiation ===<br />
One of the more difficult problems facing design of a lunar habitat is protection from solar and cosmic radiation. The moon, being outside the earths magnetic field, receives this radiation directly. Of particular importance is the effect of solar storms, a single one of which would provide sufficient radiation to kill an unprotected person.<br />
<br />
The regolith blanket proposed as protection from thermal and meteorite hazards could also serve the third function of radiation protection, given sufficient thickness. How thick this shield would need to be is a matter of some debate, as the exact level of safe radiation is not entirely agreed upon. To reduce the radiation levels received to current NASA standards for its astronauts, a thickness of 1-2 meters appears to be sufficient<ref name="Lindsey"> </ref>. If earth-like levels are desired, then 3-5 meters would likely be needed. The exact thickness is not precisely known, due to the differences between cosmic radiation and the nuclear radiation most shielding science is designed to protect against, and most likely will remain an educated guess until a more in-depth field study is made.<br />
<br />
If equipment for moving a sufficient amount of lunar regolith is not available on site (an early base construction attempt for example), providing sufficient shielding is difficult matter. One option is to site the base in of the the permanently shaded polar craters, where solar storms would not reach. Another is to provide a "storm cellar" of sorts, a small room in the habitat which is heavily shielded against radiation, which the crew could retreat into in case of a solar storm. As this room would only need to be big enough to hold the crew until the radiation levels dropped back to normal, its construction and shipping to the base site would be much simpler than shielding the entire habitat, which could make it a viable solution for an early base attempt.<br />
<br />
=== Moonquakes ===<br />
(see main article: [[Moonquake]])<br />
<br />
Moonquakes are moderately powerful (by earth standards) seismic events which can last for over ten minutes. Habitats placed in areas where moonquakes occur will need to be sufficiently strong/flexible to withstand the shaking without buckling or leaking atmosphere.<br />
<br />
== Proposed Designs ==<br />
;[[Architecture as Mole Hills]]: The living space could be inflated structures buried in trenches.<br />
<br />
;[[Architecture as Tent City]]: We could use tents to protect inflated living space.<br />
<br />
;[[Architecture in Field Stone]]: The loose rocks of the Moon could provide the needed thermal and radiation protection.<br />
<br />
==See Also==<br />
*[[Meteor Hazards]]<br />
*[[Radiation Problem]]<br />
*[[Roof Support]]<br />
*[[Power for Settlements]]<br />
*[[Site Selection]]<br />
*[[Slopes]]<br />
<br />
==References==<br />
<references/><br />
<br />
[[Category:Architecture]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16595In-Situ Propellant Production2011-09-16T02:32:13Z<p>Silverwurm: /* Sulfur */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. The specific impulse of silane is slightly less than methane, and would use slightly less hydrogen for a given launch weight.<br />
<br />
Silane holds an advantage over methane as silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, in what is sometimes referred to as a "Brimstone Rocket". Sulfur melts at about 115 °C, which could be easily achieved by preheating the fuel tank before launch. Burning this molten sulfur with liquid oxygen would produce sulfur dioxide as exhaust, with a specific impulse of around 285 seconds. Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon, some mare soils containing as much as .27% by weight.<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>. In addition, unlike [[hydrogen]] and [[carbon]], [[sulfur]] compounds may be extractable by magnetic benefication rather than heating the regolith, greatly reducing both the complexity and energy requirements of gathering them.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Sulfur&diff=16594Sulfur2011-09-16T02:24:02Z<p>Silverwurm: added discussion of troilite</p>
<hr />
<div>{{Element |<br />
name=Sulfur |<br />
symbol=S |<br />
available=good |<br />
need= |<br />
number=16 |<br />
mass=32.066 |<br />
group=16 |<br />
period=3 |<br />
phase=Solid |<br />
series=Non-metals |<br />
density=(alpha) 2.07 g/cm3<BR/><br />
(beta) 1.96 g/cm3<BR/><br />
(gamma) 1.92 g/cm3 |<br />
melts=388.36K,<BR/>115.21°C,<BR/>239.38°F |<br />
boils=717.8K,<BR/>444.6°C,<BR/>832.3°F |<br />
isotopes=32<BR/>33<BR/>34<BR/>36 |<br />
prior=[[Phosphorus|<FONT color="#7F7FFF">P</FONT>]] |<br />
next=[[Chlorine|<FONT color="#7F7FFF">Cl</FONT>]] |<br />
above=[[Oxygen|<FONT color="#7F7FFF">O</FONT>]] |<br />
aprior=[[Nitrogen|<FONT color="#7F7FFF">N</FONT>]] |<br />
anext=[[Fluorine|<FONT color="#7F7FFF">F</FONT>]] |<br />
below=[[Selenium|<FONT color="#7F7FFF">Se</FONT>]] |<br />
bprior=[[Arsenic|<FONT color="#7F7FFF">As</FONT>]] |<br />
bnext=[[Bromine|<FONT color="#7F7FFF">Br</FONT>]] |<br />
radius=100 |<br />
bohr=88 |<br />
covalent=102 |<br />
vdwr=180 |<br />
irad=(-2) 184 |<br />
ipot=10.36 |<br />
econfig=1s<sup>2</sup> <br/>2s<sup>2</sup> 2p<sup>6</sup> <br/>3s<sup>2</sup> 3p<sup>4</sup> |<br />
eshell=2, 8, 6 |<br />
enega=2.58 |<br />
eaffin=2.08 |<br />
oxstat=+/-2, 4, '''6''' |<br />
magn=? |<br />
cryst=Orthorhombic |<br />
}}<br />
'''Sulfur''' is a Non-metal in group 16.<br />
It has a Orthorhombic crystalline structure.<br />
This element has 4 stable isotopes: 32, 33, 34, and 36. <br />
<BR/><BR/><br />
<br />
Sulfur is availible in lunar soil in significant quantities, principally in the form of troilite ([[Iron|Fe]]S), comprising around 1% of the lunar crust<ref name="wikisulfur">[http://en.wikipedia.org/wiki/Troilite Sulfur on Wikipedia]</ref>. Magnetic benefication may be able to concentrate troilite out of the lunar regolith, as it is weakly magnetic when the crystal structure is incomplete, as well as being commonly associated with native iron<ref name="wikisulfur"> </ref>. In addition, concentrated veins of troilite have been found in some lunar rocks, and it has been suggested that larger deposits of the mineral may exist<ref>I. Casanova. [http://www.lpi.usra.edu/meetings/lpsc97/pdf/1483.PDF Feasibility and Applications of Sulfur Concrete for Lunar Base Development: A Preliminary Study.] Lunar and Planetary Science XXVIII</ref>.<br />
<br />
Several uses have been proposed for lunar sulfur, including [[In-Situ Propellant Production|rocket propellant]], production of sulfuric acid for industrial processes, lunar concrete, and sealants<ref>[http://www.nss.org/settlement/moon/library/LB2-509-UsesOfLunarSulfur.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:Solids]]<br />
[[Category:Non-metals ]]<br />
<br />
<!-- Generated by a gamma candidate version of Autostub2 (Test 9) --></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Aluminum_Production&diff=16583Lunar Aluminum Production2011-09-09T18:28:27Z<p>Silverwurm: /* Carbothermal Reduction */</p>
<hr />
<div>Since Luna lacks any known deposits of bauxite, the ore most commonly used on earth for aluminum production, [[anorthite]] (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>) is most commonly proposed as a lunar substitute.<ref>http://www.permanent.com/l-minera.htm#aluminum</ref> [[Anorthite]] could be separated from the lunar highland material [[Anorthosite]] with mechanical methods. It could then be reduced through various chemical and electrochemical methods to produce [[aluminum]].<br />
<br />
<br />
== Anorthite Production ==<br />
<br />
The [[Anorthosite]] which makes up the Lunar highlands is a mix of [[Plagioclase]]s, [[Olivine]]s, and [[Pyroxene]]s. To separate the [[anorthite]], [[anorthosite]] must be ground. Then, magnetic separation could leave the non-magnetic anorthite.<br />
<br />
The magnetic materials ([[Ilmenite]] and iron oxide) could be stored for production of [[titanium]], [[iron]], and [[oxygen]].<br />
<br />
== Anorthite Refinement ==<br />
<br />
===Direct Reduction===<br />
Main Article: [[FFC Cambridge Process#Aluminum/Silicon/Calcium Production from Anorthite|FFC Cambridge Process]]<br />
<br />
[[Anorthite]] could be directly reduced to its component metals using the [[FFC Cambridge Process]]. The [[Anorthite]] is pressed/sintered into a cathode, which is placed in a bath of molten calcium chloride and electrolyzed. The oxygen is stripped out, leaving behind [[Aluminum]], [[Calcium]], and [[Silicon]].<br />
<br />
This process has the advantage of inherent simplicity, as well as having only one component to recycle, the calcium chloride, which does not react chemically with the inputs, making recovery much simpler. In addition, this process runs at lower temperatures (900º-1100º C) than many other electrolysis procedures, and inert(non-consumable) anodes have been successfully demonstrated with it<ref>http://www.lpi.usra.edu/meetings/roundtable2006/pdf/tripuraneni.pdf</ref>. On the downside, energy must be expended to split all the components of the [[Anorthite]], not just the [[aluminum]]. Splitting the silicon and calcium adds a significant amount of extra energy to the process, as both of them are strong reducers. However, if the silicon and calcium byproducts were needed for other purposes (calcium is a good [[Electrical Conductors|electrical conductor]], and silicon could be used for solar panels or [[In-Situ Propellant Production|rocket fuel]]), this extra energy cost may not be an issue.<br />
<br />
=== Alumina Production ===<br />
<br />
Many processes used on earth or proposed for Lunar use require [[alumina]] ([[Aluminum|Al]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) as an input. On Earth, alumina is produced from bauxite through the Bayer process. As this process is not feasible using Anorthite, another method must be utilized.<br />
<br />
====Vacuum Distillation====<br />
<br />
[[Alumina]] could be produced from Anorthite by boiling out the impurities between 1500 ºC - 2000 ºC under vacuum conditions. The resulting material would be calcium aluminate ([[Ca]][[Al]][[O]]<sub>4</sub>). Raising the temperature further could cause [[alumina]] to volatilize as well. <ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Sulfuric Acid Leaching====<br />
<br />
Another method is to produce calcium aluminate as outlined previously, which is then leached in sulfuric acid, resulting in the following reaction:<br />
<br />
[[Ca]][[Al]]<sub>2</sub>[[O]]<sub>4</sub> + [[Sulfuric Acid |4H<sub>2</sub>SO<sub>4</sub>]] ==> [[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub> + 4[[water |H<sub>2</sub>O]]<br />
<br />
Aluminium sulfate in hexadecahydrate form ([[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) is then separated from calcium sulphate ([[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) by filtering and from water by evaporation (and then recovered).<br />
<br />
Finally Alumina is obtained by roasting the aluminum sulfate releasing [[S]]<sub>2</sub>.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Hydrochloric Acid Leaching====<br />
Another option is to react [[Anorthite]] with hydrochloric acid, which results in following reaction:<br />
<br />
: [[Ca]][[Al]]<sub>2</sub>[[Si]]<sub>2</sub>[[O]]<sub>8</sub> + 8 [[H]][[Cl]] + 2 [[H]]<sub>2</sub>[[O]]==> [[Ca]][[Cl]]<sub>2</sub> + 2 [[Al]][[Cl]]<sub>3</sub>.6 [[H]]<sub>2</sub>[[O]] + 2 [[Si]][[O]]<sub>2</sub><br />
<br />
The calcium chloride and hydrated aluminum chloride dissolve in the solution and are removed. They are then precipitated out of solution, dried, and heated under partial vacuum until the calcium chloride evaporates out of the mix. Temperatures of this range will cause the hydrated aluminum chloride to become [[alumina]], releasing water and hydrogen chloride in the process:<br />
<br />
: 2 AlCl<sub>3</sub>.6 H<sub>2</sub>O ==> Al<sub>2</sub>O<sub>3</sub> + 6 HCl + 3 H<sub>2</sub>O<br />
<br />
The water and hydrogen chloride are separated from the calcium chloride and fed back into the system. The calcium chloride is then electrolyzed into metallic calcium and chlorine. A portion of the recovered water is then [[Water Splitting|split]] into hydrogen and oxygen. The hydrogen component is reacted with the evolved chlorine to produce hydrogen chloride, which is then fed back into the main system.<br />
<br />
=== Direct Calcium Aluminate / Alumina Reduction ===<br />
<br />
Calcium Aluminate (see above for production) could be simply melted and electrolyzed directly, producing aluminum and calcium oxide.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref> This has two advantages. First, it requires no imported reagents, and second, only the aluminum is split, reducing the amount of energy needed. The disadvantage is that temperatures of approximately 1600 ºC are required, making electrode material of prime concern. Carbon electrodes could be utilized at those temperatures, but the anode would continually wear away as oxygen was produced around it, creating carbon monoxide. The carbon would need to be [[Lunar Carbon Production|recovered]] and new anodes made from it. This effectively means that a rare reagent is needed, negating the process's first stated advantage. Finding an anode material that would produce oxygen without wearing away at those temperatures could be quite difficult.<br />
<br />
Alumina could also be directly melted and electrolyzed in the same fashion. However, this would require temperatures of approximately 2000 ºC, bringing with it again the issue of electrode material.<br />
<br />
=== Hall-Heroult Process ===<br />
<br />
In the Hall-Heroult process, alumina is dissolved in molten cryolite ([[Sodium]] hexafluoroaluminate, Na<sub>3</sub> AlF<sub>6 </sub>) around 1400 ºC. This mix is electrolyzed to separate two byproducts: [[aluminium]] and [[Carbon Dioxide|CO<sub>2</sub>]]. The carbon comes from the consumption of the carbon anode.<br />
<br />
This procedure is used extensively on earth for aluminum production, and as such has the advantage of being a very mature technology. The biggest issue is the consumption of the anode, which would require the produced carbon monoxide to be captured, [[Lunar Carbon Production|converted back into carbon]], and recast into new anodes; an energy intensive process. It is not known if an inert(non-consumable) anode material can be found that would work under these conditions.<ref>http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process</ref><br />
<br />
=== Subchloride Process ===<br />
<br />
In the subchloride process [[alumina]] is reacted with [[carbon]] and [[chlorine]] to yield [[Al]][[Cl]]<sub>3</sub> and [[Carbon dioxide |CO<sub>2</sub>]]. The [[Al]][[Cl]]<sub>3</sub> is electrolyzed to produce [[aluminum]] while recovering the [[chlorine]]. This has the advantage that conventional [[carbon]] electrodes can be used continuously, as the produced [[chlorine]] does not react with them. However, the [[Carbon dioxide |CO<sub>2</sub>]] byproduct must be [[Lunar Carbon Production|recycled]], adding extra complexity and energy requirements to the system. This makes it similar to the Hall-Heroult process in difficulty, except for two advantages. First, the recycled carbon can be directly used in powdered form, it does not need to be recast into electrodes. Second, due to the low melting point of [[Al]][[Cl]]<sub>3</sub> (120 ºC), the process does not require significant energy to melt, and is more easily handled. <ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
=== Carbothermal Reduction ===<br />
<br />
Carbon reduction of Alumina is impossible under normal smelting conditions, due to [[aluminum]]s high reduction potential. However, Alumina could be mixed with silica and carbon and melted near 2000 ºC, which would form an aluminium-silicon alloy, as well as CO<sub>2</sub>. This could be separated by cooling the Al-Si mixture to 700 - 1000 ºC and allowing the silicon to solidify and settle out of the melt.<ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
An alternate process involves alumina and carbon processed at high temperatures and low pressure into Al<sub>4</sub>C<sub>3</sub> and carbon monoxide.<ref> [http://en.wikipedia.org/wiki/Aluminium ''Aluminum'' section ''Production and refinement''] </ref><br />
<ref> [http://www.moonminer.com/Lunar_Aluminum.html ''Lunar Aluminum'' at ''Moondust index''] </ref> This breaks down into Aluminum and Carbon between 1900 and 2000 ºC.<ref> [http://en.wikipedia.org/wiki/Aluminum_carbide ''Aluminium carbide'' at ''Wikipedia''] </ref>.<br />
<br />
In either case, CO<sub>2</sub>/CO would have to be recovered and and the [[Lunar Carbon Production|carbon recycled]].<br />
<br />
== See Also ==<br />
<br />
*[[Aluminium]]<br />
*[[Magma Electrolysis]]<br />
*[[ISRU]]<br />
*[[List of Proposed Metal Production Methods]]<br />
<br />
== References ==<br />
<references/><br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Aluminum_Production&diff=16582Lunar Aluminum Production2011-09-09T18:27:26Z<p>Silverwurm: /* Hall-Heroult Process */</p>
<hr />
<div>Since Luna lacks any known deposits of bauxite, the ore most commonly used on earth for aluminum production, [[anorthite]] (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>) is most commonly proposed as a lunar substitute.<ref>http://www.permanent.com/l-minera.htm#aluminum</ref> [[Anorthite]] could be separated from the lunar highland material [[Anorthosite]] with mechanical methods. It could then be reduced through various chemical and electrochemical methods to produce [[aluminum]].<br />
<br />
<br />
== Anorthite Production ==<br />
<br />
The [[Anorthosite]] which makes up the Lunar highlands is a mix of [[Plagioclase]]s, [[Olivine]]s, and [[Pyroxene]]s. To separate the [[anorthite]], [[anorthosite]] must be ground. Then, magnetic separation could leave the non-magnetic anorthite.<br />
<br />
The magnetic materials ([[Ilmenite]] and iron oxide) could be stored for production of [[titanium]], [[iron]], and [[oxygen]].<br />
<br />
== Anorthite Refinement ==<br />
<br />
===Direct Reduction===<br />
Main Article: [[FFC Cambridge Process#Aluminum/Silicon/Calcium Production from Anorthite|FFC Cambridge Process]]<br />
<br />
[[Anorthite]] could be directly reduced to its component metals using the [[FFC Cambridge Process]]. The [[Anorthite]] is pressed/sintered into a cathode, which is placed in a bath of molten calcium chloride and electrolyzed. The oxygen is stripped out, leaving behind [[Aluminum]], [[Calcium]], and [[Silicon]].<br />
<br />
This process has the advantage of inherent simplicity, as well as having only one component to recycle, the calcium chloride, which does not react chemically with the inputs, making recovery much simpler. In addition, this process runs at lower temperatures (900º-1100º C) than many other electrolysis procedures, and inert(non-consumable) anodes have been successfully demonstrated with it<ref>http://www.lpi.usra.edu/meetings/roundtable2006/pdf/tripuraneni.pdf</ref>. On the downside, energy must be expended to split all the components of the [[Anorthite]], not just the [[aluminum]]. Splitting the silicon and calcium adds a significant amount of extra energy to the process, as both of them are strong reducers. However, if the silicon and calcium byproducts were needed for other purposes (calcium is a good [[Electrical Conductors|electrical conductor]], and silicon could be used for solar panels or [[In-Situ Propellant Production|rocket fuel]]), this extra energy cost may not be an issue.<br />
<br />
=== Alumina Production ===<br />
<br />
Many processes used on earth or proposed for Lunar use require [[alumina]] ([[Aluminum|Al]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) as an input. On Earth, alumina is produced from bauxite through the Bayer process. As this process is not feasible using Anorthite, another method must be utilized.<br />
<br />
====Vacuum Distillation====<br />
<br />
[[Alumina]] could be produced from Anorthite by boiling out the impurities between 1500 ºC - 2000 ºC under vacuum conditions. The resulting material would be calcium aluminate ([[Ca]][[Al]][[O]]<sub>4</sub>). Raising the temperature further could cause [[alumina]] to volatilize as well. <ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Sulfuric Acid Leaching====<br />
<br />
Another method is to produce calcium aluminate as outlined previously, which is then leached in sulfuric acid, resulting in the following reaction:<br />
<br />
[[Ca]][[Al]]<sub>2</sub>[[O]]<sub>4</sub> + [[Sulfuric Acid |4H<sub>2</sub>SO<sub>4</sub>]] ==> [[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub> + 4[[water |H<sub>2</sub>O]]<br />
<br />
Aluminium sulfate in hexadecahydrate form ([[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) is then separated from calcium sulphate ([[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) by filtering and from water by evaporation (and then recovered).<br />
<br />
Finally Alumina is obtained by roasting the aluminum sulfate releasing [[S]]<sub>2</sub>.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Hydrochloric Acid Leaching====<br />
Another option is to react [[Anorthite]] with hydrochloric acid, which results in following reaction:<br />
<br />
: [[Ca]][[Al]]<sub>2</sub>[[Si]]<sub>2</sub>[[O]]<sub>8</sub> + 8 [[H]][[Cl]] + 2 [[H]]<sub>2</sub>[[O]]==> [[Ca]][[Cl]]<sub>2</sub> + 2 [[Al]][[Cl]]<sub>3</sub>.6 [[H]]<sub>2</sub>[[O]] + 2 [[Si]][[O]]<sub>2</sub><br />
<br />
The calcium chloride and hydrated aluminum chloride dissolve in the solution and are removed. They are then precipitated out of solution, dried, and heated under partial vacuum until the calcium chloride evaporates out of the mix. Temperatures of this range will cause the hydrated aluminum chloride to become [[alumina]], releasing water and hydrogen chloride in the process:<br />
