4 ms·
Mars Direct uses suspiciously low boil-off rates for LH2. Certainly well past current state of the art. Best achievable (not flown, but could be) is 0.1%/day, a
by jccooper 11y ago
Mars Direct uses suspiciously low boil-off rates for LH2. Certainly well past current state of the art. Best achievable (not flown, but could be) is 0.1%/day, and Mars Direct wants 0.1%/month. You don't lose a lot at 0.1%/day, but it adds up.
- curtis 11y agoAt 0.1% per day, I get 30% boil-off in 1 year (0.999 ^ 365 ==> 0.694), which is expensive but probably still a net win. I don't think boil-off is a problem once you're on Mars because you can probably just use the hydrogen gas as feedstock into the Sabatier process. Which is not to say that Mars Direct isn't overly optimistic, possibly about many other things as well.