First Base

Options for First Base

• A first base on Luna might be located at one of the Peaks of Eternal Light at the Lunar North Pole. Access to sunlight for solar power all summer and most of the winter would help maintain operating temperature for the machinery. The landscape might be too rugged to provide a convenient rocket landing area and base site the right distance apart.
• Another possibility is to put a base in the best flat place with a covenient area for rocket landings, and provide Nuclear Power. There have been some political difficulties with nuclear power in space in the past.
• It might be most economical to make a first base away from the polar region of Luna, a base for remotely controlled devices. The six month nights at the poles require some power source, such as people might get by establishing a power distribution grid of solar power stations ringing the pole at a distance of about fifty miles. Such power stations ought to have solar cells facing away from the pole on convenient hills. The trouble is that people would have difficulty establishing the grid during the five months that we can count on solar power at a lunar pole. A power station atop a 2000 foot tower could provide power through the lunar polar winter, but that would be no cinch either.
• The “Long Endurance Rovers” article Thermal Management section gives a scheme for rejecting heat from a radiator on Luna away from the poles. The radiator is protected from sunlight and from infrared radiation of the landscape. Basically the radiator is set in a wall in an east west running ditch of parabolic cross section lined with shiny aluminum foil. The axis of the parabola coincides with the wall and is tilted away from the vertical toward the equator by an angle equal to the latitude. The top of the wall is below the focal point of the parabola so that all of the sunlight falling in the ditch is reflected back into space. This sort of radiator could be used to reject the heat of a hydrogen and oxygen liquification plant. So these gasses could be conveniently stored for use in fuel cells during the two week and eighteen hour night. Cryogenic tank insulation is not much of a problem on Luna where vacuum is all around. Just pack the liquid hydrogen tank in a couple of feet of fines sifted from the regolith and that should suffice. Water from the fuel cells would build up during the night and need to be stored in a tank where it will not freeze. Solar cells would power electrolysis during the day to recover the hydrogen and oxygen, and power the liquifaction process. There is considerable loss of power in storing it for reuse this way, but it is all stuff people know how to do.
• Add up the requirements. The tankage, the liquifaction plant, the protected radiator, the fuel cells, the supply of liquid hydrogen and oxygen, the thermally insulated building, the electrolysis unit. For a small base that could actually be shipped to Luna it is still less costly than the polar power tower or an entire power distribution grid. Start small and build up to the power distribution grid over a period of a few years. Meanwhile rovers could have some place to stay at night where they won’t freeze to death. There would be no major activities at night, just enough power to stay alive. Naturally the elaborate pressure vessels with air locks and plumbing necessary for people ought to wait until there is more time to provide such out of mainly lunar materials.
• One possibility for the shelter which would be a major feature of a first base would be based on structural members that are cloth tubes stuffed with regolith. The tubes could have their seams laced up as they are filled with regolith, then more regolith piled on top. Only the cloth needs to be sent from Earth. The advantage of this type of construction over inflated structures is less vulnerability to small leaks. A disadvantage is longer construction time. More substantial buildings (as described in Sintered Brick Construction) could be built from local materials when there is time to develop some industry. Remote controlled rovers and manipulators could set out from a base over a few years and establish a circum polar power distribution grid within a possible time frame. From that point the requirements for Bootstrapping Industry should be clear.
• Reference