Talk:Team FREDNET

Requests for information

Hello, I am a volunteer of Team FREDNET coordinating communications with Lunarpedia. We regularly need information about the space and lunar environment to support development of our lunar mission, and would be very appreciative if Lunarpedia contributors are able to help us out. I'm adding requests for such information in the list below, in order of importance (most important at top). Not all requests for information are 'mission critical', but in any event it will help draw as complete a picture of the mission environment as possible.--Anders Feder 13:56, 3 January 2009 (UTC)

Open requests

• Radiation environment throughout mission. We need a thorough characterization of the radiation environment throughout a mission from the Earth to the Moon, including on Earth, in transit and on the Moon. It must be detailed enough to allow our engineers to design appropriate radiation shielding from the information. --Anders Feder 14:21, 3 January 2009 (UTC)

If you are interested in how to build space hardware for space environments, a good place to start is this book:

Space Mission Analysis and Design (Third Edition) (Softback) [James R. Wertz and Wiley J. Larson, eds. - 1999]; 969 pages, 1999, Microcosm/Kluwer; ISBN 978-1881883104 [1];

Then this:

Guide to Modeling Earth's Trapped Radiation Environment (Softback) [AIAA - 1999] 55 pgs, 1999, AIAA

ISBN 1-56347-349-6

Then this:

Introduction to the Space Environment (Second Edition) (Softback) [Thomas F. Tascione - 1994] 0445S

Thomas F. Tascione

151 pgs, 1994, Krieger Publishing

ISBN 978-0894640445

- Preceeding unsigned comment by Charles F. Radley

Thanks for the recommendations. I've reposted them here. --Anders Feder 20:37, 7 January 2009 (UTC)

• Calculating incident infrared radiation on lunar surface. This is more of a general physics problem than specifically a lunar science problem: how do you calculate the amount of infrared radiation emitted by the lunar surface that is incident on an area at the surface, such as the sides of our lunar lander? For a full description of the problem and an illustration, please see this page. --Anders Feder 19:19, 11 January 2009 (UTC)

Spoke to a friend and this is what I got, in all its mathematical terminology: "Basically, you need to figure out the solid angle A(x, y) subtended by the lander from any point (x, y) on the Moon’s surface. That’s a straightforward but messy bit of trig. The amount of radiation captured from the area element [(x, y), (x+dx, y+dy)] will then be A(x, y)/2pi dx dy times the radiation emitted per unit area, which you can calculate from the info in the problem. (It’s A/2pi because the solid angle of a hemisphere is 2pi steradians.) Finally, you integrate that over all (x, y)." - Jarogers2001 23:21, 11 January 2009 (UTC)

Excellent, James. Reposted here. Thanks. --Anders Feder 00:53, 12 January 2009 (UTC)

Marcel has a follow-up question: "In your calculation you say that radiation goes out evenly spread out over all possible directions in a hemisphere. Is that physically correct? Isn't it possible that we have another repartition ?" (see sketch here)

The left case is correct. If you model a very small piece of the surface then direction is irrelevant because energy is emitted in a uniform sphere. For an arbitrarily large number of pieces arranged as a surface, energy "rays" which point towards or are emitted into the surface are absorbed. - Jarogers2001 04:10, 14 January 2009 (UTC)

--Anders Feder 21:49, 12 January 2009 (UTC)

• Regolith composition at Apollo landing sites. The composition of regolith varies greatly with location on the Moon. We need to know the composition of the surface material at our landing site to calculate its frictional properties, which in turn will be used to design our rover. We have not selected a landing site yet, but it will most likely be one of the heritage Apollo landing sites. Hence, we need to know the exact geological composition of the lunar regolith at these sites. Since surface samples were taken by the Apollo astronauts, this information should be available from NASA in some form.--Anders Feder 13:56, 3 January 2009 (UTC)

Apollo Sample Catalogs

The Effects of Lunar Dust on EVA Systems During the Apollo Missions

The Apollo Experience Lessons Learned for Constellation Lunar Dust Management

Lunar Sample Studies

JSC-1 - Approximately 27,000 lb of JSC-1 simulant is currently available for distribution to qualified investigators. The only cost is for shipping. The material is stored at the Texas A&M Lunar Soil Simulant Laboratory. Investigators desiring a portion of this simulant should address their requests to Dr. Walter Boles, Department of Civil Engineering, Texas A&M University, College Station, TX 77843 (Telephone 409-845-2493, fax 409-862-2800).

Lunar Dust

Thanks for the links - they have been integrated here and here and here. --Anders Feder 15:44, 4 January 2009 (UTC)

• Illuminance on the lunar surface. We are trying to figure out how (particularly, how brightly) objects on the lunar surface (not the lunar surface itself) are illuminated at various times of lunar day and night. We need this information to design visual systems (cameras) for our lander and rover. At least three sources of illuminance has to be taken into consideration: sunshine (light from the Sun), earthshine (sunlight reflected by Earth), and moonshine (sunlight reflected by the lunar surface itself). --Anders Feder 14:14, 3 January 2009 (UTC)

I'm at a loss on this one. Charles, is this covered in the books you listed? - Jarogers2001 10:32, 7 January 2009 (UTC)

Closed requests

• Designers of Apollo RTGs. We have been considering using the SNAP-27 RTGs left by Apollo 12 through 17 on the lunar surface as a heat source during lunar night - even today these radioactive containers still radiate a considerable amount of heat to their surroundings. To determine the feasibility of using the RTGs like that, we would like to get in touch with the original designers of the Apollo SNAP-27 RTG's to ask them about the characteristics of the RTG's on the lunar surface so we can produce a thermal model of the units. We need contact information for these persons. All we currently know is that they worked at General Electric. --Anders Feder 15:50, 4 January 2009 (UTC)

The RTGs are US government property. You will need to discuss their usage with various US federal agencies with jurisdiction, e.g. NOAA, State Dept, DOE, NASA. Technology of RTG will involve ITAR issues which will require export license for non-US citizens. Contacting GE will do no good, they will simply direct you the US federal agencies. Good luck. Charles F. Radley

Thanks, but we are not contemplating using the RTGs. We are considering using the heat dissipating from them naturally by radioactive decay. We are not trying to get in touch with General Electric or any federal agencies who may own the RTGs, but rather the individuals who designed the units, so we can produce a thermal model of them to determine the feasibility of utilizing this otherwise wasted energy. --Anders Feder 12:49, 5 January 2009 (UTC)

The best information I have found currently would seem to indicate that the RTGs are now too depleted to emit much in the way of heat based on the radioactive decay rate of plutonium. Was there ever any public information disclosure as to the mass of radioactive material included in the RTGs? That would have saved quite a bit of time in considering their use. Fred J. Bourgeois, III

This should be checked against more reliable sources, but the fuel capsule contained 3.8 kilograms (8.4 pounds) of plutonium-238 in oxide form (44,500 Ci or 1.65 PBq) according to Wikipedia. --Anders Feder 19:02, 11 January 2009 (UTC)

Indeed, this NASA report suggests that the RTGs degraded by around 60% in just their first decade on the lunar surface, so they must be everything but depleted now. Request closed. --Anders Feder 20:09, 12 January 2009 (UTC)