Size of Infrastructure

From "The Machine Stops" to Nano-assemblers

• There are two fictional visions of reproducing industrial infrastructure that are near opposite ends in scale. In a story "The Machine Stops" E.M. Forster in 1909 depicted all people on Earth and all of their machines interconnected as one self sustaining growing unit. Eric Drexler and others suggested that a desk top scale nano-assembler (once one was perfected) could make other nano-assemblers from the appropriate raw materials and power; and thus be a full reproducing industrial infrastructure to fit in a moving van. God has already got one up on Drexler with the carrot seed.
• Opponents of putting industrial infrastructure on Luna tend to Forster's vision. They seem to think that if an industrial infrastructure is not as big as the Earth including as many people as live today, it cannot sustain itself and produce product, and since it is impossible to ship such to Luna, people should not try.
• Some proponents of industrial infrastructure on Luna seem to think that fully self maintaining and self reproducing industrial equipment could be sent to Luna with (perhaps) a half dozen Ares V launches, with these launches including (perhaps a half dozen) astronauts who will be living in locally built housing and running the show the same week that three of them arrive on the first Ares V trip. They could be imagining an industrial base something like Drexler's table top nano-factories to support all the needs of astronauts from the start, or they could imagine that congress will cheerfully keep sending tang and freeze dried filet mignon to Luna for years. Actually the way to kill a government funded space program is to insist that the program simply must have resources that are more expensive than congress is willing to provide. The job of any engineer is to solve a problem while working within certain constraints. The tighter the constraints in which something can be accomplished, the more cost effective and/or profitable that accomplishment will be.
• Actually neither Drexler's nano-factories nor Ares V launchers are necessary to build a lunar base that can support people. Time and remote controlled equipment that neither eats nor drinks nor breaths can establish the infrastructure that can support people and allow the export of products that will pay for imports. That is perhaps fifty years before there are profitable exports, not quite so long before the considerable benefits of hands on work can aid the lunar enterprise.
• All necessary remotely operated devices can be sent to Luna on moderate size rockets. The Delta IV heavy can put 19000 pounds into low Earth orbit.(as compared to a planned 350,000 pounds for the Ares V) A modest modification to make the rocket more appropriate for the low Earth orbit mission than the Geostationary orbit mission could improve on that. A useful unmanned space station that would provide a platform for vehicle assembly and refueling would allow 19000 pound payloads to be assembled with a fully fueled vehicle that would put 19000 pounds on Luna. A useful unmanned space station would have a constantly rotating portion housing motors, storage tanks, solar cells, communications equipment and if necessary some structure and ballast that would increase the moment of inertia for the constantly spinning portion. There would be a spin up spin down portion to rotate on the same axis. A counter rotating section would allow the section intended to be nonrotating to remain so without using rocket thrusters. The nonrotating section would have solar cells and communications equipment. Cargoes of fuel and rockets to be refueled or assembled would dock with the spin up spin down portion while it is not rotating. Docking of two spacecraft was demonstrated early in the space program. The center of mass of the loaded platform would be adjusted to the common spin axis of the station. The platform would be spun up to a mere 20 centimeters per second squared radial acceleration and fuel would be transferred with no problem. The two sections of the refueling station would be connected by magnetic bearings and an electric motor. There would no solid surface contact between the two and no need for lubricants.
• Savings comes from not building Ares V nor maintaining launching facilities for Ares V nor any other excessively large and expensive vehicle. More savings come from a higher frequency of launch of medium lift rockets resulting (at least potentially) in lower unit cost. NASA does not do things this way because of an institutional bias toward using big rockets. There is some argument for using big rockets in all at once launches for manned Mars missions, but the expense should all be counted toward the manned Mars missions. A program of Bootstrapping Industry on Luna does not require big rockets.
• This does not need to result in a smaller NASA. Spending the same money on cheaper per each missions results in more missions.

A Lack of Data

• There is good reason to believe that the Ares V was just too big and expensive for a practical space program, but how big should a rocket be to fit well with NASA's programs? Some might think that a rocket similar to the Ariane V ES with a 46,000 pound to LEO capability would be sufficient. Others might consider that the Falcon_9 Heavy with a planned 71000 pound to LEO capability would be better. If people oppose space colonization on principal, then anything larger than needed for communications and military satellites is considered a waste. Numerical matching of requirements and the ways of meeting those requirements is needed to get a good general idea. All in one launch missions should be compared with multiple launch with assembly on orbit missions by the service to the over all goal and by cost.
• How big does an industrial base on Luna need to be to be mostly self-replicating? The Advanced Automation for Space Missions starts to address this question and others.