Guy_PCS OP t1_je5owcu wrote on March 29, 2023 at 4:26 PM

Article excerpts;

The SLS was running late and over budget. Congress had put its thumb on the scale; a program this large can benefit every state and district in the country, so politicians can’t resist pork barreling it — even to the point of failure.

Lest we forget, the Space Shuttle was billed as inexpensive, safe, and reliable. It was many things, but it was none of those things. SLS seems to be making those same mistakes.

SpaceX also wants Starship to take humans to the Moon on its own. If that’s successful, then it’s possible NASA might consider replacing SLS with Starship.

Water had been found in the form of ice buried in deep craters at the Moon’s south pole, and further research showed there could be billions of tons of it. Humans have this inconvenient need to drink and breathe. Water can satiate the former, and breaking water into its atomic components can provide oxygen for the latter. As a bonus, the hydrogen in water molecules can fuel rockets. It is not hyperbole to say this discovery is one of the most important findings of our age. Science and engineering efforts to investigate growing plants on the Moon, piping oxygen from the south polar mines to bases where humans will live, using the regolith — the pulverized lunar rock covering the Moon’s surface — as a building material for habitats, and more.

cjameshuff t1_je5sbf3 wrote on March 29, 2023 at 4:47 PM

> piping oxygen from the south polar mines to bases where humans will live

Regolith is roughly 50% oxygen by mass, it will be far more practical to just crack it out of minerals than pipe it across the moon from polar craters.

Water can be cracked into hydrolox propellant, but Starship doesn't use hydrolox, avoiding it due to the difficulty of handling and storage and its low density. At any rate, the great majority of the propellant mass is actually oxygen, which...again...can be obtained anywhere on the surface. Starship could take on lunar oxygen after landing, getting 78% of its return propellant from lunar sources, without any dependence on polar ice.

Which is good, because it's not certain there's enough easily-accessible ice at the poles to burn as rocket propellant. It may be better to conserve it for uses on the moon itself.