<br />
: 2 AlCl<sub>3</sub>.6 H<sub>2</sub>O ==> Al<sub>2</sub>O<sub>3</sub> + 6 HCl + 3 H<sub>2</sub>O<br />
<br />
The water and hydrogen chloride are separated from the calcium chloride and fed back into the system. The calcium chloride is then electrolyzed into metallic calcium and chlorine. A portion of the recovered water is then [[Water Splitting|split]] into hydrogen and oxygen. The hydrogen component is reacted with the evolved chlorine to produce hydrogen chloride, which is then fed back into the main system.<br />
<br />
=== Direct Calcium Aluminate / Alumina Reduction ===<br />
<br />
Calcium Aluminate (see above for production) could be simply melted and electrolyzed directly, producing aluminum and calcium oxide.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref> This has two advantages. First, it requires no imported reagents, and second, only the aluminum is split, reducing the amount of energy needed. The disadvantage is that temperatures of approximately 1600 ºC are required, making electrode material of prime concern. Carbon electrodes could be utilized at those temperatures, but the anode would continually wear away as oxygen was produced around it, creating carbon monoxide. The carbon would need to be [[Lunar Carbon Production|recovered]] and new anodes made from it. This effectively means that a rare reagent is needed, negating the process's first stated advantage. Finding an anode material that would produce oxygen without wearing away at those temperatures could be quite difficult.<br />
<br />
Alumina could also be directly melted and electrolyzed in the same fashion. However, this would require temperatures of approximately 2000 ºC, bringing with it again the issue of electrode material.<br />
<br />
=== Hall-Heroult Process ===<br />
<br />
In the Hall-Heroult process, alumina is dissolved in molten cryolite ([[Sodium]] hexafluoroaluminate, Na<sub>3</sub> AlF<sub>6 </sub>) around 1400 ºC. This mix is electrolyzed to separate two byproducts: [[aluminium]] and [[Carbon Dioxide|CO<sub>2</sub>]]. The carbon comes from the consumption of the carbon anode.<br />
<br />
This procedure is used extensively on earth for aluminum production, and as such has the advantage of being a very mature technology. The biggest issue is the consumption of the anode, which would require the produced carbon monoxide to be captured, [[Lunar Carbon Production|converted back into carbon]], and recast into new anodes; an energy intensive process. It is not known if an inert(non-consumable) anode material can be found that would work under these conditions.<ref>http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process</ref><br />
<br />
=== Subchloride Process ===<br />
<br />
In the subchloride process [[alumina]] is reacted with [[carbon]] and [[chlorine]] to yield [[Al]][[Cl]]<sub>3</sub> and [[Carbon dioxide |CO<sub>2</sub>]]. The [[Al]][[Cl]]<sub>3</sub> is electrolyzed to produce [[aluminum]] while recovering the [[chlorine]]. This has the advantage that conventional [[carbon]] electrodes can be used continuously, as the produced [[chlorine]] does not react with them. However, the [[Carbon dioxide |CO<sub>2</sub>]] byproduct must be [[Lunar Carbon Production|recycled]], adding extra complexity and energy requirements to the system. This makes it similar to the Hall-Heroult process in difficulty, except for two advantages. First, the recycled carbon can be directly used in powdered form, it does not need to be recast into electrodes. Second, due to the low melting point of [[Al]][[Cl]]<sub>3</sub> (120 ºC), the process does not require significant energy to melt, and is more easily handled. <ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
=== Carbothermal Reduction ===<br />
<br />
Carbon reduction of Alumina is impossible under normal smelting conditions, due to [[aluminum]]s high reduction potential. However, Alumina could be mixed with silica and carbon and melted near 2000 C, which would form an aluminium-silicon alloy, as well as CO<sub>2</sub>. This could be separated by cooling the Al-Si mixture to 700 - 1000 ºC and allowing the silicon to solidify and settle out of the melt.<ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
An alternate process involves alumina and carbon processed at high temperatures and low pressure into Al<sub>4</sub>C<sub>3</sub> and carbon monoxide.<ref> [http://en.wikipedia.org/wiki/Aluminium ''Aluminum'' section ''Production and refinement''] </ref><br />
<ref> [http://www.moonminer.com/Lunar_Aluminum.html ''Lunar Aluminum'' at ''Moondust index''] </ref> This breaks down into Aluminum and Carbon between 1900 and 2000 ºC.<ref> [http://en.wikipedia.org/wiki/Aluminum_carbide ''Aluminium carbide'' at ''Wikipedia''] </ref>.<br />
<br />
In either case, CO<sub>2</sub>/CO would have to be recovered and and the [[Lunar Carbon Production|carbon recycled]].<br />
<br />
== See Also ==<br />
<br />
*[[Aluminium]]<br />
*[[Magma Electrolysis]]<br />
*[[ISRU]]<br />
*[[List of Proposed Metal Production Methods]]<br />
<br />
== References ==<br />
<references/><br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Alumina&diff=16581Alumina2011-09-09T18:22:38Z<p>Silverwurm: Page Creation</p>
<hr />
<div>Alumina (also known as [[aluminum]] oxide), has the chemical formula [[Aluminum|Al]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>. Its production is an intermediate step in terrestrial [[aluminum]] production, as well as for several processes proposed for [[lunar aluminum production]].</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Aluminum_Production&diff=16579Lunar Aluminum Production2011-09-09T18:18:54Z<p>Silverwurm: /* Alumina Production */</p>
<hr />
<div>Since Luna lacks any known deposits of bauxite, the ore most commonly used on earth for aluminum production, [[anorthite]] (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>) is most commonly proposed as a lunar substitute.<ref>http://www.permanent.com/l-minera.htm#aluminum</ref> [[Anorthite]] could be separated from the lunar highland material [[Anorthosite]] with mechanical methods. It could then be reduced through various chemical and electrochemical methods to produce [[aluminum]].<br />
<br />
<br />
== Anorthite Production ==<br />
<br />
The [[Anorthosite]] which makes up the Lunar highlands is a mix of [[Plagioclase]]s, [[Olivine]]s, and [[Pyroxene]]s. To separate the [[anorthite]], [[anorthosite]] must be ground. Then, magnetic separation could leave the non-magnetic anorthite.<br />
<br />
The magnetic materials ([[Ilmenite]] and iron oxide) could be stored for production of [[titanium]], [[iron]], and [[oxygen]].<br />
<br />
== Anorthite Refinement ==<br />
<br />
===Direct Reduction===<br />
Main Article: [[FFC Cambridge Process#Aluminum/Silicon/Calcium Production from Anorthite|FFC Cambridge Process]]<br />
<br />
[[Anorthite]] could be directly reduced to its component metals using the [[FFC Cambridge Process]]. The [[Anorthite]] is pressed/sintered into a cathode, which is placed in a bath of molten calcium chloride and electrolyzed. The oxygen is stripped out, leaving behind [[Aluminum]], [[Calcium]], and [[Silicon]].<br />
<br />
This process has the advantage of inherent simplicity, as well as having only one component to recycle, the calcium chloride, which does not react chemically with the inputs, making recovery much simpler. In addition, this process runs at lower temperatures (900º-1100º C) than many other electrolysis procedures, and inert(non-consumable) anodes have been successfully demonstrated with it<ref>http://www.lpi.usra.edu/meetings/roundtable2006/pdf/tripuraneni.pdf</ref>. On the downside, energy must be expended to split all the components of the [[Anorthite]], not just the [[aluminum]]. Splitting the silicon and calcium adds a significant amount of extra energy to the process, as both of them are strong reducers. However, if the silicon and calcium byproducts were needed for other purposes (calcium is a good [[Electrical Conductors|electrical conductor]], and silicon could be used for solar panels or [[In-Situ Propellant Production|rocket fuel]]), this extra energy cost may not be an issue.<br />
<br />
=== Alumina Production ===<br />
<br />
Many processes used on earth or proposed for Lunar use require [[alumina]] ([[Aluminum|Al]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) as an input. On Earth, alumina is produced from bauxite through the Bayer process. As this process is not feasible using Anorthite, another method must be utilized.<br />
<br />
====Vacuum Distillation====<br />
<br />
[[Alumina]] could be produced from Anorthite by boiling out the impurities between 1500 ºC - 2000 ºC under vacuum conditions. The resulting material would be calcium aluminate ([[Ca]][[Al]][[O]]<sub>4</sub>). Raising the temperature further could cause [[alumina]] to volatilize as well. <ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Sulfuric Acid Leaching====<br />
<br />
Another method is to produce calcium aluminate as outlined previously, which is then leached in sulfuric acid, resulting in the following reaction:<br />
<br />
[[Ca]][[Al]]<sub>2</sub>[[O]]<sub>4</sub> + [[Sulfuric Acid |4H<sub>2</sub>SO<sub>4</sub>]] ==> [[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub> + 4[[water |H<sub>2</sub>O]]<br />
<br />
Aluminium sulfate in hexadecahydrate form ([[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) is then separated from calcium sulphate ([[Ca]][[S]][[O]]<sub>4</sub> + [[Al]]<sub>2</sub>([[S]][[O]]<sub>4</sub>)<sub>3</sub>) by filtering and from water by evaporation (and then recovered).<br />
<br />
Finally Alumina is obtained by roasting the aluminum sulfate releasing [[S]]<sub>2</sub>.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref><br />
<br />
====Hydrochloric Acid Leaching====<br />
Another option is to react [[Anorthite]] with hydrochloric acid, which results in following reaction:<br />
<br />
: [[Ca]][[Al]]<sub>2</sub>[[Si]]<sub>2</sub>[[O]]<sub>8</sub> + 8 [[H]][[Cl]] + 2 [[H]]<sub>2</sub>[[O]]==> [[Ca]][[Cl]]<sub>2</sub> + 2 [[Al]][[Cl]]<sub>3</sub>.6 [[H]]<sub>2</sub>[[O]] + 2 [[Si]][[O]]<sub>2</sub><br />
<br />
The calcium chloride and hydrated aluminum chloride dissolve in the solution and are removed. They are then precipitated out of solution, dried, and heated under partial vacuum until the calcium chloride evaporates out of the mix. Temperatures of this range will cause the hydrated aluminum chloride to become [[alumina]], releasing water and hydrogen chloride in the process:<br />
<br />
: 2 AlCl<sub>3</sub>.6 H<sub>2</sub>O ==> Al<sub>2</sub>O<sub>3</sub> + 6 HCl + 3 H<sub>2</sub>O<br />
<br />
The water and hydrogen chloride are separated from the calcium chloride and fed back into the system. The calcium chloride is then electrolyzed into metallic calcium and chlorine. A portion of the recovered water is then [[Water Splitting|split]] into hydrogen and oxygen. The hydrogen component is reacted with the evolved chlorine to produce hydrogen chloride, which is then fed back into the main system.<br />
<br />
=== Direct Calcium Aluminate / Alumina Reduction ===<br />
<br />
Calcium Aluminate (see above for production) could be simply melted and electrolyzed directly, producing aluminum and calcium oxide.<ref>http://www.moonminer.com/Lunar_Aluminum.html</ref> This has two advantages. First, it requires no imported reagents, and second, only the aluminum is split, reducing the amount of energy needed. The disadvantage is that temperatures of approximately 1600 ºC are required, making electrode material of prime concern. Carbon electrodes could be utilized at those temperatures, but the anode would continually wear away as oxygen was produced around it, creating carbon monoxide. The carbon would need to be [[Lunar Carbon Production|recovered]] and new anodes made from it. This effectively means that a rare reagent is needed, negating the process's first stated advantage. Finding an anode material that would produce oxygen without wearing away at those temperatures could be quite difficult.<br />
<br />
Alumina could also be directly melted and electrolyzed in the same fashion. However, this would require temperatures of approximately 2000 ºC, bringing with it again the issue of electrode material.<br />
<br />
=== Hall-Heroult Process ===<br />
<br />
In the Hall-Heroult process, alumina is dissolved in molten cryolite ([[Sodium]] hexafluoroaluminate, Na<sub>3</sub> AlF<sub>6 </sub>) around 1400 ºC. This mix is electrolyzed to separate two byproducts: aluminium and CO<sub>2</sub>. The carbon comes from the consumption of the carbon anode.<br />
<br />
This procedure is used extensively on earth for aluminum production, and as such has the advantage of being a very mature technology. The biggest issue is the consumption of the anode, which would require the produced carbon monoxide to be captured, [[Lunar Carbon Production|converted back into carbon]], and recast into new anodes; an energy intensive process. It is not known if an inert(non-consumable) anode material can be found that would work under these conditions.<ref>http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process</ref><br />
<br />
=== Subchloride Process ===<br />
<br />
In the subchloride process [[alumina]] is reacted with [[carbon]] and [[chlorine]] to yield [[Al]][[Cl]]<sub>3</sub> and [[Carbon dioxide |CO<sub>2</sub>]]. The [[Al]][[Cl]]<sub>3</sub> is electrolyzed to produce [[aluminum]] while recovering the [[chlorine]]. This has the advantage that conventional [[carbon]] electrodes can be used continuously, as the produced [[chlorine]] does not react with them. However, the [[Carbon dioxide |CO<sub>2</sub>]] byproduct must be [[Lunar Carbon Production|recycled]], adding extra complexity and energy requirements to the system. This makes it similar to the Hall-Heroult process in difficulty, except for two advantages. First, the recycled carbon can be directly used in powdered form, it does not need to be recast into electrodes. Second, due to the low melting point of [[Al]][[Cl]]<sub>3</sub> (120 ºC), the process does not require significant energy to melt, and is more easily handled. <ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
=== Carbothermal Reduction ===<br />
<br />
Carbon reduction of Alumina is impossible under normal smelting conditions, due to [[aluminum]]s high reduction potential. However, Alumina could be mixed with silica and carbon and melted near 2000 C, which would form an aluminium-silicon alloy, as well as CO<sub>2</sub>. This could be separated by cooling the Al-Si mixture to 700 - 1000 ºC and allowing the silicon to solidify and settle out of the melt.<ref>http://www.moonminer.com/Lunar_Aluminum.html </ref><br />
<br />
An alternate process involves alumina and carbon processed at high temperatures and low pressure into Al<sub>4</sub>C<sub>3</sub> and carbon monoxide.<ref> [http://en.wikipedia.org/wiki/Aluminium ''Aluminum'' section ''Production and refinement''] </ref><br />
<ref> [http://www.moonminer.com/Lunar_Aluminum.html ''Lunar Aluminum'' at ''Moondust index''] </ref> This breaks down into Aluminum and Carbon between 1900 and 2000 ºC.<ref> [http://en.wikipedia.org/wiki/Aluminum_carbide ''Aluminium carbide'' at ''Wikipedia''] </ref>.<br />
<br />
In either case, CO<sub>2</sub>/CO would have to be recovered and and the [[Lunar Carbon Production|carbon recycled]].<br />
<br />
== See Also ==<br />
<br />
*[[Aluminium]]<br />
*[[Magma Electrolysis]]<br />
*[[ISRU]]<br />
*[[List of Proposed Metal Production Methods]]<br />
<br />
== References ==<br />
<references/><br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Calcium&diff=16555Calcium2011-09-02T19:17:40Z<p>Silverwurm: removed stub note</p>
<hr />
<div>{{Element |<br />
name=Calcium |<br />
symbol=Ca |<br />
available=abundant |<br />
need=essential |<br />
number=20 |<br />
mass=40.078 |<br />
group=2 |<br />
period=4 |<br />
phase=Solid |<br />
series=Alkaline earth metals |<br />
density=1.55 g/cm3 |<br />
melts=1115K,<BR/>842°C,<BR/>1548°F |<br />
boils=1757K,<BR/>1484°C,<BR/>2703°F |<br />
isotopes=40<BR/><BR/>42<BR/>43<BR/>44<BR/>46<BR/>48 |<br />
prior=[[Potassium|<FONT color="#7F7FFF">K</FONT>]] |<br />
next=[[Scandium|<FONT color="#7F7FFF">Sc</FONT>]] |<br />
above=[[Magnesium|<FONT color="#7F7FFF">Mg</FONT>]] |<br />
aprior=[[Sodium|<FONT color="#7F7FFF">Na</FONT>]] |<br />
anext=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
below=[[Strontium|<FONT color="#7F7FFF">Sr</FONT>]] |<br />
bprior=[[Rubidium|<FONT color="#7F7FFF">Rb</FONT>]] |<br />
bnext=[[Yttrium|<FONT color="#7F7FFF">Y</FONT>]] |<br />
radius=180 |<br />
bohr=194 |<br />
covalent=174 |<br />
vdwr= |<br />
irad=(+2) 100 |<br />
ipot=6.11 |<br />
econfig=1s<sup>2</sup> <br/>2s<sup>2</sup> 2p<sup>6</sup> <br/>3s<sup>2</sup> 3p<sup>6</sup> <br/>4s<sup>2</sup> |<br />
eshell=2, 8, 8, 2 |<br />
enega=1 |<br />
eaffin=0.04 |<br />
oxstat=2 |<br />
magn=Paramagnetic |<br />
cryst=Face centered cubic |<br />
}}<br />
'''Calcium''' is a Alkaline earth metal in group 2.<br />
It has a Face centered cubic crystalline structure.<br />
This element has 7 stable isotopes: 40, , 42, 43, 44, 46, and 48. <br />
Its resistivity is 3.91 E-6 ohm cm <ref> [http://www.americanelements.com/ca.html American Elements: Calcium Supplier & Technical Information] </ref><br />
<br />
<br />
== Lunar Production and Use ==<br />
Calcium makes up a significant percentage of the lunar crust, and is expected to be a major byproduct of [[Lunar Aluminium Production|lunar aluminum production]]. By mass, calcium is a better [[electrical conductor]] than both copper and aluminum, and could find uses in electrical wiring. However, as it is highly reactive with oxygen, any use in this manner would be limited to the lunar vacuum or areas containing an inert atmosphere. <br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
== Reference == <br />
<references/> <br />
<BR/><BR/><br />
<br />
[[Category:Paramagnetic Elements]]<br />
[[Category:Solids]]<br />
[[Category:Alkaline Earth Metals]]<br />
[[Category:Critical and Essential Elements]]<br />
<br />
<!-- Generated by a gamma candidate version of Autostub2 (Test 9) --></div>Silverwurmhttps://lunarpedia.org/index.php?title=FFC_Cambridge_Process&diff=16554FFC Cambridge Process2011-09-02T19:15:40Z<p>Silverwurm: /* Aluminum/Silicon/Calcium Production from Anorthite */</p>
<hr />
<div>__TOC__<br />
<br />
<br />
== Introduction ==<br />
<br />
The FFC Cambridge Process reduces oxides to their metal components by electrolysis in a bath of molten [[calcium]] chloride. The process has potential to directly produce [[oxygen]] and metal from virtually any oxide. The process works by placing the oxide to be refined into a bath of molten calcium chloride and creating a voltage differential between the oxide component (which forms the cathode) and an anode which is also placed in the bath. Oxygen is stripped off the cathode, where it forms calcium oxide, which is soluble in the calcium chloride bath. This oxide is split at the anode, producing oxygen. The cathode meanwhile is gradually reduced to a porous metallic sponge.<br />
<br />
The process is currently being developed by Metalysis<ref>http://www.metalysis.com/</ref> for terrestrial metal production, specifically for the production of titanium; the developers hope it will eventually replace the Kroll Process.<br />
<br />
==Application To Lunar Colonization==<br />
In a lunar environment, this process could enable much simpler resource extraction. Experiments have already been done using pellets of [[sintering|sintered]] lunar regolith stimulant, as well as a non-consumable anode, producing metalized pellets and oxygen<ref>http://www.lpi.usra.edu/meetings/roundtable2006/pdf/tripuraneni.pdf</ref>.<br />
<br />
<br />
===Aluminum/Silicon/Calcium Production from Anorthite===<br />
[[Anorthite]] ([[Ca]][[Al]]<SUB>2</SUB>[[Si]]<SUB>2</SUB>[[O]]<SUB>8</SUB>), which makes up much of the Lunar Highlands, could be separated from the regolith by grinding, followed by electrostatic/magnetic [[beneficiation]], and then pressed/sintered into an appropriate cathode. As the oxygen is stripped off, metallic [[aluminum]], [[silicon]], and [[calcium]] are produced. The [[calcium]] is soluble in the calcium chloride bath, and would need to be continuously distilled out to keep the calcium concentration from becoming too high (which can reduce current efficiencies). Since silicon is not very soluble in aluminum at bath temperatures (900-1100 C), the aluminum and silicon should separate, the silicon remaining solid, the aluminum melting. This molten aluminum is denser than calcium chloride, and should drip out and collect at the bottom, where it can be siphoned off. Once the [[anorthite]] cathode is completely reduced, a very porous sponge of silicon remains.<br />
<br />
For every metric ton of Anorthite processed in this manner, approximately 460 kg [[oxygen]], 193 kg [[aluminum]], 201 kg [[silicon]], and 144 kg [[calcium]] would be obtained.<br />
<br />
===Iron/Titanium Production from Ilmenite===<br />
[[Ilmenite]] ([[Fe]][[Ti]][[O]]<SUB>3</SUB>), is found in abundance on the lunar Maria and is easily separated through magnetic means. This substance could be processed in the same fashion as [[Anorthite]], resulting in a 54% [[Iron]], 46% [[Titanium]] sponge. Separating this alloy into [[iron]] and [[titanium]] could be done by either distillation or [[Carbonyl process|carbonyl extraction]].<br />
<br />
