Comment by JumpCrisscross
4 days ago
> They are persisting with HLS though
Through what? What experimental data do you think renders this path foolish?
Because I’m seeing a rapid-reuse heavy lift system with a fuel depot being built.
4 days ago
> They are persisting with HLS though
Through what? What experimental data do you think renders this path foolish?
Because I’m seeing a rapid-reuse heavy lift system with a fuel depot being built.
I dunno, the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12? And that the lunar orbit chosen due to available energy makes rapid extraction impossible?
"How many fuel launches" is the error margin.
If they get less performance or more mission payload, they can add tanker launches. If they get more performance or less mission payload, they can remove tanker launches.
People ran into "the design is 10% heavier than planned for unexpected engineering reasons and now we have to make hard choices" on space missions far less complex than a literal Moon landing. SpaceX has externalized the "hard choices" into the tanker count, pre-emptively.
The lunar orbit of Artemis is defined mainly by SLS/Orion's performance, or lack of thereof. The specific NRHO was a Gateway choice, and might now be dead alongside it, but by itself, Orion can't get to low Lunar orbit. Which drives some peculiar design choices.
So many (perceived) problems with spaceflight and building moon bases and the like are solved by simply making the process and cost of launching faster, easier and cheaper; the problem that NASA has always had is that each launch, even with the reusable space shuttles, cost billions and took years of engineering, planning, etc. To the point where yesterday's launch was done with (what I perceive to be) salvaged parts where the engineering was done decades ago, because engineering something new would be too expensive and take too long.
Sure, don't fix what isn't broken and all - *nix tools are decades old too after all - but still.
> the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12?
Nobody has ever done in-orbit propellant transfer or storage. We’re building it to see what those numbers shake out to, and how the propellant gets lost. (Boil off? Leaks? Incomplete transfer? Weird, unexpected degradation because space? ¯\_(ツ)_/¯.)
If it works, it dramatically reduces the cost of lunar and deep-space access. You’re saying that isn’t worth it because it isn’t certain? This is spaceflight. Nothing is certain. We have to weigh risks and payoffs. And then mitigate them. The time for mitigating this risk is this (and probably next) year. If the refuelling is dumb, the plan changes—Blue Origin is testing its own approach on the same timeline.
Like, in Apollo 11 we fucked up the lander’s fuel budget. The astronauts were literally running out of fuel because a foreseeable problem, the surface being bumpier than expected, wasn’t contingency planned for over ten preceding missions. And we’re trying to do better than just retreading Apollo, because Apollo—strategically—failed as a platform for further manned spaceflight.
> the lunar orbit chosen due to available energy makes rapid extraction impossible
Isn’t NRHO an Orion limitation? Can Orion circularise on its own?
Also, rapid extraction hasn’t been a requirement for the Moon since ever? If you want rapid extraction, plant a ship that can motor off the Moon home in one shot as an emergency-egress option down the road. In the meantime, you’re days away from help under ideal circumstances; realistically, we don’t have rescue options.
Starship might be crap. But the bets look good, and the project is on the whole no more ambitious than the original Apollo missions. The criticisms you’re raising are either fundamental to the mission architecture because it’s developing a new spacefaring capability (refueling and rapid relaunch) or cost-cutting choices irrelevant to HLS (Orion’s second stages being efficient but underpowered).