[cubefox]

I think the main problem for Starship is that they need to do a large number of tanker launches (about 20 I believe) in a timeframe in which the propellant in the LEO depot doesn't boil off. I assume they need to develop some good sun shielding for that. 20 launches could take quite a long time (multiple months? a year?) since it will probably take quite a few years till Starship, especially the upper stage, is rapidly reusable. They can't wait that long with Artemis 3, with Sean Duffy adding pressure.

[floating-io]

On launches, it's conceivable that they can do the launches in 20 days if they do one a day. I ignore reusability, because I don't see it as required to meet the need.

They're known for moving fast, and they're building multiple pads. They're also building enormous mass manufacturing facilities in the background of all this (Gigabay and whatever). Not sure how many ships they'll be able to produce per month once the design is nailed down, but I'll bet it will surprise everyone.

SH Boosters are already effectively reusable for the purposes of this discussion; a couple of them have already re-flown. That's half the battle right there.

Boiloff prevention is presumably one of the main modifications needed for the depot. I think it's supposed to be easier with methalox than with hydrolox (which BO is using), but I have no idea the particulars of what they'll have to do there to achieve effectiveness. That said, I wouldn't be surprised if they try to cut that corner at least once; should be interesting.

The big risk that I see is neither launch nor boiloff, but rather simple fuel availability. Can they get that much methane and LOX shipped around the country that fast? I have no idea, but it seems concerning to me. Logistics...

Thing about the deadline, though, is who's going to do it faster? Blue has worse issues with their current crewed lander proposal. Nobody else has even started on one AFAIK.

My prediction is that nobody can build and fully qualify a safe moon lander with a more or less clean-sheet design in three years.

On the other hand, I can easily see Starship succeeding in a moon landing in three or four years if things go well with V3 and the refuelling research. It's a stretch -- things aren't likely to go completely smoothly -- but it's conceivable.

[cubefox]

In 2024, SpaceX had one Falcon 9 launch per 2.8 days, after having been operational for several years. The first Falcon 9 was used in 2014, and the first booster reused in 2017. It seems it will take years for Starship to match and exceed that flight rate. Of course, Blue Origin faces other difficulties, as you mentioned, and they have a much more distant deadline (Artemis 5). But at this point I don't quite see Artemis 3 happening before a Chinese moon landing, with a much simpler approach that doesn't include any complexities comparable to what SpaceX is facing with its HLS. (As others mentioned, I don't think that's a major problem, as manned space flight is mostly done for abstract prestige, and the US already had Apollo.)

> My prediction is that nobody can build and fully qualify a safe moon lander with a more or less clean-sheet design in three years.

I tend to agree, though there are possible solutions that are technically simpler (if less ambitious) than either Starship or Blue Moon, while not even requiring SLS. Though it is probably too late now to try those. It's all the more surprising that Lockheed Martin still tries to offer an alternative solution:

> In a statement to Reuters, Bob Behnken, vice president of Exploration and Technology Strategy at Lockheed Martin's space unit, said the company this year has been conducting "significant technical and programmatic analysis for human lunar landers."

> "We have been working with a cross-industry team of companies and together we are looking forward to addressing Secretary Duffy's request to meet our country’s lunar objectives," said Behnken, a retired NASA astronaut.

https://www.reuters.com/science/us-seek-rival-bids-artemis-3...

But their offer would likely be very expensive, and it would be very questionable whether it can be faster than Starship HLS. So I don't think they will receive a contract.

[floating-io]

I'll be surprised if the noises coming out of LM are anything other than PR, but it's not impossible. That said, I agree, it would probably be far too expensive if it did happen.

I look forward to seeing what happens with all this. :)