Another option is to first subject the [[Ilmenite]] to [[Ilmenite_Reduction#Hydrogen_Reduction|Hydrogen Reduction]], producing [[Iron]] and [[rutile|titanium dioxide]]. The iron could then be separated by [[Carbonyl process|carbonyl extraction]], distillation, grinding followed by use of a magnet, or by melting and then allowing the products to separate out. The remaining titanium dioxide could then be run through the FFC Cambridge process, producing a titanium sponge.<br />
<br />
The end result for each ton would be approximately 316 kg [[Oxygen]], 316 kg [[Titanium]], and 368 kg [[Iron]].<br />
<br />
===Other Products===<br />
Lunar [[Chromite]] could also be reduced in the same fashion, producing Ferrochrome, which could be used to add [[Chromium]] content to [[Iron]] alloys. Many of the above listed reductions would also contain amounts of [[Magnesium]] and [[Sodium]] (Lunar [[Ilmenite]] in particular is known to be highly enriched with [[Magnesium]]), which could be distilled out fairly easily due to their low boiling points.<br />
<br />
<br />
===Chlorine Recovery===<br />
The only substance used which is not readily available on the Lunar surface is [[chlorine]]. Chlorine is available on the lunar surface in the form of [[Apatite]] ([[Ca]]<sub>10</sub>([[P]][[O]]<sub>4</sub>)<sub>6</sub>([[O]][[H]], [[F]], [[Cl]], [[Br]])<sub>2</sub>), but only in trace quantities. If a viable procedure for concentrating apatite out of the lunar regolith is not found, then a high degree of chlorine recycling would be necessary for the FFC Cambridge process to be useful in a lunar environment.<br />
<br />
Chlorine losses from the system would come in the form of calcium chloride trapped in the pores of the metallic sponge produced in the reduction process, as well as any amount lost from the distillation of calcium metal out of the bath during anorthite processing. The latter losses could be reduced to acceptable levels through careful design of the distillation equipment.<br />
<br />
In terrestrial applications, the salt trapped in the pores of the sponge is removed by grinding the sponge and washing the resulting powder with water, as calcium chloride is highly water soluble. The same procedure could be followed in a lunar environment, followed by reverse osmosis and distillation to recover the dissolved salt.<br />
<br />
A simpler method is to melt the sponge, which would be required for many processes anyway. Since calcium chloride is not soluble in (and less dense than) most metals, it should separate into a distinct top layer, where it can be easily drained off, while the metallic elements are drained from the bottom.<br />
<br />
Another method involves heating the sponge under partial vacuum until the calcium chloride evaporates out. This is useful in circumstances where the sponge itself is the desired product. Proper design of the process should allow for sufficient salt removal.<br />
<br />
<br />
<br />
== References ==<br />
<references/><br />
<br />
== External Links ==<br />
[http://en.wikipedia.org/wiki/Ffc_cambridge_process FFC Cambridge process on Wikipedia]<br />
<br />
<br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=FFC_Cambridge_Process&diff=16553FFC Cambridge Process2011-09-02T19:13:48Z<p>Silverwurm: /* Iron/Titanium Production from Ilmenite */</p>
<hr />
<div>__TOC__<br />
<br />
<br />
== Introduction ==<br />
<br />
The FFC Cambridge Process reduces oxides to their metal components by electrolysis in a bath of molten [[calcium]] chloride. The process has potential to directly produce [[oxygen]] and metal from virtually any oxide. The process works by placing the oxide to be refined into a bath of molten calcium chloride and creating a voltage differential between the oxide component (which forms the cathode) and an anode which is also placed in the bath. Oxygen is stripped off the cathode, where it forms calcium oxide, which is soluble in the calcium chloride bath. This oxide is split at the anode, producing oxygen. The cathode meanwhile is gradually reduced to a porous metallic sponge.<br />
<br />
The process is currently being developed by Metalysis<ref>http://www.metalysis.com/</ref> for terrestrial metal production, specifically for the production of titanium; the developers hope it will eventually replace the Kroll Process.<br />
<br />
==Application To Lunar Colonization==<br />
In a lunar environment, this process could enable much simpler resource extraction. Experiments have already been done using pellets of [[sintering|sintered]] lunar regolith stimulant, as well as a non-consumable anode, producing metalized pellets and oxygen<ref>http://www.lpi.usra.edu/meetings/roundtable2006/pdf/tripuraneni.pdf</ref>.<br />
<br />
<br />
===Aluminum/Silicon/Calcium Production from Anorthite===<br />
[[Anorthite]] ([[Ca]][[Al]]<SUB>2</SUB>[[Si]]<SUB>2</SUB>[[O]]<SUB>8</SUB>), which makes up much of the Lunar Highlands, could be separated from the regolith by grinding, followed by electrostatic/magnetic [[beneficiation]], and then pressed/sintered into an appropriate cathode. As the oxygen is stripped off, metallic [[aluminum]], [[silicon]], and [[calcium]] are produced. The [[calcium]] is soluble in the calcium chloride bath, and will need to be continuously distilled out to keep the calcium concentration from becoming too high (which can reduce current efficiencies). Since silicon is not very soluble in aluminum at bath temperatures (900-1100 C), the aluminum and silicon should separate, the silicon remaining solid, the aluminum melting. This molten aluminum is denser than calcium chloride, and should drip out and collect at the bottom, where it can be siphoned off. Once the [[anorthite]] cathode is completely reduced, a very porous sponge of silicon remains.<br />
<br />
For every metric ton of Anorthite processed in this manner, approximately 460 kg [[oxygen]], 193 kg [[aluminum]], 201 kg [[silicon]], and 144 kg [[calcium]] would be obtained.<br />
<br />
===Iron/Titanium Production from Ilmenite===<br />
[[Ilmenite]] ([[Fe]][[Ti]][[O]]<SUB>3</SUB>), is found in abundance on the lunar Maria and is easily separated through magnetic means. This substance could be processed in the same fashion as [[Anorthite]], resulting in a 54% [[Iron]], 46% [[Titanium]] sponge. Separating this alloy into [[iron]] and [[titanium]] could be done by either distillation or [[Carbonyl process|carbonyl extraction]].<br />
<br />
Another option is to first subject the [[Ilmenite]] to [[Ilmenite_Reduction#Hydrogen_Reduction|Hydrogen Reduction]], producing [[Iron]] and [[rutile|titanium dioxide]]. The iron could then be separated by [[Carbonyl process|carbonyl extraction]], distillation, grinding followed by use of a magnet, or by melting and then allowing the products to separate out. The remaining titanium dioxide could then be run through the FFC Cambridge process, producing a titanium sponge.<br />
<br />
The end result for each ton would be approximately 316 kg [[Oxygen]], 316 kg [[Titanium]], and 368 kg [[Iron]].<br />
<br />
===Other Products===<br />
Lunar [[Chromite]] could also be reduced in the same fashion, producing Ferrochrome, which could be used to add [[Chromium]] content to [[Iron]] alloys. Many of the above listed reductions would also contain amounts of [[Magnesium]] and [[Sodium]] (Lunar [[Ilmenite]] in particular is known to be highly enriched with [[Magnesium]]), which could be distilled out fairly easily due to their low boiling points.<br />
<br />
<br />
===Chlorine Recovery===<br />
The only substance used which is not readily available on the Lunar surface is [[chlorine]]. Chlorine is available on the lunar surface in the form of [[Apatite]] ([[Ca]]<sub>10</sub>([[P]][[O]]<sub>4</sub>)<sub>6</sub>([[O]][[H]], [[F]], [[Cl]], [[Br]])<sub>2</sub>), but only in trace quantities. If a viable procedure for concentrating apatite out of the lunar regolith is not found, then a high degree of chlorine recycling would be necessary for the FFC Cambridge process to be useful in a lunar environment.<br />
<br />
Chlorine losses from the system would come in the form of calcium chloride trapped in the pores of the metallic sponge produced in the reduction process, as well as any amount lost from the distillation of calcium metal out of the bath during anorthite processing. The latter losses could be reduced to acceptable levels through careful design of the distillation equipment.<br />
<br />
In terrestrial applications, the salt trapped in the pores of the sponge is removed by grinding the sponge and washing the resulting powder with water, as calcium chloride is highly water soluble. The same procedure could be followed in a lunar environment, followed by reverse osmosis and distillation to recover the dissolved salt.<br />
<br />
A simpler method is to melt the sponge, which would be required for many processes anyway. Since calcium chloride is not soluble in (and less dense than) most metals, it should separate into a distinct top layer, where it can be easily drained off, while the metallic elements are drained from the bottom.<br />
<br />
Another method involves heating the sponge under partial vacuum until the calcium chloride evaporates out. This is useful in circumstances where the sponge itself is the desired product. Proper design of the process should allow for sufficient salt removal.<br />
<br />
<br />
<br />
== References ==<br />
<references/><br />
<br />
== External Links ==<br />
[http://en.wikipedia.org/wiki/Ffc_cambridge_process FFC Cambridge process on Wikipedia]<br />
<br />
<br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Titanium_Production&diff=16552Lunar Titanium Production2011-09-02T19:10:01Z<p>Silverwurm: /* Hydrogen Reduction */</p>
<hr />
<div>== Introduction ==<br />
<br />
The main source of Lunar [[Titanium]] is in the form of [[Ilmenite]] ([[Iron|Fe]][[Titanium|Ti]][[Oxygen|O]]<sub>3</sub>). This material is found abundantly on the lunar surface, especially on the Maria. Being weakly magnetic, Ilmenite could be concentrated from the lunar regolith in a magnetic separator (a multistage device may be necessary due to other magnetic minerals present). There are several ways Titanium could be produced in a Lunar environment.<br />
<br />
<br />
== Terrestrial Production ==<br />
<br />
On earth, Ilmenite is subjected to the Chloride Process<ref>http://en.wikipedia.org/wiki/Chloride_process</ref>, where it is reacted with [[carbon]] and [[chlorine]] to produce titanium and iron chlorides according to the formula:<br />
<br />
:2 [[Ilmenite|FeTiO<sub>3</sub>]] + 7 [[Cl]]<sub>2</sub> + 6 [[C]] → 2 [[Ti]][[Cl]]<sub>4</sub> + 2 [[Fe]][[Cl]]<sub>3</sub> + 6 [[Carbon Monoxide | CO]]<br />
<br />
The titanium tetrachloride is separated from the other reaction products by distillation. Once separated, it is reacted with liquid [[magnesium]] in the Kroll process<ref>http://en.wikipedia.org/wiki/Kroll_process</ref>, producing [[titanium]] metal and [[magnesium]] chloride:<br />
<br />
:[[Ti]][[Cl]]<sub>4</sub> + 2[[Mg]] → Ti + 2 [[Mg]][[Cl]]<sub>2</sub><br />
<br />
The resulting sponge of [[titanium]] metal is then either crushed and washed or subjected to vacuum distillation to remove the magnesium chloride, and then melted and further refined to the desired purity.<br />
<br />
<br />
It is possible to adapt this process to a lunar environment, though it presents some challenges. The [[chlorine]] and [[carbon]] required in the process would have to be stringently recycled, as they are rare (and hence likely to be quite expensive) in a lunar environment. The [[magnesium]] and [[iron]] chlorides would need to be electrolyzed to their respective metals, recovering the [[chlorine]]. Recovering the [[carbon]] and [[oxygen]] from the [[carbon monoxide]] is a bit less straightforward, [[Lunar Carbon Production|though several methods exist]].<br />
<br />
== Hydrogen Reduction ==<br />
see also: [[Ilmenite_Reduction#Hydrogen Reduction|Hydrogen Reduction]]<br />
<br />
Ilmenite could be reacted with [[hydrogen]], producing [[iron]] and [[rutile|titanium dioxide]]. The iron could then be separated by [[Carbonyl process|carbonyl extraction]], distillation, grinding and removing the iron particles with a magnet, or melting and then allowing the products to separate. The [[rutile|titanium dioxide]] would then be refined by other means.<br />
<br />
== FFC Cambridge Process ==<br />
Main Article: [[FFC Cambridge Process#Iron/Titanium Production from Ilmenite|FFC Cambridge Process]].<br />
<br />
The FFC Cambridge Process is a method of performing electrolysis on solid metal oxides. The oxide to be reduced is formed into a cathode and subjected to electrolysis in a molten calcium chloride bath. Oxygen is stripped off and bubbles off at the anode, leaving behind a metallic sponge.<br />
<br />
The FFC Cambridge process could be used on the titanium dioxide produced from hydrogen reduction of Ilmenite, or the [[Ilmenite]] could be directly reduced, producing an [[Iron]]-[[Titanium]] alloy, which is then separated by [[Carbonyl process|carbonyl extraction]] or distillation.<br />
<br />
== References ==<br />
<references/><br />
<br />
[[Category:Industrial Production]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Steel&diff=16551Steel2011-09-02T19:03:35Z<p>Silverwurm: Redirected page to Iron</p>
<hr />
<div>#REDIRECT [[Iron]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16550Lunar Settlement Artificial Atmosphere2011-09-02T19:00:26Z<p>Silverwurm: /* Pressure/Gas Combination */</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Pressure/Gas Combination ==<br />
<br />
Exact choice of a habitats internal pressure and gas combination will have various effects on the inhabitants and the structure itself. Pressure is expected to be used to support the lunar structure under normal operation, though the level required for this is low enough that virtually any livable level will be more than enough (see [[Roof Support]]). As such, the higher the habitat pressure, the stronger a habitat must be constructed to withstand it. In addition, a high pressure interior will loose atmosphere faster than a low pressure one if a leak is developed. The choice of gas combination will greatly effect the achievable pressures.<br />
<br />
Since [[Oxygen]] is expected to be a major by-product of [[manufacturing activities]] on the moon, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. To avoid fires, the partial pressure of oxygen in the habitat must be kept to earth like levels (no more than 21 kPa / 3 psi). This low pressure is advantageous, and the lack of any filler gasses would greatly simplify atmospheric processing equipment. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, early designs of the Apollo spacecraft, and is currently used in spacesuits. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> However, as mentioned previously, a pure oxygen environment is useful for space suits, as pressure must be kept low in order for the suit to stay pliable. Using a pure oxygen environment for space suits and a high pressure mixed environment for the habitat would require a period of breathing pure oxygen before donning the suit in order to remove all nitrogen from the blood and avoid decompression sickness (also known the bends). This is currently practiced on the ISS.<br />
<br />
A combination of one or more [[inert gases]] with [[Oxygen]] would allow proper oxygenation over longer time-frames. Examples include [[nitrogen]], [[helium]], and [[argon]], all of which are present in the lunar regolith and can be extracted by heating (see [[volatiles]]. [[Nitrogen]] is attractive as it would allow for an earthlike mix, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. [[Argon]], even less abundant than [[nitrogen]], would also have this problem. [[Helium]] could also be added to the oxygen mix, as it is more abundant in lunar soil, and its low density means significantly less mass is required for a given volume. However, the addition of any appreciable quantities of helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
Another factor to consider with any combination is the direct effects of pressure. The most notable effect is in the boiling point of water, which would decrease with decreasing pressure.<br />
<br />
{| border=1<br />
! colspan="2" | Total Pressure !! colspan = "2" | Boiling Point Of Water !! Comments<br />
|-<br />
| kPa || psi || °C || °F || <br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || Sea Level, ISS<br />
|-<br />
| 84 || 12.17 || 95 || 203 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || Top of Mount Everest<br />
|}<br />
<br />
The main problem this would pose would be cooking of food, as lower boiling points would make many foods impractical to cook. However, these foods could still be prepared using a pressure cooker. Many hikers utilize lightweight pressure cookers for this purpose when climbing to high altitudes, and adapting such devices to lunar use should not be difficult.<br />
<br />
== Agriculture ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref>, like humans, are capable of tolerating lower atmospheric pressure so long as all required gasses are available. Some studies indicate that plants can survive at pressures lower than any human can. Whatever the pressure, an environment optimized for plant growth would benefit from having an atmosphere enriched with carbon dioxide, as they would grow faster. This enrichment is used in some terrestrial greenhouses for both growth boosting and pest control, as plants will tolerate co2 levels that will kill insects.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16549Lunar Settlement Artificial Atmosphere2011-09-02T18:54:04Z<p>Silverwurm: /* Pressure/Gas Combination */ added discussion of low pressure spacesuits requireing prebreathing, moved from roof support</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Pressure/Gas Combination ==<br />
<sub>(See also: [[Atmosphere]])</sub><br />
<br />
Exact choice of a habitats internal pressure and gas combination will have various effects on the inhabitants and the structure itself. Pressure is expected to be used to support the lunar structure under normal operation, though the level required for this is low enough that virtually any livable level will be more than enough (see [[Roof Support]]). As such, the higher the habitat pressure, the stronger a habitat must be constructed to withstand it. In addition, a high pressure interior will loose atmosphere faster than a low pressure one if a leak is developed. The choice of gas combination will greatly effect the achievable pressures.<br />
<br />
Since [[Oxygen]] is expected to be a major by-product of [[manufacturing activities]] on the moon, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. To avoid fires, the partial pressure of oxygen in the habitat must be kept to earth like levels (no more than 21 kPa / 3 psi). This low pressure is advantageous, and the lack of any filler gasses would greatly simplify atmospheric processing equipment. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, early designs of the Apollo spacecraft, and is currently used in spacesuits. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> However, as mentioned previously, a pure oxygen environment is useful for space suits, as pressure must be kept low in order for the suit to stay pliable. Using a pure oxygen environment for space suits and a high pressure mixed environment for the habitat would require a period of breathing pure oxygen before donning the suit in order to remove all nitrogen from the blood and avoid decompression sickness (also known the bends). This is currently practiced on the ISS.<br />
<br />
A combination of one or more [[inert gases]] with [[Oxygen]] would allow proper oxygenation over longer time-frames. Examples include [[nitrogen]], [[helium]], and [[argon]], all of which are present in the lunar regolith and can be extracted by heating (see [[volatiles]]. [[Nitrogen]] is attractive as it would allow for an earthlike mix, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. [[Argon]], even less abundant than [[nitrogen]], would also have this problem. [[Helium]] could also be added to the oxygen mix, as it is more abundant in lunar soil, and its low density means significantly less mass is required for a given volume. However, the addition of any appreciable quantities of helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
Another factor to consider with any combination is the direct effects of pressure. The most notable effect is in the boiling point of water, which would decrease with decreasing pressure.<br />
<br />
{| border=1<br />
! colspan="2" | Total Pressure !! colspan = "2" | Boiling Point Of Water !! Comments<br />
|-<br />
| kPa || psi || °C || °F || <br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || Sea Level, ISS<br />
|-<br />
| 84 || 12.17 || 95 || 203 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || Top of Mount Everest<br />
|}<br />
<br />
The main problem this would pose would be cooking of food, as lower boiling points would make many foods impractical to cook. However, these foods could still be prepared using a pressure cooker. Many hikers utilize lightweight pressure cookers for this purpose when climbing to high altitudes, and adapting such devices to lunar use should not be difficult.<br />
<br />
== Agriculture ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref>, like humans, are capable of tolerating lower atmospheric pressure so long as all required gasses are available. Some studies indicate that plants can survive at pressures lower than any human can. Whatever the pressure, an environment optimized for plant growth would benefit from having an atmosphere enriched with carbon dioxide, as they would grow faster. This enrichment is used in some terrestrial greenhouses for both growth boosting and pest control, as plants will tolerate co2 levels that will kill insects.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16548Roof Support2011-09-02T18:46:47Z<p>Silverwurm: pressure discussion removed, belongs on atmophere page</p>
