Practicality of moon base

There has been much talk of late as to whether it is desirable for NASA to return to Earth's Moon, or to skip it and spend the money on a manned trip to Mars.

There are several reasons for wanting to return to Luna. First is, to provide the feeling that we (The USA) Can still do it. This is a highly emotional reason, and for that, it should be suspect. Other explanations are to 'lay claim' to the moon, ahead of Chinese landings and potentially Indian ones as well. This claim would also explain an idea that NASA needs a permanent moon base (presumably, a manned one). This is a more credible reason to go to Mars, but also one which has great expense for the mere posturing in International politics and a dubious land claim. But, it is forward thinking.

Forward thinking is important. A trip that is ill-conceived and under funded will be useless in the long term. Yet, anything more than a "flags and footsteps" mission will be expensive, and without proper forethought could be a 'moondoggle' (moon + boondoggle). A moon base can function as a foothold on space, but hopefully not just for one country but for all. I will consider what the moon can offer for 'steps farther out'.

The moon has 1/6 the mass of the earth, and therefore 1/6 of the gravity and therefore requires much less energy to launch from. This could make it attractive as a 'depot' for missions to other destinations, but if that were the only purpose it were to serve, why not build a space station to use as a depot? A space station has no gravity worth speaking of, and is also free from the danger of moon-dust fouling up systems.

The moon may contain some water. However, it may be more trouble to obtain it than it is worth. It may be easier to bring water up from earth, or obtain it from free-floating places in space, such as in the tail of comets. Were it found to obtain large amounts of water that were easy to tap, then a "moon well" would be valuable indeed.

Helium 3, which is 'regular' helium plus a neutron, is more plentiful on the moon than on earth, but is still only available at ten parts per billion. It has potential use in generating power, using 'aneutronic fusion', which is a reaction producing no neutrons, and therefore no waste or reactor degradation. However, no fusion reactor has yet shown to produce more power than it consumes. Even if a practical fusion reactor is developed, fuels other than He3 may prove to be more practical. Building a moon base to provide He3 when there is no demand for it would be overly speculative, and a potential moondoggle.

The function of a moon base which is most practical is that of mining for traditional metals. The metals iron, aluminum, and titanium are present on the moon in concentrations which may make mining and processing them inexpensive, when comparing the cost of bringing these materials from Earth. Oxygen is also obtainable from lunar minerals, as is the aformentioned Helium3. In addition to refining the minerals, it may also be possible to use them in their powdered or solid form, by creating a 'lunar cement' or 'lunar concrete'. Such a concrete may be useful for ablation shields.

I believe that the priorities of NASA's lunar missions should be directed towards providing mining and manufacturing facilities once a base has been established. There should be an effort to keep the number of personnell required on the moon to a minimum. It may be more practical to launch robots to the moon with specific missions rather than set up a manned base. Research ought to be conducted towards the tradeoffs of manned versus robotic missions.

I foresee a future where the large and massive portions of spacecraft, such as the hull with radiation and ablation shields, are manufactured on the moon. Less massive and complex equipment is brought to the moon, where final assembly occurs, followed by launch. Over time, more manufacturing is transferred to Luna. Spacecraft resupply of metals, oxygen, and possibly water may be from Luna and not earth.

What Mars can provide in terms of furthering human exploration of space is less clear. Its mass is not so much less than Earth's as to make use of its water particularly attractive. It may have hydrocarbons of some value, but these might be better obtained from Titan, or other Jovian/Saturnian moons where they are far more concentrated and escape velocity is far less.