Water, probably sea water is easier to handle. Its freezing and subsequent expansion should also be relatively easy to deal with. However, what to do with the leftover salt?
The 215 KW needs about 1,000m2 of solar array weighing a mere ton. With the appropriate deployment technology (http://forum.nasaspaceflight.com/index.php?topic=18022.0) this array could go up on a Falcon 1 (depending on where sited, of course).
Quote from: alexterrell on 07/28/2009 11:12 pmThe 215 KW needs about 1,000m2 of solar array weighing a mere ton. With the appropriate deployment technology (http://forum.nasaspaceflight.com/index.php?topic=18022.0) this array could go up on a Falcon 1 (depending on where sited, of course).Based on what? These mass and volume estimates are laughable. There hasn't been any arrays with that weight. Falcon 1 as an LV is a joke. Power conditioning and batteries have been ignore.
Water > Hydrogen and Oxygen needs 285KJ / mole. Accounting for inefficiencies, call it 500KJ/18g. Let's say you want 20 tons per month of fuel for visiting launchers (this is the same as in the Profac Revisited thread - http://forum.nasaspaceflight.com/index.php?topic=17984.0). So in one month you need 5.55E11 Joules. Assuming constant power, that's 215 KW of electrical power needed. If you're in Low Earth Orbit, you need to double that.
The energy required to strip water into LOX and H2 is huge. Especially if you intend to burn it and not use it as part of a closed cycle system, ie. fuel cells; you'll obviously want to do the energy intensive stuff here and launch components only. On the other hand, if you have a closed cycle system, you need to be able to crack water anyway so you need to have the equipment including the power source for this in situ and what exactly you launch, water or components; doesn't matter so much.We need a way to store vast amounts of energy for any extended stays on the Moon. Solar and a closed water cycle might serve until there's a reactor in situ but a SAFE type system makes more sense, IMHO.
YI can't do the math, Alex, but you may be able to. Tighten up on your array estimate, and Jim will have to agree, if your calculations are correct.
I agree there'll need to be additional equipment, but am baffled why Jim thinks batteries are needed for this.