<hr />
<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitant, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]). Most of the thickness called for in this blanket is to protect against cosmic radiation.<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver, a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitational acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. Even if a structure was only pressurized to equal the peak of mount everest, it would be able to support sea level radiation shielding and still have a net outward force. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around one sixth of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure balance would be quite different.<br />
<br />
As a result, a lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces of pressure are greater. A lunar habitat could therefore be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining standard atmospheric pressure six feet underwater in an emergency, as well as containing twice atmospheric pressure under the same conditions normally. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, designing it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. Multiple air bladders around the outsize, also compartmentalized, would also aid in reducing the chance of a blowout. An additional safety measure that could be installed is for each section of the habitat to have its own backup gas tank, which would open in case of a pressure loss, feeding the leak until an patch job / evacuation could be achieved. Since the minimum pressure that needs to be maintained is quite low (as discussed previously), this approach could be utilized with a modestly sized backup tank.<br />
<br />
<br />
<br />
{{Hazards}}<br />
<br />
<br />
[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16547Lunar Settlement Artificial Atmosphere2011-09-02T18:45:14Z<p>Silverwurm: Reformatted, moved chart from roof support here</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Pressure/Gas Combination ==<br />
<sub>(See also: [[Atmosphere]])</sub><br />
<br />
Exact choice of a habitats internal pressure and gas combination will have various effects on the inhabitants and the structure itself. Pressure is expected to be used to support the lunar structure under normal operation, though the level required for this is low enough that virtually any livable level will be more than enough (see [[Roof Support]]). As such, the higher the habitat pressure, the stronger a habitat must be constructed to withstand it. In addition, a high pressure interior will loose atmosphere faster than a low pressure one if a leak is developed. The choice of gas combination will greatly effect the achievable pressures.<br />
<br />
Since [[Oxygen]] is expected to be a major by-product of [[manufacturing activities]] on the moon, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. To avoid fires, the partial pressure of oxygen in the habitat must be kept to earth like levels (no more than 21 kPa / 3 psi). This low pressure is advantageous, and the lack of any filler gasses would greatly simplify atmospheric processing equipment. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, early designs of the Apollo spacecraft, and is currently used in spacesuits. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref><br />
<br />
A combination of one or more [[inert gases]] with [[Oxygen]] would allow proper oxygenation over longer time-frames. Examples include [[nitrogen]], [[helium]], and [[argon]], all of which are present in the lunar regolith and can be extracted by heating (see [[volatiles]]. [[Nitrogen]] is attractive as it would allow for an earthlike mix, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. [[Argon]], even less abundant than [[nitrogen]], would also have this problem. [[Helium]] could also be added to the oxygen mix, as it is more abundant in lunar soil, and its low density means significantly less mass is required for a given volume. However, the addition of any appreciable quantities of helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
Another factor to consider with any combination is the direct effects of pressure. The most notable effect is in the boiling point of water, which would decrease with decreasing pressure.<br />
<br />
{| border=1<br />
! colspan="2" | Total Pressure !! colspan = "2" | Boiling Point Of Water !! Comments<br />
|-<br />
| kPa || psi || °C || °F || <br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || Sea Level, ISS<br />
|-<br />
| 84 || 12.17 || 95 || 203 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || Top of Mount Everest<br />
|}<br />
<br />
The main problem this would pose would be cooking of food, the lower boiling point would make many foods impractical to cook. However, these foods could still be prepared using a pressure cooker.<br />
<br />
<br />
<br />
== Agriculture ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref>, like humans, are capable of tolerating lower atmospheric pressure so long as all required gasses are available. Some studies indicate that plants can survive at pressures lower than any human can. Whatever the pressure, an environment optimized for plant growth would benefit from having an atmosphere enriched with carbon dioxide, as they would grow faster. This enrichment is used in some terrestrial greenhouses for both growth boosting and pest control, as plants will tolerate co2 levels that will kill insects.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16546Roof Support2011-09-02T17:51:13Z<p>Silverwurm: /* Safety considerations */</p>
<hr />
<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitant, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]). Most of the thickness called for in this blanket is to protect against cosmic radiation.<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver, a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitational acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. Even if a structure was only pressurized to equal the peak of mount everest, it would be able to support sea level radiation shielding and still have a net outward force. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around one sixth of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure balance would be quite different.<br />
<br />
As a result, a lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces of pressure are greater. A lunar habitat could therefore be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining standard atmospheric pressure six feet underwater in an emergency, as well as containing twice atmospheric pressure under the same conditions normally. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, designing it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. Multiple air bladders around the outsize, also compartmentalized, would also aid in reducing the chance of a blowout. An additional safety measure that could be installed is for each section of the habitat to have its own backup gas tank, which would open in case of a pressure loss, feeding the leak until an patch job / evacuation could be achieved. Since the minimum pressure that needs to be maintained is quite low (as discussed previously), this approach could be utilized with a modestly sized backup tank.<br />
<br />
==Pressure Considerations==<br />
<br />
<br />
One of the most important considerations in the design of a lunar settlement will be the internal air pressure.<br />
<br />
===High Pressure===<br />
<br />
High air pressure, that is Earth normal 101 kpa (14.2 PSI, makes the living space more Earth like. People and plants accommodate to living on the Moon easily and food is easy to cook.<br />
<br />
But, spacesuits must be at low pressure for the joints to work with acceptable amounts of efforts. Any time a persons moves from a high pressure to a low pressure environment, you risk nitrogen forming bubbles in your blood; a conditions called the bends. For the body to accommodate from normal air pressure to a low spacesuit pressure can take as long as an overnight stay in a low pressure chamber.<br />
<br />
===Low Pressure===<br />
<br />
Low air pressure, with adequate oxygen content, allows the human body to accommodation to spacesuit pressures in only a few minutes or just seconds in an emergency. Ranges from 74 kPa (10.2 psi) down to 33.5 kpi (4.7 psi) have been discussed for lunar settlements. The human body will simply never fully accommodate pressures below about 30 kPascal (4.2 psi). <br />
<br />
At low pressures you can use 100% oxygen which greatly simplifies the entire life support system. Testing this type of system is very dangerous and has resulted in two serious fires. The key safety concept is that if the partial pressure of oxygen exceeds Earth normal of 22 kPascal (3.0 psi) then substancial fire control efforts are required.<br />
<br />
The long term health effects of low pressure are not fully known for people or for plants. Any agricultural areas may need additional CO2, humidity, and nitrogen compared the people living areas. <br />
<br />
Low pressure also saves the cost of shipping a large mass of bulk nitrogen from Earth. This could be a very important cost consideration in early lunar settlements.<br />
<br />
Water boils at such a low temperature at low atmospheric pressure that cooking is difficult. You simply cannot get things hot enough to really taste right. A cup of tea that you can stir with your finger is simply not worth drinking.<br />
<br />
Also low air pressure will not support as thick a layer of protecting regolith over inflated buildings.<br />
<br />
===Supporting Regolith===<br />
<br />
Here are some of present ideas for lunar settlement air pressures and how much regolith they will support:<br />
<br />
<br />
{| border=1<br />
! colspan="2" | Pressure !! colspan="2" | Boiling Point Of Water !! Regolith Needed to Equal Atmospheric Shielding !! Maximum Regolith Supported !!Comment<br />
|-<br />
| kPa || psi || °C || °F || m || m ||<br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || 5.4 || 32 || Sea Level, ISS body<br />
|-<br />
| 84 || 12.17 || 95 || 203 || 4.5 || 27 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || 4.3 || 26 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || 4.0 || 24 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || 3.2 || 19 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || 1.8 || 10 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || 1.6 || 9.9 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || 1.4 || 8.4 || Top of Mount Everest<br />
|-<br />
| 10.0 || 1.5 || 46 || 115 || 0.5 || 3.2 || 1/10 Atm, 16,000 m, unconscious in 10 sec<br />
|}<br />
<br />
The Regolith Shield column shows how much lunar regolith is needed to provide radiation shielding equivalent to the air above your head at these locations on Earth. The Regolith Support column shows how much lunar regolith can be supported on the Moon by that level of internal pressure.<br />
<br />
These calculations are based on the following parameters:<br />
<br />
{| border=1<br />
| density of packed regolith || 1.9 || g/cm^3 || Used for this calculation<br />
|-<br />
| density of loose regolith || 1.5 || g/cm^3 || just poured in a pile<br />
|-<br />
| Lunar gravity || 1.63 || m/s^2 || about 1/6 Earth<br />
|-<br />
| Human body temperature || 37.0 || C || 98.6 F<br />
<br />
|}<br />
<br />
<br />
It is important to note that the internal pressure inside a living area has plenty of force to support a substantial thickness of lunar regolith above it for radiation and thermal shielding even if low pressures are used.<br />
<br />
<br />
<br />
{{Hazards}}<br />
<br />
<br />
[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16545Roof Support2011-09-02T17:46:58Z<p>Silverwurm: /* Safety considerations */</p>
<hr />
<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitant, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]). Most of the thickness called for in this blanket is to protect against cosmic radiation.<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitational acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. Even if a structure was only pressurized to equal the peak of mount everest, it would be able to support sea level radiation shielding and still have a net outward force. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around one sixth of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure balance would be quite different.<br />
<br />
As a result, a lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces of pressure are greater. A lunar habitat could therefore be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining standard atmospheric pressure six feet underwater in an emergency, as well as containing twice atmospheric pressure under the same conditions normally. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, designing it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. Multiple air bladders around the outsize, also compartmentalized, would also aid in reducing the chance of a blowout. An additional safety measure that could be installed is for each section of the habitat to have its own backup gas tank, which would open in case of a pressure loss, feeding the leak until an patch job / evacuation could be achieved. Since the minimum pressure that needs to be maintained is quite low (as discussed previously), this approach could be utilized with a modestly sized backup tank.<br />
<br />
==Pressure Considerations==<br />
<br />
<br />
One of the most important considerations in the design of a lunar settlement will be the internal air pressure.<br />
<br />
===High Pressure===<br />
<br />
High air pressure, that is Earth normal 101 kpa (14.2 PSI, makes the living space more Earth like. People and plants accommodate to living on the Moon easily and food is easy to cook.<br />
<br />
But, spacesuits must be at low pressure for the joints to work with acceptable amounts of efforts. Any time a persons moves from a high pressure to a low pressure environment, you risk nitrogen forming bubbles in your blood; a conditions called the bends. For the body to accommodate from normal air pressure to a low spacesuit pressure can take as long as an overnight stay in a low pressure chamber.<br />
<br />
===Low Pressure===<br />
<br />
Low air pressure, with adequate oxygen content, allows the human body to accommodation to spacesuit pressures in only a few minutes or just seconds in an emergency. Ranges from 74 kPa (10.2 psi) down to 33.5 kpi (4.7 psi) have been discussed for lunar settlements. The human body will simply never fully accommodate pressures below about 30 kPascal (4.2 psi). <br />
<br />
At low pressures you can use 100% oxygen which greatly simplifies the entire life support system. Testing this type of system is very dangerous and has resulted in two serious fires. The key safety concept is that if the partial pressure of oxygen exceeds Earth normal of 22 kPascal (3.0 psi) then substancial fire control efforts are required.<br />
<br />
The long term health effects of low pressure are not fully known for people or for plants. Any agricultural areas may need additional CO2, humidity, and nitrogen compared the people living areas. <br />
<br />
Low pressure also saves the cost of shipping a large mass of bulk nitrogen from Earth. This could be a very important cost consideration in early lunar settlements.<br />
<br />
Water boils at such a low temperature at low atmospheric pressure that cooking is difficult. You simply cannot get things hot enough to really taste right. A cup of tea that you can stir with your finger is simply not worth drinking.<br />
<br />
Also low air pressure will not support as thick a layer of protecting regolith over inflated buildings.<br />
<br />
===Supporting Regolith===<br />
<br />
Here are some of present ideas for lunar settlement air pressures and how much regolith they will support:<br />
<br />
<br />
{| border=1<br />
! colspan="2" | Pressure !! colspan="2" | Boiling Point Of Water !! Regolith Needed to Equal Atmospheric Shielding !! Maximum Regolith Supported !!Comment<br />
|-<br />
| kPa || psi || °C || °F || m || m ||<br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || 5.4 || 32 || Sea Level, ISS body<br />
|-<br />
| 84 || 12.17 || 95 || 203 || 4.5 || 27 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || 4.3 || 26 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || 4.0 || 24 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || 3.2 || 19 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || 1.8 || 10 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || 1.6 || 9.9 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || 1.4 || 8.4 || Top of Mount Everest<br />
|-<br />
| 10.0 || 1.5 || 46 || 115 || 0.5 || 3.2 || 1/10 Atm, 16,000 m, unconscious in 10 sec<br />
|}<br />
<br />
The Regolith Shield column shows how much lunar regolith is needed to provide radiation shielding equivalent to the air above your head at these locations on Earth. The Regolith Support column shows how much lunar regolith can be supported on the Moon by that level of internal pressure.<br />
<br />
These calculations are based on the following parameters:<br />
<br />
{| border=1<br />
| density of packed regolith || 1.9 || g/cm^3 || Used for this calculation<br />
|-<br />
| density of loose regolith || 1.5 || g/cm^3 || just poured in a pile<br />
|-<br />
| Lunar gravity || 1.63 || m/s^2 || about 1/6 Earth<br />
|-<br />
| Human body temperature || 37.0 || C || 98.6 F<br />
<br />
|}<br />
<br />
<br />
It is important to note that the internal pressure inside a living area has plenty of force to support a substantial thickness of lunar regolith above it for radiation and thermal shielding even if low pressures are used.<br />
<br />
<br />
<br />
{{Hazards}}<br />
<br />
<br />
[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16544Roof Support2011-09-02T17:44:58Z<p>Silverwurm: /* Safety considerations */</p>
<hr />
<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitant, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]). Most of the thickness called for in this blanket is to protect against cosmic radiation.<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitational acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. Even if a structure was only pressurized to equal the peak of mount everest, it would be able to support sea level radiation shielding and still have a net outward force. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around one sixth of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure balance would be quite different.<br />
<br />
As a result, a lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces of pressure are greater. A lunar habitat could therefor be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining standard atmospheric pressure six feet underwater in an emergency, as well as containing twice atmospheric pressure under the same conditions normally. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, designing it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. Multiple air bladders around the outsize, also compartmentalized, would also aid in reducing the chance of a blowout. An additional safety measure that could be installed is for each section of the habitat to have its own backup gas tank, which would open in case of a pressure loss, feeding the leak until an patch job / evacuation could be achieved. Since the minimum pressure that needs to be maintained is quite low (as discussed previously), this approach could be utilized with a modestly sized backup tank.<br />
<br />
==Pressure Considerations==<br />
<br />
<br />
One of the most important considerations in the design of a lunar settlement will be the internal air pressure.<br />
<br />
===High Pressure===<br />
<br />
High air pressure, that is Earth normal 101 kpa (14.2 PSI, makes the living space more Earth like. People and plants accommodate to living on the Moon easily and food is easy to cook.<br />
<br />
But, spacesuits must be at low pressure for the joints to work with acceptable amounts of efforts. Any time a persons moves from a high pressure to a low pressure environment, you risk nitrogen forming bubbles in your blood; a conditions called the bends. For the body to accommodate from normal air pressure to a low spacesuit pressure can take as long as an overnight stay in a low pressure chamber.<br />
<br />
===Low Pressure===<br />
<br />
Low air pressure, with adequate oxygen content, allows the human body to accommodation to spacesuit pressures in only a few minutes or just seconds in an emergency. Ranges from 74 kPa (10.2 psi) down to 33.5 kpi (4.7 psi) have been discussed for lunar settlements. The human body will simply never fully accommodate pressures below about 30 kPascal (4.2 psi). <br />
<br />
At low pressures you can use 100% oxygen which greatly simplifies the entire life support system. Testing this type of system is very dangerous and has resulted in two serious fires. The key safety concept is that if the partial pressure of oxygen exceeds Earth normal of 22 kPascal (3.0 psi) then substancial fire control efforts are required.<br />
<br />
The long term health effects of low pressure are not fully known for people or for plants. Any agricultural areas may need additional CO2, humidity, and nitrogen compared the people living areas. <br />
<br />
Low pressure also saves the cost of shipping a large mass of bulk nitrogen from Earth. This could be a very important cost consideration in early lunar settlements.<br />
<br />
