More thoughts on lander fuel

As people following the "Don't get sore" thread know, I am an advocate of
putting a permanent colony on the moon, with one objective being to launch an
ambitious mission to eventually explore the entire Solar system.

One thing that is troubling me is fuel for the landers. The stuff needed is
very rare on the moon or not present at all. Lander fuel is bulky and massive,
the sort of stuff we really don't want to boost from Earth if we can help it.

Can our first stop be one of the comets perhaps, and we chip off some ice? We
purify it into plain old water while in transit, and when we get into orbit we
electrolize it and liquify both oxygen and hydrogen. This does limit our
surface duration though, since both of these boil off.

The Apollo fuels contained nitrogen and carbon, both hard to find on the moon.
Maybe we can find enough to synthesize our fuel though, or maybe we can send
them from Earth when we are launching the rest of the stuff. It should require
less launch capacity than actual lander fuel.

Another possibility I have discussed, at least for lunar rocketry and perhaps
even for these landers, is a hybrid solid/liquid fuel rocket using magnesium,
aluminum or an alloy as solid fuel. They both burn, but I don't know if the
reaction is energetic enough to get enough thrust to be practical. Pump in the
oxidizer and light it up. Does anyone have any opinions on whether this would
work? If it would work, it is an attractive concept because aluminum and
magnesium are both abundant in the moon, unlike things like carbon, hydrogen
and nitrogen.

--
Ferengi rule of acquisition #192: Never cheat a Klingon...unless you're sure
you can get away with it.

LV Poker Player wrote:

 > One thing that is troubling me is fuel for the landers. The stuff
 > needed is
 > very rare on the moon or not present at all. Lander fuel is bulky and
 > massive,
 > the sort of stuff we really don't want to boost from Earth if we can
 > help it.

_Moonbase_ by Ben Bova talks about this. One possibility for travel
around on the Moon would be mining Al and O and using them as fuel, both
of which are available on the Moon. They wouldn't get a huge specific
impulse, but they'd be enough for getting around on the Moon itself, and
would help a lunar colony pay its own way to some extent.

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