Henry Spencer wrote:
> No settlement; Apollo-style missions, although probably with bigger crews
> and longer surface stays. And that's *fuel*, for TLI, LOI, and landing,
> not resources for surface use. I don't know exactly how large a vehicle
> they had in mind, but 100-200t of LOX/LH2 needed in LEO would be a
> reasonable first guess based on Apollo (which used about 80t, but also had
> 30-40t of hypergolics on board, mostly for LOI and landing).
So they planned to launch water (likely on the shuttle) crack it in
LEO and use it as fuel to get to the Moon? O.M.G. No wonder they need
$100 billion to return to the Moon. (Shaking head disapprovingly.)
> > This is ridiculous.
>
> No, it's electrolysis. Electrolysis is *horrendously* energy-intensive.
> At 100% efficiency, you'd need just under 16MJ/kg to decompose water...
> and with electrolytic processes you're lucky if you get 50% efficiency.
> (I don't have current industrial numbers for water electrolysis in
> particular.) So perhaps 35MJ/kg, or about 10kW-hr/kg, if we're lucky.
I don't remember it being that hard in high school chem class, but
that was 25+ years ago. Ok. It's hard to crack water.
> They'd be useful regardless. Oxygen is much easier to ship. If you're
> averse to LOX for some reason, lithium perchlorate is 60% oxygen by weight
> and decomposes on mild heating; that's what the Mir/ISS backup oxygen
> generators use. Or you can use hydrogen peroxide; it's not as good an
> oxygen source, unless you resort to electrolysis of the water, but the
> water may be a useful byproduct. If nitrogen is more useful as a
> byproduct, consider N2O or (ugh) N2O4. HNO3 will give oxygen, nitrogen,
> and water, although not quite as easily.
I wouldn't be using LH for fuel (HTP/Jet-A is my choice) but to
support the lunar colony I'd just ship LOX or lithium perchlorate or
HTP (which is a GREAT source of oxygen if you catalyze it). HNO3 has
benefits too - the Moon needs nitrogen if you're growing food.
Michael
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Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED]
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