Water boils at such a low temperature at low atmospheric pressure that cooking is difficult. You simply cannot get things hot enough to really taste right. A cup of tea that you can stir with your finger is simply not worth drinking.<br />
<br />
Also low air pressure will not support as thick a layer of protecting regolith over inflated buildings.<br />
<br />
===Supporting Regolith===<br />
<br />
Here are some of present ideas for lunar settlement air pressures and how much regolith they will support:<br />
<br />
<br />
{| border=1<br />
! colspan="2" | Pressure !! colspan="2" | Boiling Point Of Water !! Regolith Needed to Equal Atmospheric Shielding !! Maximum Regolith Supported !!Comment<br />
|-<br />
| kPa || psi || °C || °F || m || m ||<br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || 5.4 || 32 || Sea Level, ISS body<br />
|-<br />
| 84 || 12.17 || 95 || 203 || 4.5 || 27 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || 4.3 || 26 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || 4.0 || 24 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || 3.2 || 19 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || 1.8 || 10 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || 1.6 || 9.9 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || 1.4 || 8.4 || Top of Mount Everest<br />
|-<br />
| 10.0 || 1.5 || 46 || 115 || 0.5 || 3.2 || 1/10 Atm, 16,000 m, unconscious in 10 sec<br />
|}<br />
<br />
The Regolith Shield column shows how much lunar regolith is needed to provide radiation shielding equivalent to the air above your head at these locations on Earth. The Regolith Support column shows how much lunar regolith can be supported on the Moon by that level of internal pressure.<br />
<br />
These calculations are based on the following parameters:<br />
<br />
{| border=1<br />
| density of packed regolith || 1.9 || g/cm^3 || Used for this calculation<br />
|-<br />
| density of loose regolith || 1.5 || g/cm^3 || just poured in a pile<br />
|-<br />
| Lunar gravity || 1.63 || m/s^2 || about 1/6 Earth<br />
|-<br />
| Human body temperature || 37.0 || C || 98.6 F<br />
<br />
|}<br />
<br />
<br />
It is important to note that the internal pressure inside a living area has plenty of force to support a substantial thickness of lunar regolith above it for radiation and thermal shielding even if low pressures are used.<br />
<br />
<br />
<br />
{{Hazards}}<br />
<br />
<br />
[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Talk:Roof_Support&diff=16543Talk:Roof Support2011-09-02T10:24:08Z<p>Silverwurm: </p>
<hr />
<div>Having a inflated building covered with regolith for radiation and thermal protection is very attractive but it has its own special dangers too.<br />
<br />
--[[User:207.114.17.95|207.114.17.95]] 12:18, 27 May 2007 (UTC)<br />
<br />
----<br />
<br />
I have a thin lead on a publisher interested in the Lunar Settlement story environment To support this effort, I will now proof read and up date the technical articles that support the stories. Please email me for more information.<br />
<br />
I think it a good idea to move these entries (Architecture as Mole Hills, Roof Support, etc.) over to the Scientifiction section and present them as a story environment I do not know how to do the necessary editing.<br />
<br />
--[[User:Jriley|Jriley]] 13:30, 31 May 2009 (UTC)<br />
----<br />
<br />
I'm going to move the discussion on internal pressure considerations (high vs low pressure) to a separate page. This page is specifically about roof support. <BR/>-- [[User:Silverwurm|Silverwurm]] 10:24, 2 September 2011 (UTC)</div>Silverwurmhttps://lunarpedia.org/index.php?title=Roof_Support&diff=16542Roof Support2011-09-02T10:21:03Z<p>Silverwurm: Reworked page structure, significant rewording and editing of multiple entries</p>
<hr />
<div>__TOC__<br />
<br />
[[Image:ArchDorm01.jpg|frame| [[Architecture as Mole Hills]], Standard dorm room]]<br />
==Introduction==<br />
Structural support in lunar habitats will be quite different from earth based buildings. One primary difference is that, due to the need for lunar habitats to maintain a sizable internal pressure, most of the standard operating stresses will be internal rather than external.<br />
<br />
<br />
== Safety considerations ==<br />
<br />
Most proposals for long term lunar habitats call for the use of a thick blanket of lunar regolith to be piled atop the structure, providing protection from temperature swings, meteorite impacts, and cosmic radiation for the inhabitant, as well as any electronic equipment (see [[Architecture as Mole Hills]] and [[Architecture as Tent City]]).<br />
<br />
Most of the experience mankind has accumulated concerning radiation deals with nuclear radiation. The cosmic radiation encountered beyond earths magnetic field is much less understood, as it can only be replicated on earth by means of a particle accelerator. As such, the question of how much regolith is needed to protect the inhabitants is currently little more than educated guesswork, and will likely remain so until more thorough field study is performed.<br />
<br />
One common estimation is to provide enough regolith to equal earths atmosphere in shielding potential. This is based on the fact that the earths magnetic field has collapsed several times in geologic history, and said collapses did not seem to have any major effect on the life on earth. As such, it is believed that the mass of earths atmosphere is by itself sufficient to guard against cosmic radiation. Assuming that air and lunar regolith have similar shielding properties according to their mass (as they do for nuclear radiation), this gives several different thicknesses, depending on what altitude is used for comparison.<br />
<br />
{| border=1<br />
! Location !! colspan="2" | Atmospheric Pressure !! colspan="2" | Regolith Needed to Equal Atmospheric Shielding !! colspan="2" | Miniumum Internal Pressure Required<br />
|-<br />
| || kPa || psi || m || f || kPa || psi<br />
|-<br />
| Sea Level || 101.3 || 14.2 || 5.4 || 17.9 || 16.9 || 2.4<br />
|-<br />
| Denver a high altitude city || 84 || 12.17 || 4.5 || 14.8 || 14 || 2<br />
|-<br />
| Mexico City, a high altitude city || 81.4 || 11.74 || 4.4 || 14.3 || 13.5 || 2<br />
|-<br />
| Open airplane || 74.0 || 10.2 || 4.0 || 13 || 12.3 || 1.8<br />
|-<br />
| Top of Mount Everest || 26.0 || 3.65 || 1.4 || 4.6 || 4.3 || 0.6<br />
|}<br />
<br />
(assuming a regolith density of 1.9 grams/cm^3 and lunar gravitation acceleration of 1.63 m/s^2)<br />
<br />
As seen from the chart, the minimum habitat pressure level needed to support the regolith shield on pressure alone is quite low, even for sea level equivalent shielding. As such, a structure pressurized to sea level pressure (like the ISS), and covered with enough regolith equal sea level radiation shielding would have a large net force pushing outward. The reason for this is that, though the regolith piled atop the structure is the same mass per unit area as earths atmosphere would be, lunar gravity is only around 1/6 of earths, resulting in much less force pushing downward, but the same pressure pushing upward. If the same structure was constructed in earth-like gravity (but still in a vacuum), the pressure would be equal.<br />
<br />
As a result, lunar habitat functioning under normal parameters would not require any internal support for its main structure, as the internal forces are greater. A lunar habitat could therefor be essentially a giant, reinforced balloon, covered in lunar regolith.<br />
<br />
===Depressurization===<br />
One safety consideration for such a structure is to plan for operation in case of pressure loss, also known as a blow out. Some mechanism of coping with a blow out would be required.<br />
<br />
One method of dealing with a blowout is to make the outer structure sufficiently strong that it will not only keep in the pressure under normal conditions, but will also hold its own in a depressurized state. As seen in the chart, a structure capable of supporting a sea level equivalent regolith shield under depressurized conditions would be subject to just under 3 psi of pressure across its roof. This is approximately equivalent to designing an earthbound structure capable of maintaining twice atmospheric pressure under normal conditions, and standard atmospheric pressure six feet underwater in an emergency. A [[steel]] or [[titanium]] structure could be made sufficiently strong to withstand these forces, as could a properly designed [[Sintered Brick Construction|lunar brick]] structure reinforced with steel cable.<br />
<br />
A structure which was supported only by internal pressure would require additional mechanisms to ensure the safety of its inhabitants in case of a blowout. One way of coping with this is to compartmentalize the structure, or in other words, design it so that separate areas could be sealed off if needed, so that a breach in one area would not affect the entire habitat. An additional safety measure that could be installed is a series of gas tanks linked to different areas of the habitat. In the event of a breach, gas could be fed in to maintain the pressure in the affected area long enough to evacuate it.<br />
<br />
It has been suggested that a structure incapable of holding its own in a depressurized state would need to be designed to allow a person wearing an environmental suit enough clearance to crawl to safety even if a second person is lying immobile in the evacuation path. It has been further suggested that this would lead to small rooms being prevalent in these types of structures, as they are much easier to reinforce against collapse. As such, building large rooms in a lunar environment would require the use of structures that do not require internal pressurization to remain standing.<br />
<br />
==Pressure Considerations==<br />
<br />
<br />
One of the most important considerations in the design of a lunar settlement will be the internal air pressure.<br />
<br />
===High Pressure===<br />
<br />
High air pressure, that is Earth normal 101 kpa (14.2 PSI, makes the living space more Earth like. People and plants accommodate to living on the Moon easily and food is easy to cook.<br />
<br />
But, spacesuits must be at low pressure for the joints to work with acceptable amounts of efforts. Any time a persons moves from a high pressure to a low pressure environment, you risk nitrogen forming bubbles in your blood; a conditions called the bends. For the body to accommodate from normal air pressure to a low spacesuit pressure can take as long as an overnight stay in a low pressure chamber.<br />
<br />
===Low Pressure===<br />
<br />
Low air pressure, with adequate oxygen content, allows the human body to accommodation to spacesuit pressures in only a few minutes or just seconds in an emergency. Ranges from 74 kPa (10.2 psi) down to 33.5 kpi (4.7 psi) have been discussed for lunar settlements. The human body will simply never fully accommodate pressures below about 30 kPascal (4.2 psi). <br />
<br />
At low pressures you can use 100% oxygen which greatly simplifies the entire life support system. Testing this type of system is very dangerous and has resulted in two serious fires. The key safety concept is that if the partial pressure of oxygen exceeds Earth normal of 22 kPascal (3.0 psi) then substancial fire control efforts are required.<br />
<br />
The long term health effects of low pressure are not fully known for people or for plants. Any agricultural areas may need additional CO2, humidity, and nitrogen compared the people living areas. <br />
<br />
Low pressure also saves the cost of shipping a large mass of bulk nitrogen from Earth. This could be a very important cost consideration in early lunar settlements.<br />
<br />
Water boils at such a low temperature at low atmospheric pressure that cooking is difficult. You simply cannot get things hot enough to really taste right. A cup of tea that you can stir with your finger is simply not worth drinking.<br />
<br />
Also low air pressure will not support as thick a layer of protecting regolith over inflated buildings.<br />
<br />
===Supporting Regolith===<br />
<br />
Here are some of present ideas for lunar settlement air pressures and how much regolith they will support:<br />
<br />
<br />
{| border=1<br />
! colspan="2" | Pressure !! colspan="2" | Boiling Point Of Water !! Regolith Needed to Equal Atmospheric Shielding !! Maximum Regolith Supported !!Comment<br />
|-<br />
| kPa || psi || °C || °F || m || m ||<br />
|-<br />
| 101.3 || 14.2 || 100 || 212 || 5.4 || 32 || Sea Level, ISS body<br />
|-<br />
| 84 || 12.17 || 95 || 203 || 4.5 || 27 || Denver, a high altitude city<br />
|-<br />
| 81.4 || 11.74 || 94 || 201 || 4.3 || 26 || Mexico City, a high altitude city<br />
|-<br />
| 74.0 || 10.2 || 92 || 197 || 4.0 || 24 || Open airplane, ISS ports<br />
|-<br />
| 59.1 || 8.3 || 86 || 187 || 3.2 || 19 || ISS spacesuit<br />
|-<br />
| 33.5 || 4.7 || 72 || 162 || 1.8 || 10 || Apollo spacesuit<br />
|-<br />
| 30.6 || 4.3 || 70 || 158 || 1.6 || 9.9 || Shuttle spacesuit<br />
|-<br />
| 26.0 || 3.65 || 66 || 152 || 1.4 || 8.4 || Top of Mount Everest<br />
|-<br />
| 10.0 || 1.5 || 46 || 115 || 0.5 || 3.2 || 1/10 Atm, 16,000 m, unconscious in 10 sec<br />
|}<br />
<br />
The Regolith Shield column shows how much lunar regolith is needed to provide radiation shielding equivalent to the air above your head at these locations on Earth. The Regolith Support column shows how much lunar regolith can be supported on the Moon by that level of internal pressure.<br />
<br />
These calculations are based on the following parameters:<br />
<br />
{| border=1<br />
| density of packed regolith || 1.9 || g/cm^3 || Used for this calculation<br />
|-<br />
| density of loose regolith || 1.5 || g/cm^3 || just poured in a pile<br />
|-<br />
| Lunar gravity || 1.63 || m/s^2 || about 1/6 Earth<br />
|-<br />
| Human body temperature || 37.0 || C || 98.6 F<br />
<br />
|}<br />
<br />
<br />
It is important to note that the internal pressure inside a living area has plenty of force to support a substantial thickness of lunar regolith above it for radiation and thermal shielding even if low pressures are used.<br />
<br />
<br />
<br />
{{Hazards}}<br />
<br />
<br />
[[Category:Architecture]]<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16540Lunar Settlement Artificial Atmosphere2011-09-01T23:44:41Z<p>Silverwurm: /* Gas Combination */</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Gas Combination ==<br />
<sub>See also: [[Atmosphere]]</sub><br />
<br />
[[Oxygen]] is expected to be a major by-product of [[manufacturing activities]] on the moon. As such, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. A pure oxygen atmosphere also carries the advantages of allowing a much lower habitat pressure, and greatly simplifying the machinery needed to maintain the atmospheric mix. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, as well as the early designs of the Apollo spacecraft. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> <br />
<br />
A combination of one or more [[inert gases]] with Oxygen would allow proper oxygenation over longer time-frames. A [[nitrogen]]-[[oxygen]] mix could be utilized, as it is in earths atmosphere, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. [[Helium]] could also be added to the oxygen mix, as it is significantly more abundant in lunar soil, and its low density means significantly less mass is required for a given volume. However, the addition of any appreciable quantities of helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
== Lower Pressure ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref> and Humans can live in lower pressure atmospheres properly oxygenated. The limit is clear: when the vapor of a liquid inside equals the pressure outside, the liquid boils. Blood and other body fluids will boil if an abrupt drop of the pressure occurs.<br />
<br />
We would need to lower the pressure inside the buildings to lower the force applied to the walls (somewhere around 40kPa would be ideal for many structures). Also, precise atmospheric pressure controls would be needed to prevent gas leaking.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16539Lunar Settlement Artificial Atmosphere2011-09-01T23:43:08Z<p>Silverwurm: /* Gas Combination */</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Gas Combination ==<br />
<sub>See also: [[Atmosphere]]</sub><br />
<br />
[[Oxygen]] is expected to be a major by-product of [[manufacturing activities]] on the moon. As such, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. A pure oxygen atmosphere also carries the advantages of allowing a much lower habitat pressure, and greatly simplifying the machinery needed to maintain the atmospheric mix. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, as well as the early designs of the Apollo spacecraft. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> <br />
<br />
A combination of one or more [[inert gases]] with Oxygen would allow proper oxygenation over longer time-frames. A [[nitrogen]]-[[oxygen]] mix could be utilized, as it is in earths atmosphere, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. [[Helium]] could also be added to the oxygen mix, as it is significantly more abundant in lunar soil. However, the addition of any appreciable quantities of helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
== Lower Pressure ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref> and Humans can live in lower pressure atmospheres properly oxygenated. The limit is clear: when the vapor of a liquid inside equals the pressure outside, the liquid boils. Blood and other body fluids will boil if an abrupt drop of the pressure occurs.<br />
<br />
We would need to lower the pressure inside the buildings to lower the force applied to the walls (somewhere around 40kPa would be ideal for many structures). Also, precise atmospheric pressure controls would be needed to prevent gas leaking.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16538Lunar Settlement Artificial Atmosphere2011-09-01T23:41:26Z<p>Silverwurm: /* Introduction */</p>
<hr />
<div>== Introduction ==<br />
A lunar habitat will require a pressurized mixture of gasses to sustain the life of the inhabitants. There is some experimental data with some artificial atmospheres, mostly from space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. These stations have been manned by human crew for extended periods of time. However, projected lunar habitats will manned for longer time frames, and more experimentation will be required on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables include the use of [[Air Lock]]s, the thickness and materials of the walls, and other variables.<br />
<br />
== Gas Combination ==<br />
<sub>See also: [[Atmosphere]]</sub><br />
<br />
Oxygen is expected to be a major by-product of [[manufacturing activities]] on the moon. As such, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. A pure oxygen atmosphere also carries the advantages of allowing a much lower habitat pressure, and greatly simplifying the machinery needed to maintain the atmospheric mix. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, as well as the early designs of the Apollo spacecraft. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> <br />
<br />
A combination of one or more [[inert gases]] with Oxygen would allow proper oxygenation over longer time-frames. A nitrogen-oxygen mix could be utilized, as it is in earths atmosphere, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. Helium could also be added to the oxygen mix, as it is significantly more abundant in lunar soil. However, the addition of any appreciable quantities of Helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
== Lower Pressure ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref> and Humans can live in lower pressure atmospheres properly oxygenated. The limit is clear: when the vapor of a liquid inside equals the pressure outside, the liquid boils. Blood and other body fluids will boil if an abrupt drop of the pressure occurs.<br />
<br />
We would need to lower the pressure inside the buildings to lower the force applied to the walls (somewhere around 40kPa would be ideal for many structures). Also, precise atmospheric pressure controls would be needed to prevent gas leaking.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Settlement_Artificial_Atmosphere&diff=16537Lunar Settlement Artificial Atmosphere2011-09-01T23:37:47Z<p>Silverwurm: </p>
<hr />
<div>== Introduction ==<br />
The lunar colony will have a pressurized selection of acceptable gaseous environments. We have experimental knowledge with some artificial atmospheres,say, space stations like [[ISS into the Pacific|ISS]] or the [[MIR]]. Yet, we need to experiment more on the effects of long term exposure. On the Moon, the atmosphere will be made in accordance with the architecture followed. Some variables like the use of [[Air Lock]]s, the thickness and materials of the walls may change the gas composition, pressure and other variables.<br />
<br />
== Gas Combination ==<br />
<sub>See also: [[Atmosphere]]</sub><br />
<br />
Oxygen is expected to be a major by-product of [[manufacturing activities]] on the moon. As such, a pure oxygen atmosphere is attractive as it is likely to be the easiest (and hence, cheapest) gas to procure on the moon. A pure oxygen atmosphere also carries the advantages of allowing a much lower habitat pressure, and greatly simplifying the machinery needed to maintain the atmospheric mix. For these reasons, a pure oxygen atmosphere was utilized in the Gemini project, as well as the early designs of the Apollo spacecraft. However, some studies suggest that a pure oxygen atmosphere becomes poisonous to the inhabitants on long term exposure, making it unsuitable for a lunar habitat.<ref>Malina, Frank J., ed. Life Science Research and Lunar Medicine. London: A. Wheathon and Co. Ltd. 1967 pg. 3-4 </ref> <br />
<br />
A combination of one or more [[inert gases]] with Oxygen would allow proper oxygenation over longer time-frames. A nitrogen-oxygen mix could be utilized, as it is in earths atmosphere, though the low availability of nitrogen in lunar soil (compared to other [[volatiles]]) could raise difficulties in this regard. Helium could also be added to the oxygen mix, as it is significantly more abundant in lunar soil. However, the addition of any appreciable quantities of Helium to the atmosphere would result in a higher vocal pitch for those persons breathing it, similar to (though less intense than) the effects of inhaling pure helium. This effect is currently seen on earth in very deep diving operations, where helium-oxygen mixes are utilized, sometimes facilitating the need for a digital voice alteration device.<br />
<br />
== Lower Pressure ==<br />
<br />
Plants <ref>Henninger, D. L., ed. Lunar Base Agriculture. Texas: NASA & Soil Science Society of America. ISBN 0- 89118-100-8 Introduction</ref> and Humans can live in lower pressure atmospheres properly oxygenated. The limit is clear: when the vapor of a liquid inside equals the pressure outside, the liquid boils. Blood and other body fluids will boil if an abrupt drop of the pressure occurs.<br />
<br />
We would need to lower the pressure inside the buildings to lower the force applied to the walls (somewhere around 40kPa would be ideal for many structures). Also, precise atmospheric pressure controls would be needed to prevent gas leaking.<br />
<br />
== See Also ==<br />
*[[Atmosphere]]<br />
*[[Lunar Atmosphere]]<br />
*[[Lunar Life Support Parameters]]<br />
*[[Lunar Settlement]]<br />
<br />
== References ==<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Architecture&diff=16536Lunar Architecture2011-09-01T23:36:17Z<p>Silverwurm: /* Thermal Protection */</p>
<hr />
<div>__TOC__<br />
<br />
== Introduction ==<br />
The architecture used on Luna will be quite different from that used in terrestrial applications. Lower gravity, high vacuum, radiation, meteorites, [[moonquake|moonquakes]], and dust control will all play large parts in the design of lunar structures. Due to this, a large number of architectural designs have been put forward for human rated habitats on Luna.<br />
<br />
== Major Design Criteria ==<br />
<br />
=== Atmospheric Control ===<br />
(see also [[Lunar Settlement Artificial Atmosphere]])<br />
<br />
Any lunar habitat designed for human use must provide a breathable atmosphere and maintain proper carbon dioxide, temperature, and humidity levels. There are a number of methods proposed for achieving this, as well as number of proposals for suitable gas mixtures and pressures.<br />
<br />
=== Thermal Protection ===<br />
The lack of an atmosphere on the moon, together with the extreme duration of the lunar day/night cycle, leads to large temperature extremes. A lunar habitat would need to provide a reasonably constant temperature inside.<br />
<br />
The most commonly proposed solution to this problem is a blanket of lunar regolith piled over the habitat. Lunar regolith has extremely low thermal conductivity, and as little as a few inches would protect the habitat from any temperature swings that would be experienced outside<ref name='Lindsey'>Lindsey, Nancy J. [http://www.rcktmom.com/njlworks/LunarRegolithPprenvi2.html Lunar Station Protection: Lunar Regolith Shielding]. International Lunar Conference 2003</ref>. This solution has an advantage in that lunar regolith is readily available anywhere on the moons surface. The downside is that moving a sufficient amount of regolith to cover a lunar structure would require construction equipment on site, which may not be available for an initial lunar base attempt.<br />
<br />
More conventional insulation could be used in this case as well. Due to the vacuum conditions on the moons surface, a reflective coating applied to the surface of the habitat would provide reasonably good thermal protection, functioning in a similar manner to a thermos. This coating would reflect solar radiation during the day, and preventing radiation of internal heat at night. Multiple reflective baffles installed at the surface would increase the effect. To date, this approach has been utilized on all lunar missions, all of which took place during the lunar day and near the equator.<br />
<br />
Even if the insulation was sufficient to block out the temperature variations, some additional cooling would be required, as energy would be continuously be generated within the habitat from electrical equipment and the metabolic processes of the inhabitants. Insulation sufficient to block out heat from outside would, on the same token, keep heat inside. A series of external radiators, suitably placed so as to be out of the sun during the day, could provide the necessary cooling.<br />
<br />
=== Meteorites ===<br />
A lunar habitat would need to be protected from meteorite impacts. This requirement is similar to the requirements already in place on orbital structures such as the ISS. One significant difference is that orbital structures have a certain amount of maneuvering capability to dodge incoming debris, while a lunar habitat does not. As such lunar structures have more stringent requirements than orbital structures for impact protection.<br />
<br />
The solution to this problem most commonly suggested is the same as for thermal protection, namely, a blanket of lunar regolith. This blanket would need to be thicker than what is required for thermal protection, though a thickness of less than half a meter is considered to be sufficient<ref name='Lindsey'> </ref>. This again carries the requirement of having construction equipment on site.<br />
<br />
Other shielding technologies could be utilized to provide sufficient meteorite protection. Inflatable spacecraft designs in particular show promise in this regard. Bigelow aerospace is developing a line of these structures, a derivative of the cancelled NASA TransHab project. Bigelow has already flown two prototypes of this technology, and intends to construct a privatelly owned space station with them, as well as an eventual moonbase. The company claims that the meteorite shielding material built into its modules is sufficient for this purpose.<br />
<br />
=== Radiation ===<br />
One of the more difficult problems facing design of a lunar habitat is protection from solar and cosmic radiation. The moon, being outside the earths magnetic field, receives this radiation directly. Of particular importance is the effect of solar storms, a single one of which would provide sufficient radiation to kill an unprotected person.<br />
<br />
The regolith blanket proposed as protection from thermal and meteorite hazards could also serve the third function of radiation protection, given sufficient thickness. How thick this shield would need to be is a matter of some debate, as the exact level of safe radiation is not entirely agreed upon. To reduce the radiation levels received to current NASA standards for its astronauts, a thickness of 1-2 meters appears to be sufficient<ref name="Lindsey"> </ref>. If earth-like levels are desired, then 3-5 meters would likely be needed. The exact thickness is not precisely known, due to the differences between cosmic radiation and the nuclear radiation most shielding science is designed to protect against, and most likely will remain an educated guess until a more in-depth field study is made.<br />
<br />
If equipment for moving a sufficient amount of lunar regolith is not available on site (an early base construction attempt for example), providing sufficient shielding is difficult matter. One option is to site the base in of the the permanently shaded polar craters, where solar storms would not reach. Another is to provide a "storm cellar" of sorts, a small room in the habitat which is heavily shielded against radiation, which the crew could retreat into in case of a solar storm. As this room would only need to be big enough to hold the crew until the radiation levels dropped back to normal, its construction and shipping to the base site would be much simpler than shielding the entire habitat, which could make it a viable solution for an early base attempt.<br />
<br />
=== Moonquakes ===<br />
(see main article: [[Moonquake]])<br />
<br />
Moonquakes are moderately powerful (by earth standards) seismic events which can last for over ten minutes. Habitats placed in areas where moonquakes occur will need to be sufficiently strong/flexible to withstand the shaking without buckling or leaking atmosphere.<br />
<br />
== Proposed Designs ==<br />
;[[Architecture as Mole Hills]]: The living space could be inflated structures buried in trenches.<br />
<br />
;[[Architecture as Tent City]]: We could use tents to protect inflated living space.<br />
<br />
;[[Architecture in Field Stone]]: The loose rocks of the Moon could provide the needed thermal and radiation protection.<br />
<br />
==See Also==<br />
*[[Meteor Hazards]]<br />
*[[Radiation Problem]]<br />
*[[Roof Support]]<br />
*[[Power for Settlements]]<br />
*[[Site Selection]]<br />
*[[Slopes]]<br />
<br />
==References==<br />
<references/><br />
<br />
[[Category:Architecture]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Moonquake&diff=16535Moonquake2011-09-01T23:32:54Z<p>Silverwurm: /* Intensity */</p>
<hr />
<div>Moonquakes are the lunar analog to terrestrial earthquakes. Though generally not as great in magnitude as terrestrial earthquakes, they could pose difficulty in the construction of long term lunar habitats.<br />
<br />
<br />
== Types of Moonquakes ==<br />
<br />
Seismometers were left by Apollo astronauts at their landing sites between 1969 and 1972. These devices remained functional until their deactivation in 1977. During that time, at least four different types of lunar quakes were observed.<br />
<br />
===Deep Moonquakes===<br />
These quakes were found to originate quite deep (around 700 km), and are theorized to be caused by tidal interactions with the earth.<br />
<br />
===Impact Vibrations===<br />
Quakes caused by the impact of lunar meteorites.<br />
<br />
===Thermal Quakes===<br />
Caused by thermal expansion of the crust after the lunar night ends and the surface is warmed by the sun.<br />
<br />
===Shallow Moonquakes===<br />
These quakes originate 20-30 kilometers below the surface. Their exact cause is unknown, though slumping of young crater rims is suggested as a possible explanation.<br />
<br />
===Intensity===<br />
Deep Moonquakes, Impact Vibrations, and Thermal Quakes were all found to be quite mild. Shallow Moonquakes on the other hand could be much more intense, as much as 5.5 on the Richter scale. Furthermore, once a shallow moonquake began, it would persist for over ten minutes. This is explained by the lack of chemical weathering on the moon. On earth, chemical weathering has created weaknesses in the surface, causing it to act as as sponge, absorbing vibrations quite effectively. On the moon, the surface behaves more like a solid chuck of rock, and takes significantly longer to absorb the vibrations. Between 1972 and 1977, the Apollo seismometers recorded twenty eight shallow moonquakes.<br />
<br />
== Effect on Lunar Colonization ==<br />
<br />
A shallow moonquake could spell doom for a poorly designed lunar habitat. Of importance is not only the magnitude of these quakes, but their exceptionally long duration. No earth structure has ever needed to be designed to handle this kind of scenario. Structures would have to be sufficiently strong / flexible to survive this shaking without buckling or leaking atmosphere, and internal furnishings/equipment would need to be secured against the significant motion that would occur from such a long lasting quake. It has been suggested that [[aluminum]] would be unsuitable for structural components under these circumstances, as it lacks a well defined fatigue limit, and will fail from even small vibrations given sufficient time. [[Iron]] and [[titanium]] fare much better in this regard. Buildings composed of [[Sintered Regolith|lunar brick]] would need especially careful planning to avoid fractures, and may in fact be impractical in high quake areas. NASA has proposed placing additional seismometers on the lunar surface in order to better map quake occurrence, and perhaps find areas which are more stable.<br />
<br />
<br />
<br />
== External Links ==<br />
[http://science.nasa.gov/science-news/science-at-nasa/2006/15mar_moonquakes/ NASA Article On Moonquakes]<br />
<br />
[http://en.wikipedia.org/wiki/Fatigue_limit Wikipedia Article on Fatigue Limit]<br />
<br />
[http://www.earthmagazine.org/earth/article/24d-7d9-8-13 EARTH Magazine Article on Deep Moonquakes]<br />
<br />
<br />
[[Category:Hazards]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Architecture&diff=16534Lunar Architecture2011-09-01T23:31:39Z<p>Silverwurm: Expanded page, moved much of previous list to its own section, added reference</p>
<hr />
<div>__TOC__<br />
<br />
== Introduction ==<br />
The architecture used on Luna will be quite different from that used in terrestrial applications. Lower gravity, high vacuum, radiation, meteorites, [[moonquake|moonquakes]], and dust control will all play large parts in the design of lunar structures. Due to this, a large number of architectural designs have been put forward for human rated habitats on Luna.<br />
<br />
== Major Design Criteria ==<br />
<br />
=== Atmospheric Control ===<br />
(see also [[Lunar Settlement Artificial Atmosphere]])<br />
<br />
Any lunar habitat designed for human use must provide a breathable atmosphere and maintain proper carbon dioxide, temperature, and humidity levels. There are a number of methods proposed for achieving this, as well as number of proposals for suitable gas mixtures and pressures.<br />
<br />
=== Thermal Protection ===<br />
The lack of an atmosphere on the moon, together with the extreme duration of the lunar day/night cycle, leads to large temperature extremes. A lunar habitat would need to provide a reasonably constant temperature inside.<br />
<br />
The most commonly proposed solution to this problem is a blanket of lunar regolith piled over the habitat. Lunar regolith has extremely low thermal conductivity, and as little as a few inches would protect the habitat from any temperature swings that would be experienced outside<ref name='Lindsey'>http://www.rcktmom.com/njlworks/LunarRegolithPprenvi2.html</ref>. This solution has an advantage in that lunar regolith is readily available anywhere on the moons surface. The downside is that moving a sufficient amount of regolith to cover a lunar structure would require construction equipment on site, which may not be available for an initial lunar base attempt.<br />
<br />
More conventional insulation could be used in this case as well. Due to the vacuum conditions on the moons surface, a reflective coating applied to the surface of the habitat would provide reasonably good thermal protection, functioning in a similar manner to a thermos. This coating would reflect solar radiation during the day, and preventing radiation of internal heat at night. Multiple reflective baffles installed at the surface would increase the effect. To date, this approach has been utilized on all lunar missions, all of which took place during the lunar day and near the equator.<br />
<br />
Even if the insulation was sufficient to block out the temperature variations, some additional cooling would be required, as energy would be continuously be generated within the habitat from electrical equipment and the metabolic processes of the inhabitants. Insulation sufficient to block out heat from outside would, on the same token, keep heat inside. A series of external radiators, suitably placed so as to be out of the sun during the day, could provide the necessary cooling.<br />
<br />
=== Meteorites ===<br />
A lunar habitat would need to be protected from meteorite impacts. This requirement is similar to the requirements already in place on orbital structures such as the ISS. One significant difference is that orbital structures have a certain amount of maneuvering capability to dodge incoming debris, while a lunar habitat does not. As such lunar structures have more stringent requirements than orbital structures for impact protection.<br />
<br />
The solution to this problem most commonly suggested is the same as for thermal protection, namely, a blanket of lunar regolith. This blanket would need to be thicker than what is required for thermal protection, though a thickness of less than half a meter is considered to be sufficient<ref name='Lindsey'> </ref>. This again carries the requirement of having construction equipment on site.<br />
<br />
Other shielding technologies could be utilized to provide sufficient meteorite protection. Inflatable spacecraft designs in particular show promise in this regard. Bigelow aerospace is developing a line of these structures, a derivative of the cancelled NASA TransHab project. Bigelow has already flown two prototypes of this technology, and intends to construct a privatelly owned space station with them, as well as an eventual moonbase. The company claims that the meteorite shielding material built into its modules is sufficient for this purpose.<br />
<br />
=== Radiation ===<br />
One of the more difficult problems facing design of a lunar habitat is protection from solar and cosmic radiation. The moon, being outside the earths magnetic field, receives this radiation directly. Of particular importance is the effect of solar storms, a single one of which would provide sufficient radiation to kill an unprotected person.<br />
<br />
The regolith blanket proposed as protection from thermal and meteorite hazards could also serve the third function of radiation protection, given sufficient thickness. How thick this shield would need to be is a matter of some debate, as the exact level of safe radiation is not entirely agreed upon. To reduce the radiation levels received to current NASA standards for its astronauts, a thickness of 1-2 meters appears to be sufficient<ref name="Lindsey"> </ref>. If earth-like levels are desired, then 3-5 meters would likely be needed. The exact thickness is not precisely known, due to the differences between cosmic radiation and the nuclear radiation most shielding science is designed to protect against, and most likely will remain an educated guess until a more in-depth field study is made.<br />
<br />
If equipment for moving a sufficient amount of lunar regolith is not available on site (an early base construction attempt for example), providing sufficient shielding is difficult matter. One option is to site the base in of the the permanently shaded polar craters, where solar storms would not reach. Another is to provide a "storm cellar" of sorts, a small room in the habitat which is heavily shielded against radiation, which the crew could retreat into in case of a solar storm. As this room would only need to be big enough to hold the crew until the radiation levels dropped back to normal, its construction and shipping to the base site would be much simpler than shielding the entire habitat, which could make it a viable solution for an early base attempt.<br />
<br />
=== Moonquakes ===<br />
(see main article: [[Moonquake]])<br />
<br />
Moonquakes are moderately powerful (by earth standards) seismic events which can last for over ten minutes. Habitats placed in areas where moonquakes occur will need to be sufficiently strong/flexible to withstand the shaking without buckling or leaking atmosphere.<br />
<br />
== Proposed Designs ==<br />
;[[Architecture as Mole Hills]]: The living space could be inflated structures buried in trenches.<br />
<br />
;[[Architecture as Tent City]]: We could use tents to protect inflated living space.<br />
<br />
;[[Architecture in Field Stone]]: The loose rocks of the Moon could provide the needed thermal and radiation protection.<br />
<br />
==See Also==<br />
*[[Meteor Hazards]]<br />
*[[Radiation Problem]]<br />
*[[Roof Support]]<br />
*[[Power for Settlements]]<br />
*[[Site Selection]]<br />
*[[Slopes]]<br />
<br />
==References==<br />
<references/><br />
<br />
[[Category:Architecture]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Architecture&diff=16530Lunar Architecture2011-09-01T21:14:46Z<p>Silverwurm: moved Architecture List to Lunar Architecture: This page will be expanded to be more than a list, lunar architecture seemed more appropriate</p>
<hr />
<div>{|align=right<br />
|__TOC__<br />
|}<br />
<br />
<font size=5> A listing of Lunar Architecture Entries </font><br />
<br />
----<br />
<br />
There are many ways we could go about building a lunar base. Here are just a few of them along with some critical design considerations.<br />
<br />
----<br />
<br />
==Architectures==<br />
<br />
<br />
;[[Architecture as Mole Hills]]: The living space could be inflated structures buried in trenches.<br />
<br />
;[[Architecture as Tent City]]: We could use tents to protect inflated living space.<br />
<br />
;[[Architecture in Field Stone]]: The loose rocks of the Moon could provide the needed thermal and radiation protection.<br />
<br />
==Supporting Architecture==<br />
<br />
<br />
Here are a few ideas on building lunar settlements.<br />
<br />
<br />
;[[Meteor Hazards]]: Things can fall on your head.<br />
<br />
;[[Radiation Problem]]: Protections we take for granted on Earth must be intentionally provided.<br />
<br />
;[[Roof Support]]: Can the internal air pressure support the roof?<br />
<br />
;[[Power for Settlements]]: Electrical power is the key to survival.<br />
<br />
;[[Site Selection]]: Choosing a good site may be the most important decision you have to make.<br />
<br />
;[[Slopes]]: Nothing on the Moon is truly flat.<br />
<br />
<br />
<br />
----<br />
<br />
<br />
[[Category:Architecture]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Talk:Lunar_Architecture&diff=16532Talk:Lunar Architecture2011-09-01T21:14:46Z<p>Silverwurm: moved Talk:Architecture List to Talk:Lunar Architecture: This page will be expanded to be more than a list, lunar architecture seemed more appropriate</p>
<hr />
<div>There are a lot of ways to build a settlement on the Moon.<br />
<br />
--[[User:Jriley|Jriley]] 12:26, 15 September 2007 (UTC)<br />
<br />
----</div>Silverwurmhttps://lunarpedia.org/index.php?title=Talk:Architecture_List&diff=16533Talk:Architecture List2011-09-01T21:14:46Z<p>Silverwurm: moved Talk:Architecture List to Talk:Lunar Architecture: This page will be expanded to be more than a list, lunar architecture seemed more appropriate</p>
<hr />
<div>#REDIRECT [[Talk:Lunar Architecture]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16527In-Situ Propellant Production2011-08-29T03:15:35Z<p>Silverwurm: /* Sulfur */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. The specific impulse of silane is slightly less than methane, and would use slightly less hydrogen for a given launch weight.<br />
<br />
Silane holds an advantage over methane as silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, in what is sometimes referred to as a "Brimstone Rocket". Sulfur melts at about 115 °C, which could be easily achieved by preheating the fuel tank before launch. Burning this molten sulfur with liquid oxygen would produce sulfur dioxide as exhaust, with a specific impulse of around 285 seconds. Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon, some mare soils containing as much as .27% by weight.<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16526In-Situ Propellant Production2011-08-29T03:08:36Z<p>Silverwurm: /* Sulfur */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. The specific impulse of silane is slightly less than methane, and would use slightly less hydrogen for a given launch weight.<br />
<br />
Silane holds an advantage over methane as silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, burning it with liquid oxygen to produce sulfur dioxide exhaust, referred to by some as a "Brimstone Rocket". Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon(as much as .27% in some mare soils), making it much easier to extract. The expected specific impulse is around 285 seconds<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16525In-Situ Propellant Production2011-08-29T03:05:42Z<p>Silverwurm: /* Sulfur */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. The specific impulse of silane is slightly less than methane, and would use slightly less hydrogen for a given launch weight.<br />
<br />
Silane holds an advantage over methane as silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, burning it with liquid oxygen to produce sulfur dioxide exhaust, referred to by some as a "Brimstone Rocket". Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon(as much as .27% in some mare soils), making it much easier to extract<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>. The expected specific impulse is around 285 seconds.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16524In-Situ Propellant Production2011-08-29T03:04:32Z<p>Silverwurm: /* Silane */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. The specific impulse of silane is slightly less than methane, and would use slightly less hydrogen for a given launch weight.<br />
<br />
Silane holds an advantage over methane as silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, burning it with liquid oxygen to produce sulfur dioxide exhaust, referred to by some as a "Brimstone Rocket". Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon(as much as .27% in some mare soils), making it much easier to extract<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>. The expected specific impulse is only 285 seconds, requiring a larger amount of fuel than a hydrogen rocket. However, the higher abundance of sulfur could outweigh this problem.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16523In-Situ Propellant Production2011-08-29T02:59:28Z<p>Silverwurm: /* Methane */</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) has also been proposed as a fuel for lunar use. Carbon is present in the lunar regolith in concentrations several times that of hydrogen, and heating the regolith to extract volatiles would result in some methane being produced, along with carbon monoxide and dioxide (which could be converted to methane by [[Lunar_Carbon_Production#Sabatier_Reaction|reacting with hydrogen]]). Burning methane with oxygen would give a specific impulse of around 300 seconds, requiring more fuel than a hydrogen-oxygen rocket. However, methane is only about 25% hydrogen by weight, and using methane as fuel results in about a 50% reduction in the amount of hydrogen needed for a given launch mass.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. This holds an advantage over both hydrogen and methane as silane contains even less hydrogen than methane (around 12% by weight), and silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, burning it with liquid oxygen to produce sulfur dioxide exhaust, referred to by some as a "Brimstone Rocket". Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon(as much as .27% in some mare soils), making it much easier to extract<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>. The expected specific impulse is only 285 seconds, requiring a larger amount of fuel than a hydrogen rocket. However, the higher abundance of sulfur could outweigh this problem.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=List_of_Propulsion_Systems&diff=16522List of Propulsion Systems2011-08-29T00:46:59Z<p>Silverwurm: /* Moon launched */ removed list, link to in situ propellant production sufficient</p>
<hr />
<div>{{Bootstrap}}<br />
<br />
==Moon launched==<br />
*Chemical Propellants<br>(see [[In Situ Propellant Production]])<br />
*[[Maglev]] launcher -- a la Gerard O'Neill and/or Heinlein<br />
*[[Ring launch]] or [[line launch]]<br />
<br />
==Earth launched==<br />
*[[Conventional Chemical]] -- (links to Astronautix might be useful here)<BR/><br />
*[[ATO, Airship To Orbit as per JP Aerospace]]<BR/><br />
*[[PDE, Pulse Detonation Engine]]<BR/><br />
*[[SCRAMJet]]<BR/><br />
*[[Space Elevator]]<BR/><br />
*[[Mass Driver]]<BR/><br />
*[[Rockoon 'Rockets launched from balloons']]<BR/><br />
*[[Tether]]<BR/><br />
*[[Inverted-aerobraking]]<BR/><br />
*[[Momentum from GTO]]<BR/><br />
<br />
==Interplanetary Transfer==<br />
*[[Conventional Chemical]] -- (links to Astronautix might be useful here)<br />
*[[Nuclear]] -- [[Orion]].<br />
*[[Magnetoplasma]]<br />
*[[Ion propulsion]]<br />
<br />
*[[Solar sail]]<br />
*[[Tether]]<br />
<br />
[[Category:Space Transport]]<br />
[[Category:Components]]<br />
[[Category:Hardware Plans]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=List_of_Propulsion_Systems&diff=16521List of Propulsion Systems2011-08-28T18:07:21Z<p>Silverwurm: reformatted list, added links</p>
<hr />
<div>{{Bootstrap}}<br />
<br />
==Moon launched==<br />
*Chemical Propellants (see also [[In Situ Propellant Production]])<br />
**[[In_Situ_Propellant_Production#Hydrogen|Hydrogen]]<br />
**[[In_Situ_Propellant_Production#Sulfur|Sulfur]]<br />
**[[In_Situ_Propellant_Production#Aluminum|Aluminum]]<br />
**[[In_Situ_Propellant_Production#Silicon|Silicon]]<br />
*[[Maglev]] launcher -- a la Gerard O'Neill and/or Heinlein<br />
*[[Ring launch]] or [[line launch]]<br />
<br />
<br />
==Earth launched==<br />
*[[Conventional Chemical]] -- (links to Astronautix might be useful here)<BR/><br />
*[[ATO, Airship To Orbit as per JP Aerospace]]<BR/><br />
*[[PDE, Pulse Detonation Engine]]<BR/><br />
*[[SCRAMJet]]<BR/><br />
*[[Space Elevator]]<BR/><br />
*[[Mass Driver]]<BR/><br />
*[[Rockoon 'Rockets launched from balloons']]<BR/><br />
*[[Tether]]<BR/><br />
*[[Inverted-aerobraking]]<BR/><br />
*[[Momentum from GTO]]<BR/><br />
<br />
==Interplanetary Transfer==<br />
*[[Conventional Chemical]] -- (links to Astronautix might be useful here)<br />
*[[Nuclear]] -- [[Orion]].<br />
*[[Magnetoplasma]]<br />
*[[Ion propulsion]]<br />
<br />
*[[Solar sail]]<br />
*[[Tether]]<br />
<br />
[[Category:Space Transport]]<br />
[[Category:Components]]<br />
[[Category:Hardware Plans]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=In-Situ_Propellant_Production&diff=16520In-Situ Propellant Production2011-08-28T18:06:53Z<p>Silverwurm: added methane and silane</p>
<hr />
<div>'''In-Situ Propellant Production''', or ''ISPP'', refers to manufacture of rocket fuel from local resources, a subset of [[In Situ Resource Utilization|In Situ Resource Utilization (''ISRU'')]]. Production of rocket fuel from lunar resources would be a great boost towards self sufficiency for any lunar colonization effort, eliminating the need for costly imports of a substance which would be needed in large quantities.<br />
<br />
[[Oxygen]] makes up nearly half the mass of the lunar crust, and is expected to be a major byproduct of industrial operations on the moon. As oxygen comprises much of the mass of currently used propellant systems (as much as 80%), its production alone would cut down the amount of propellant that would have to be imported by a large factor. Manufacture of the remaining fraction from lunar resources is hampered by the fact that most of the substances used in the manufacture of terrestrial propellants are rare or nonexistent in the lunar environment. Hence, this issue has produced a number of unconventional proposals.<br />
<br />
<br />
== Hydrogen ==<br />
<br />
[[Hydrogen]]-[[Oxygen]] rockets have two main advantages in a lunar environment. First, the specific impulse (essentially the amount of thrust gained per unit of fuel burned) is listed as 450 seconds, the highest of any chemical rocket ever flown, meaning less fuel mass is needed compared to other fuel types. Second, hydrogen-oxygen rockets have been used since the first days of spaceflight, and as such the technology is well developed.<br />
<br />
The biggest disadvantage of this approach is the scarcity of hydrogen from lunar sources. Hydrogen is present at the poles in the form of water ice, as well as being available in the regolith in low concentrations (see [[Volatiles]]). The mining of water ice in the polar regions is complicated by very cold (100 K and below) temperatures. There is also concern about the depletion of these resources, as the exact amount available is not known. Extraction from the lunar regolith is an extremely energy intensive process, requiring the processing of massive quantities of lunar material at high temperatures. There is a great deal of doubt that these processes can supply the needs of lunar colonization. <br />
<br />
One way to address the great expense of extracting hydrogen from the lunar surface is to recycle the rocket exhaust of a [[rocket-sled to orbit]].<br />
<br />
== Methane ==<br />
Lunar [[carbon]] can be extracted from the regolith by heating (as with hydrogen). Some of the carbon would volatilize out as methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>) directly, and the remainder could be [[Lunar_Carbon_Production#Sabatier_Reaction|reacted with hydrogen to produce additional methane]], which could be used as fuel. Since carbon is several times more abundant than hydrogen in the lunar soil, and since methane is approximately 75% carbon by weight, methane is significantly more abundant in lunar regolith than pure hydrogen. The abundance of carbon is still quite low however, and significant extraction would be necessary to supply the needs of a lunar colony.<br />
<br />
== Silane ==<br />
Another alternative is to combine lunar obtained hydrogen with silicon to create silane ([[Silicon|Si]][[Hydrogen|H]]<sub>4</sub>), which when burned with oxygen would produce water and silica as exhaust. This holds an advantage over both hydrogen and methane as silane contains even less hydrogen than methane (around 12% by weight), and silicon is vastly more plentiful than carbon (nearly 25% of the moons crust). In addition, technology for using silane as propellant is currently utilized in supersonic ramjets, where it is used as a starting propellant since it ignites spontaneously in air. As such, technology for handling and injecting silane into a combustion chamber is already developed.<br />
<br />
One disadvantage of this approach is the complexity of producing silane. The process used terrestrially for silane production is long, rather complex, and requires a number of reagents that are quite rare on the moon. Methane and hydrogen production are quite straightforward by comparison.<br />
<br />
== Sulfur ==<br />
<br />
Another proposed solution is to use [[sulfur]] as a propellant, burning it with liquid oxygen to produce sulfur dioxide exhaust, referred to by some as a "Brimstone Rocket". Sulfur is present in the lunar regolith in much higher quantities than both hydrogen and carbon(as much as .27% in some mare soils), making it much easier to extract<ref>[http://library.lanl.gov/cgi-bin/getfile?00261154.pdf V. T. Vaniman, D. R. Pettit, G. Heiken. "Uses of Lunar Sulfur" Los Alamos National Laboratory, 1988]</ref>. The expected specific impulse is only 285 seconds, requiring a larger amount of fuel than a hydrogen rocket. However, the higher abundance of sulfur could outweigh this problem.<br />
<br />
== Aluminum ==<br />
<br />
Is is proposed that [[aluminum]] could be used as a fuel. This would have the advantage of virtual inexhaustability, as aluminum makes up a significant percentage of the moons crust. One downside is aluminum's high melting point(compared to other propellants), which would make conventional bi-propellant fuel processes difficult.<br />
<br />
One proposed solution to this problem is to mix finely powdered aluminum with liquid oxygen, adding a small amount of fumed silica to the mix. The result would be a gelled monopropellant which would provide an estimated specific impulse of 285 seconds<ref>[http://www.asi.org/adb/06/09/03/02/095/al-o-propellants.html Larry Jay Friesen. "LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT". Moon Miners Manifesto #95, May 1996]</ref>, the same as with sulfur. This approach has been tested on a small scale, and was determined to be reasonably stable<ref>[http://www.wickmanspacecraft.com/moon1.html John Wickman. "Using Lunar Soil For Propellants & Concrete". Wickman Spacecraft & Propulsion Company]</ref>.<br />
<br />
One potential issue with this approach is the production of dust. As the exhaust cools, particles of aluminum oxide would form, which could be an issue for heavy use. Proper design of the engine could mitigate this however. If the combustion was complete and all products were entirely vaporized upon ejection, the resulting dust should be quite small, perhaps microscopic in size, and traveling at sufficient speed to allow for wide dispersal. Current spacecraft are already designed to handle dust of this size, and its generation should not endanger their use.<br />
<br />
== Silicon ==<br />
<br />
Lunar [[silicon]] could possibly be used in the same manner as [[aluminum]], as they are similar in both atomic weight and potential energy, and hence could have similar specific impulses. Silicon has been utilized in test mixtures, powdered and mixed in a liquid oxygen gel as with aluminum<ref>[http://ae-www.technion.ac.il/~rocketw3/benny5.pdf Benveniste Natan and Shai Rahimi. "THE STATUS OF GEL PROPELLANTS IN YEAR 2000". Technion - Israel Institute of Technology, Faculty of Aerospace Engineering. Table 6]</ref>. As silicon dioxide is the most common component of the lunar crust (nearly half by weight), it's use in this manner is attractive.<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
[[Category:ISRU]]<br />
[[Category:Chemistry]]<br />
[[Category:Boosters]]</div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Carbon_Production&diff=16519Lunar Carbon Production2011-08-28T17:33:39Z<p>Silverwurm: /* Sabatier Reaction */</p>
<hr />
<div>== Introduction ==<br />
Lunar [[carbon]] is found in trace amounts in the lunar regolith, where it can be extracted by heating (see [[Volatiles]]). This process results in a number of carbon compounds, chiefly carbon monoxide ([[Carbon|C]][[Oxygen|O]]), carbon dioxide ([[Carbon|C]][[Oxygen|O]]<sub>2</sub>), and methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>). It is desirable to produce elemental carbon from these feedstocks for production of lunar steel, as well as various other uses. In addition, processes to reduce these substances would be necessary in order to recycle carbon consumed in various industrial processes. A number of methods have been proposed for this.<br />
<br />
== Carbon Monoxide Reduction ==<br />
Carbon monoxide can be subjected to temperatures of around 700°C to produce carbon and carbon dioxide, a reaction that occurs in sooty chimneys.<ref>[http://www.moonminer.com/Basic-Chemistry-for-Moon-Miners.html Dietzler,Dave. "Basic Chemistry for Moon Miners" www.moonminer.com]</ref>:<br />
<br />
2 [[Carbon Monoxide|CO]] ==> [[Carbon|C]] + [[Carbon Dioxide|CO<sub>2</sub>]]<br />
<br />
This would recover half the carbon present in the gas. Further reduction of the carbon dioxide would be required to obtain the rest.<br />
<br />
== Methane Reduction ==<br />
Methane may be useful on its own as a feedstock for producing various hydrocarbons. If elemental carbon is desired, it can be subjected to thermal decomposition at high temperatures, producing [[hydrogen]] as a byproduct:<br />
<br>[[Methane|CH<sub>4</sub>]] ==> [[Carbon|C]] + 2 [[Hydrogen|H]]<sub>2</sub><br />
<br />
Production of carbon and hydrogen in this manner has been tested with various catalysts. All had issues with carbon deposition fouling the catalyst surface. Uncatalyzed production seems to require temperatures significantly greater than 900°C <ref>Zabidi, N.A.M. and Zein, S.H.S. and Mohamed, A.R. [http://www.utp.edu.my/publications/platform/Platform%20v3n2.pdf#page=4 "Hydrogen production by catalytic decomposition of methane"] Technology Platform: Oilfield Gas Treatment and Utilization</ref>.<br />
<br />
Uncatalyzed production has the advantage that any vessel capable of holding and heating the methane could be used as a reactor, even a simple pipe<ref>http://en.wikipedia.org/wiki/Sabatier_reaction#International_Space_Station_life_support</ref>, which could be periodically subjected to an auger to remove deposited carbon.<br />
<br />
== Carbon Dioxide Reduction ==<br />
<br />
=== Bosch Reaction ===<br />
<br />
In the Bosch Reaction, carbon dioxide is reacted with hydrogen in the presence of an iron catalyst at temperatures between 530º and 730º C, producing carbon and water in a slightly exothermic process. The water is [[Water Splitting|split]], recovering the hydrogen and producing oxygen.<br />
<br />
<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 2 [[Hydrogen|H]]<sub>2</sub> ==> [[Carbon|C]] + 2 [[Water|H<sub>2</sub>O]] (Bosch Reaction)<br />
<br>2 [[Water|H<sub>2</sub>O]] ==> [[Oxygen|O]]<sub>2</sub> + 2 [[Hydrogen|H]]<sub>2</sub> ([[Water Splitting]])<br />
<br>Net Reaction: [[Carbon Dioxide|CO<sub>2</sub>]] ==> [[Carbon|C]] + [[Oxygen|O]]<sub>2</sub><br />
<br />
<br />
This possesses the same disadvantage as low temperature methane decomposition, namely that the produced carbon builds up on the catalyst surface, reducing the efficiency. A combination of continuous mechanical scraping and large catalyst surfaces could make the reaction useable.<br />
<br />
The bosch reaction is a subject of current research for space based carbon dioxide reduction<ref>http://people.oregonstate.edu/~atwaterj/h2o_gen.htm</ref>.<br />
<br />
=== Sabatier Reaction ===<br />
Another way to produce carbon from carbon dioxide is by use of the Sabatier reaction, which again involves reacting carbon dioxide with hydrogen, this time in the presence of a nickel catalyst. This process produces water and methane as reaction products:<br />
<br />
<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 4 [[Hydrogen|H]]<sub>2</sub> ==> [[Methane|CH<sub>4</sub>]] + 2 [[Water|H<sub>2</sub>O]]<br />
<br />
The water is split to recover hydrogen and oxygen, as in application of the Bosch reaction. The methane could be decomposed to carbon and hydrogen (see [[Lunar_Carbon_Production#Methane_Reduction|previous section]]), or used for the production of other hydrocarbons.<br />
<br />
The Sabatier Reaction is currently utilized on board the International Space Station, except that the methane produced is dumped overboard.<br />
<br />
=== Direct CO2 Electrolysis ===<br />
Another option is to directly electrolyze carbon dioxide<ref>[http://rtreport.ksc.nasa.gov/techreports/2002report/600%20Fluid%20Systems/609.html "Space Habitat Carbon Dioxide Electrolysis to Oxygen". Fluid System Technologies, 2002]</ref>, resulting in oxygen and carbon monoxide.<br />
<br><br />
2 [[Carbon Dioxide|CO<sub>2</sub>]] ==> 2 [[Carbon Monoxide|CO]] + [[Oxygen|O]]<sub>2</sub><br />
<br />
An appropriate membrane could be utilized to separate the oxygen. The carbon monoxide could be reduced to carbon and carbon dioxide (see [[Lunar Carbon Production#Carbon Monoxide Reduction|previous section]]), returning the carbon dioxide to the cell for further reduction.<br />
<br />
A number of processes utilizing carbon monoxide as a reducing agent have been proposed for lunar use. These processes would consume carbon monoxide and produce carbon dioxide. A direct electrolysis system could be used in this case on the produced carbon dioxide, with the carbon monoxide recirculated back into the system rather than reduced further.<br />
<br />
=== Biological Reduction ===<br />
Carbon could be produced by heating organic material in the absence of oxygen to produce charcoal. This would require some method of removing the ash which would inevitably be present.<br />
<br />
Growing plants specifically to produce carbon in this fashion would probably be more energy intensive than other methods. However, processing of organic waste products into carbon presents an attractive recycling mechanism, as it can be utilized on the non-edible parts of food plants and even human feces. This process would most likely be carried out in conjunction with other carbon production methods, as the human population would need to be quite high for it to supply all the carbon.<br />
<br />
== References ==<br />
<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Carbon_Production&diff=16518Lunar Carbon Production2011-08-28T17:33:06Z<p>Silverwurm: /* Sabatier Reaction */</p>
<hr />
<div>== Introduction ==<br />
Lunar [[carbon]] is found in trace amounts in the lunar regolith, where it can be extracted by heating (see [[Volatiles]]). This process results in a number of carbon compounds, chiefly carbon monoxide ([[Carbon|C]][[Oxygen|O]]), carbon dioxide ([[Carbon|C]][[Oxygen|O]]<sub>2</sub>), and methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>). It is desirable to produce elemental carbon from these feedstocks for production of lunar steel, as well as various other uses. In addition, processes to reduce these substances would be necessary in order to recycle carbon consumed in various industrial processes. A number of methods have been proposed for this.<br />
<br />
== Carbon Monoxide Reduction ==<br />
Carbon monoxide can be subjected to temperatures of around 700°C to produce carbon and carbon dioxide, a reaction that occurs in sooty chimneys.<ref>[http://www.moonminer.com/Basic-Chemistry-for-Moon-Miners.html Dietzler,Dave. "Basic Chemistry for Moon Miners" www.moonminer.com]</ref>:<br />
<br />
2 [[Carbon Monoxide|CO]] ==> [[Carbon|C]] + [[Carbon Dioxide|CO<sub>2</sub>]]<br />
<br />
This would recover half the carbon present in the gas. Further reduction of the carbon dioxide would be required to obtain the rest.<br />
<br />
== Methane Reduction ==<br />
Methane may be useful on its own as a feedstock for producing various hydrocarbons. If elemental carbon is desired, it can be subjected to thermal decomposition at high temperatures, producing [[hydrogen]] as a byproduct:<br />
<br>[[Methane|CH<sub>4</sub>]] ==> [[Carbon|C]] + 2 [[Hydrogen|H]]<sub>2</sub><br />
<br />
Production of carbon and hydrogen in this manner has been tested with various catalysts. All had issues with carbon deposition fouling the catalyst surface. Uncatalyzed production seems to require temperatures significantly greater than 900°C <ref>Zabidi, N.A.M. and Zein, S.H.S. and Mohamed, A.R. [http://www.utp.edu.my/publications/platform/Platform%20v3n2.pdf#page=4 "Hydrogen production by catalytic decomposition of methane"] Technology Platform: Oilfield Gas Treatment and Utilization</ref>.<br />
<br />
Uncatalyzed production has the advantage that any vessel capable of holding and heating the methane could be used as a reactor, even a simple pipe<ref>http://en.wikipedia.org/wiki/Sabatier_reaction#International_Space_Station_life_support</ref>, which could be periodically subjected to an auger to remove deposited carbon.<br />
<br />
== Carbon Dioxide Reduction ==<br />
<br />
=== Bosch Reaction ===<br />
<br />
In the Bosch Reaction, carbon dioxide is reacted with hydrogen in the presence of an iron catalyst at temperatures between 530º and 730º C, producing carbon and water in a slightly exothermic process. The water is [[Water Splitting|split]], recovering the hydrogen and producing oxygen.<br />
<br />
<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 2 [[Hydrogen|H]]<sub>2</sub> ==> [[Carbon|C]] + 2 [[Water|H<sub>2</sub>O]] (Bosch Reaction)<br />
<br>2 [[Water|H<sub>2</sub>O]] ==> [[Oxygen|O]]<sub>2</sub> + 2 [[Hydrogen|H]]<sub>2</sub> ([[Water Splitting]])<br />
<br>Net Reaction: [[Carbon Dioxide|CO<sub>2</sub>]] ==> [[Carbon|C]] + [[Oxygen|O]]<sub>2</sub><br />
<br />
<br />
This possesses the same disadvantage as low temperature methane decomposition, namely that the produced carbon builds up on the catalyst surface, reducing the efficiency. A combination of continuous mechanical scraping and large catalyst surfaces could make the reaction useable.<br />
<br />
The bosch reaction is a subject of current research for space based carbon dioxide reduction<ref>http://people.oregonstate.edu/~atwaterj/h2o_gen.htm</ref>.<br />
<br />
=== Sabatier Reaction ===<br />
Another way to produce carbon from carbon dioxide is by use of the Sabatier reaction, which again involves reacting carbon dioxide with hydrogen, this time in the presence of a nickel catalyst. This process produces water and methane as reaction products:<br />
<br />
<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 4 [[Hydrogen|H]]<sub>2</sub> ==> [[Methane|CH<sub>4</sub>]] + 2 [[Water|H<sub>2</sub>O]]<br />
<br />
The water is split to recover hydrogen and oxygen, as in application of the Bosch reaction.<br />
<br />
The methane could be decomposed to carbon and hydrogen (see [[Lunar_Carbon_Production#Methane_Reduction|previous section]]), used for the production of other hydrocarbons.<br />
<br />
The Sabatier Reaction is currently utilized on board the International Space Station, except that the methane produced is dumped overboard.<br />
<br />
=== Direct CO2 Electrolysis ===<br />
Another option is to directly electrolyze carbon dioxide<ref>[http://rtreport.ksc.nasa.gov/techreports/2002report/600%20Fluid%20Systems/609.html "Space Habitat Carbon Dioxide Electrolysis to Oxygen". Fluid System Technologies, 2002]</ref>, resulting in oxygen and carbon monoxide.<br />
<br><br />
2 [[Carbon Dioxide|CO<sub>2</sub>]] ==> 2 [[Carbon Monoxide|CO]] + [[Oxygen|O]]<sub>2</sub><br />
<br />
An appropriate membrane could be utilized to separate the oxygen. The carbon monoxide could be reduced to carbon and carbon dioxide (see [[Lunar Carbon Production#Carbon Monoxide Reduction|previous section]]), returning the carbon dioxide to the cell for further reduction.<br />
<br />
A number of processes utilizing carbon monoxide as a reducing agent have been proposed for lunar use. These processes would consume carbon monoxide and produce carbon dioxide. A direct electrolysis system could be used in this case on the produced carbon dioxide, with the carbon monoxide recirculated back into the system rather than reduced further.<br />
<br />
=== Biological Reduction ===<br />
Carbon could be produced by heating organic material in the absence of oxygen to produce charcoal. This would require some method of removing the ash which would inevitably be present.<br />
<br />
Growing plants specifically to produce carbon in this fashion would probably be more energy intensive than other methods. However, processing of organic waste products into carbon presents an attractive recycling mechanism, as it can be utilized on the non-edible parts of food plants and even human feces. This process would most likely be carried out in conjunction with other carbon production methods, as the human population would need to be quite high for it to supply all the carbon.<br />
<br />
== References ==<br />
<br />
<references/></div>Silverwurmhttps://lunarpedia.org/index.php?title=Chromium&diff=16508Chromium2011-08-24T07:18:07Z<p>Silverwurm: changed external link to inline reference</p>
<hr />
<div>{{Element |<br />
name=Chromium |<br />
symbol=Cr |<br />
available=abundant |<br />
need=useful |<br />
number=24 |<br />
mass=51.9961 |<br />
group=6 |<br />
period=4 |<br />
phase=Solid |<br />
series=Transition Metals |<br />
density=7.15 g/cm3 |<br />
melts=2180K,<BR/>1907°C,<BR/>3465°F |<br />
boils=2944K,<BR/>2671°C,<BR/>4840°F |<br />
isotopes=50<BR/>52<BR/>53<BR/>54 |<br />
prior=[[Vanadium|<FONT color="#7F7FFF">V</FONT>]] |<br />
next=[[Manganese|<FONT color="#7F7FFF">Mn</FONT>]] |<br />
above=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
aprior=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
anext=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
below=[[Molybdenum|<FONT color="#7F7FFF">Mo</FONT>]] |<br />
bprior=[[Niobium|<FONT color="#7F7FFF">Nb</FONT>]] |<br />
bnext=[[Technetium|<FONT color="#7F7FFF">Tc</FONT>]] |<br />
radius=140 |<br />
bohr=166 |<br />
covalent=127 |<br />
vdwr= |<br />
irad=(+3) 62 |<br />
ipot=6.77 |<br />
econfig=1s<sup>2</sup> <br/>2s<sup>2</sup> 2p<sup>6</sup> <br/>3s<sup>2</sup> 3p<sup>6</sup> 3d<sup>5</sup> <br/>4s<sup>1</sup> |<br />
eshell=2, 8, 13, 1 |<br />
enega=1.66 |<br />
eaffin=0.67 |<br />
oxstat=6, '''3''', 2 |<br />
magn=Antiferromagnetic<BR/>w/Spin Density Wave |<br />
cryst=Body centered cubic |<br />
}}<br />
'''Chromium''' is a Transition Metal in group 6.<br />
It has a Body centered cubic crystalline structure.<br />
This element has 4 stable isotopes: 50, 52, 53, and 54. <br />
<BR/><BR/><br />
"Chromium use in iron, steel, and nonferrous alloys enhances hardenability and resistance to corrosion and oxidation. The use of chromium to produce stainless steel and nonferrous alloys are two of its more important applications. Other applications are in alloy steel, plating of metals, pigments, leather processing, catalysts, surface treatments, and refractories." - USGS Chromium Statistics and Information<ref>http://minerals.usgs.gov/minerals/pubs/commodity/chromium/</ref><br />
<BR/><BR/><br />
<br />
Chromium on Luna would find many uses, not least of which is the creation of corrosion resistant alloys for industrial processes. Due to its high melting point, chromium is also a useful component in the construction of electric resistance heating elements<ref>http://www.moonminer.com/Speculation-Lunar_Chromium.html</ref>. Addition of chromium also increases the strength of various alloys.<br />
<br />
The most important and abundant ore of chromium is [[chromite]]. Geologic surveys of the moon have located large deposits of chromite on the Sinus Aestuum, covering an area thousands of square kilometers in size<ref>http://www.nasa.gov/topics/moonmars/features/moonrock-king_prt.htm</ref>. It is believed that these deposits are located all across the moon, but are buried in deeper layers, and that the deposits on the Sinus Aestuum are the result of a meteorite impact blasting away the overburden.<br />
<br />
[[Chromite]] could be reduced to an [[Iron]]-Chromium alloy using the [[FFC Cambridge Process]], which could then be refined to pure Chromium, or could could be used directly for production of stainless steel or other iron alloys.<br />
<BR/><BR/><br />
<br />
<br />
== References ==<br />
<references/><br />
<br />
<br />
<br />
<br />
[[Category:Antiferromagnetic Elements]]<br />
[[Category:Solids]]<br />
[[Category:Transition Metals ]]<br />
<br />
<!-- Generated by a gamma candidate version of Autostub2 (Test 9) --></div>Silverwurmhttps://lunarpedia.org/index.php?title=Chromium&diff=16496Chromium2011-08-22T02:08:21Z<p>Silverwurm: changed inline links to references</p>
<hr />
<div>{{Element |<br />
name=Chromium |<br />
symbol=Cr |<br />
available=abundant |<br />
need=useful |<br />
number=24 |<br />
mass=51.9961 |<br />
group=6 |<br />
period=4 |<br />
phase=Solid |<br />
series=Transition Metals |<br />
density=7.15 g/cm3 |<br />
melts=2180K,<BR/>1907°C,<BR/>3465°F |<br />
boils=2944K,<BR/>2671°C,<BR/>4840°F |<br />
isotopes=50<BR/>52<BR/>53<BR/>54 |<br />
prior=[[Vanadium|<FONT color="#7F7FFF">V</FONT>]] |<br />
next=[[Manganese|<FONT color="#7F7FFF">Mn</FONT>]] |<br />
above=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
aprior=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
anext=<SMALL><FONT color="#7F7F7F">N/A</FONT></SMALL> |<br />
below=[[Molybdenum|<FONT color="#7F7FFF">Mo</FONT>]] |<br />
bprior=[[Niobium|<FONT color="#7F7FFF">Nb</FONT>]] |<br />
bnext=[[Technetium|<FONT color="#7F7FFF">Tc</FONT>]] |<br />
radius=140 |<br />
bohr=166 |<br />
covalent=127 |<br />
vdwr= |<br />
irad=(+3) 62 |<br />
ipot=6.77 |<br />
econfig=1s<sup>2</sup> <br/>2s<sup>2</sup> 2p<sup>6</sup> <br/>3s<sup>2</sup> 3p<sup>6</sup> 3d<sup>5</sup> <br/>4s<sup>1</sup> |<br />
eshell=2, 8, 13, 1 |<br />
enega=1.66 |<br />
eaffin=0.67 |<br />
oxstat=6, '''3''', 2 |<br />
magn=Antiferromagnetic<BR/>w/Spin Density Wave |<br />
cryst=Body centered cubic |<br />
}}<br />
'''Chromium''' is a Transition Metal in group 6.<br />
It has a Body centered cubic crystalline structure.<br />
This element has 4 stable isotopes: 50, 52, 53, and 54. <br />
<BR/><BR/><br />
"Chromium use in iron, steel, and nonferrous alloys enhances hardenability and resistance to corrosion and oxidation. The use of chromium to produce stainless steel and nonferrous alloys are two of its more important applications. Other applications are in alloy steel, plating of metals, pigments, leather processing, catalysts, surface treatments, and refractories." - USGS Chromium Statistics and Information<ref>http://minerals.usgs.gov/minerals/pubs/commodity/chromium/</ref><br />
<BR/><BR/><br />
<br />
Chromium on Luna would find many uses, not least of which is the creation of corrosion resistant alloys for industrial processes. Due to its high melting point, chromium is also a useful component in the construction of electric resistance heating elements. Addition of chromium also increases the strength of various alloys.<br />
<br />
The most important and abundant ore of chromium is [[chromite]]. Geologic surveys of the moon have located large deposits of chromite on the Sinus Aestuum, covering an area thousands of square kilometers in size<ref>http://www.nasa.gov/topics/moonmars/features/moonrock-king_prt.htm</ref>. It is believed that these deposits are located all across the moon, but are buried in deeper layers, and that the deposits on the Sinus Aestuum are the result of a meteorite impact blasting away the overburden.<br />
<br />
[[Chromite]] could be reduced to an [[Iron]]-Chromium alloy using the [[FFC Cambridge Process]], which could then be refined to pure Chromium, or could could be used directly for production of stainless steel or other iron alloys.<br />
<BR/><BR/><br />
<br />
<br />
== References ==<br />
<references/><br />
<br />
== External Links ==<br />
[http://www.moonminer.com/Speculation-Lunar_Chromium.html Lunar Chromium Uses]<br />
<br />
<br />
<br />
<br />
[[Category:Antiferromagnetic Elements]]<br />
[[Category:Solids]]<br />
[[Category:Transition Metals ]]<br />
<br />
<!-- Generated by a gamma candidate version of Autostub2 (Test 9) --></div>Silverwurmhttps://lunarpedia.org/index.php?title=Lunar_Carbon_Production&diff=16493Lunar Carbon Production2011-08-21T02:05:51Z<p>Silverwurm: /* Direct CO2 Electrolysis */ added link</p>
<hr />
<div>== Introduction ==<br />
Lunar [[carbon]] is found in trace amounts in the lunar regolith, where it can be extracted by heating (see [[Volatiles]]). This process results in a number of carbon compounds, chiefly carbon monoxide ([[Carbon|C]][[Oxygen|O]]), carbon dioxide ([[Carbon|C]][[Oxygen|O]]<sub>2</sub>), and methane ([[Carbon|C]][[Hydrogen|H]]<sub>4</sub>). It is desirable to produce elemental carbon from these feedstocks for production of lunar steel, as well as various other uses. In addition, processes to reduce these substances would be necessary in order to recycle carbon consumed in various industrial processes. A number of methods have been proposed for this.<br />
<br />
== Carbon Monoxide Reduction ==<br />
Carbon monoxide can be subjected to temperatures of around 700°C to produce carbon and carbon dioxide, a reaction that occurs in sooty chimneys.<ref>http://www.moonminer.com/Basic-Chemistry-for-Moon-Miners.html</ref>:<br />
<br />
2 [[Carbon Monoxide|CO]] ==> [[Carbon|C]] + [[Carbon Dioxide|CO<sub>2</sub>]]<br />
<br />
This would recover half the carbon present in the gas. Further reduction of the carbon dioxide would be required to obtain the rest.<br />
<br />
== Methane Reduction ==<br />
Methane may be useful on its own as a feedstock for producing various hydrocarbons. If elemental carbon is desired, it can be subjected to thermal decomposition at high temperatures, producing [[hydrogen]] as a byproduct:<br />
<br>[[Methane|CH<sub>4</sub>]] ==> [[Carbon|C]] + 2 [[Hydrogen|H]]<sub>2</sub><br />
<br />
Production of carbon and hydrogen in this manner has been tested with various catalysts. All had issues with carbon deposition fouling the catalyst surface. Uncatalyzed production seems to require temperatures significantly greater than 900°C <ref>Zabidi, N.A.M. and Zein, S.H.S. and Mohamed, A.R. [http://www.utp.edu.my/publications/platform/Platform%20v3n2.pdf#page=4 "Hydrogen production by catalytic decomposition of methane"] Technology Platform: Oilfield Gas Treatment and Utilization</ref>.<br />
<br />
Uncatalyzed production has the advantage that any vessel capable of holding and heating the methane could be used as a reactor, even a simple pipe<ref>http://en.wikipedia.org/wiki/Sabatier_reaction#International_Space_Station_life_support</ref>, which could be periodically subjected to an auger to remove deposited carbon.<br />
<br />
== Carbon Dioxide Reduction ==<br />
<br />
=== Bosch Reaction ===<br />
<br />
In the Bosch Reaction, carbon dioxide is reacted with hydrogen in the presence of an iron catalyst at temperatures between 530º and 730º C, producing carbon and water in a slightly exothermic process. The water is [[Water Splitting|split]], recovering the hydrogen and producing oxygen.<br />
<br />
<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 2 [[Hydrogen|H]]<sub>2</sub> ==> [[Carbon|C]] + 2 [[Water|H<sub>2</sub>O]] (Bosch Reaction)<br />
<br>2 [[Water|H<sub>2</sub>O]] ==> [[Oxygen|O]]<sub>2</sub> + 2 [[Hydrogen|H]]<sub>2</sub> ([[Water Splitting]])<br />
<br>Net Reaction: [[Carbon Dioxide|CO<sub>2</sub>]] ==> [[Carbon|C]] + [[Oxygen|O]]<sub>2</sub><br />
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This possesses the same disadvantage as low temperature methane decomposition, namely that the produced carbon builds up on the catalyst surface, reducing the efficiency. A combination of continuous mechanical scraping and large catalyst surfaces could make the reaction useable.<br />
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The bosch reaction is a subject of current research for space based carbon dioxide reduction<ref>http://people.oregonstate.edu/~atwaterj/h2o_gen.htm</ref>.<br />
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=== Sabatier Reaction ===<br />
Another way to produce carbon from carbon dioxide is by use of the Sabatier reaction, which again involves reacting carbon dioxide with hydrogen, this time in the presence of a nickel catalyst. This process produces water and methane as reaction products:<br />
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<br>[[Carbon Dioxide|CO<sub>2</sub>]] + 4 [[Hydrogen|H]]<sub>2</sub> ==> [[Methane|CH<sub>4</sub>]] + 2 [[Water|H<sub>2</sub>O]]<br />
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The water is split to recover hydrogen and oxygen, as in application of the Bosch reaction, and the methane is decomposed to carbon and hydrogen (see [[Lunar_Carbon_Production#Methane_Reduction|previous section]]).<br />
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The Sabatier Reaction is currently utilized on board the International Space Station, except that the methane produced is dumped overboard.<br />
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=== Direct CO2 Electrolysis ===<br />
Another option is to directly electrolyze carbon dioxide<ref>http://rtreport.ksc.nasa.gov/techreports/2002report/600%20Fluid%20Systems/609.html</ref>, resulting in oxygen and carbon monoxide.<br />
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2 [[Carbon Dioxide|CO<sub>2</sub>]] ==> 2 [[Carbon Monoxide|CO]] + [[Oxygen|O]]<sub>2</sub><br />
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An appropriate membrane could be utilized to separate the oxygen. The carbon monoxide could be reduced to carbon and carbon dioxide (see [[Lunar Carbon Production#Carbon Monoxide Reduction|previous section]]), returning the carbon dioxide to the cell for further reduction.<br />
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A number of processes utilizing carbon monoxide as a reducing agent have been proposed for lunar use. These processes would consume carbon monoxide and produce carbon dioxide. A direct electrolysis system could be used in this case on the produced carbon dioxide, with the carbon monoxide recirculated back into the system rather than reduced further.<br />
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=== Biological Reduction ===<br />
Carbon could be produced by heating organic material in the absence of oxygen to produce charcoal. This would require some method of removing the ash which would inevitably be present.<br />
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Growing plants specifically to produce carbon in this fashion would probably be more energy intensive than other methods. However, processing of organic waste products into carbon presents an attractive recycling mechanism, as it can be utilized on the non-edible parts of food plants and even human feces. This process would most likely be carried out in conjunction with other carbon production methods, as the human population would need to be quite high for it to supply all the carbon.<br />
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== References ==<br />
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<references/></div>Silverwurm