Rocket launch marks big step in building China’s lunar infrastructure

Queqiao-2 will relay data between Earth and Chinese spacecraft on the far side of the Moon.

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[uhuznaa]

According to Eric Berger's anonymous source it is highly likely, that after few launches NASA will drop SLS and Orion and switch to Dragon + Starship.

1. HLS launched to LEO
2. refueled
3. astronauts launched to LEO on a Dragon
4. dock HLS
5. Earth-Moon-Earh roundtrip on HLS
6. Dragon launched to LEO
7. dock HLS
8. astronauts splash down on a Dragon

Even if Blue Origin enters the game they'll go a similar route (maybe with Starliner, hopefully being flight approved till then).

There is no rational reason to keep SLS on the long run, even if costs are not considered, one launch per year is obviously not enough to mainain continous present on the Moon.

How do you do an Earth-Moon-Earth roundtrip on HLS? It just lacks the delta v to return to Earth from the Moon surface and brake into LEO to dock with a Dragon there. Maybe you could use aerobraking with HLS on the return leg instead of propulsively braking into LEO, even without much of a heat shield, but this would mean to expose the crews to quite a lot of radiation (and time and risk) by flying them repeatedly through the Van Allen belts, and still would be more than marginal.

I mean, yes: SLS plus Orion is incredibly wasteful for just getting a crew to a Moon orbit, but it's not THAT simple.

Of course even having to use several Starships (even expendable ships with a third stage or propulsion module for the return leg) would be so much cheaper than one SLS/Orion launch... Like replacing SLS/Orion with an expendable Starship that carries a third stage consisting of a propulsion module and a Dragon capsule for the round trip to and from lunar orbit and with a direct reentry on the return leg.

But you can't just launch even a fully refueled HLS from LEO to the Moon surface and back from there into LEO. OK, maybe later (bigger) Starship iterations may improve on that, but this is pure speculation.

OK, whatever the solution is I'm fairly sure that SLS won't appear in it for very long... And the writing really is on the wall, even with all the "Musk's rocket fails again!" bullshit headlines everyone with even half a working brain meanwhile should have understood that SH/SS is viable, and that at a fraction of the costs of SLS.

WRT China: I like that they accept the challenge. I think they know very well that space is the high ground in every way and that they just can't afford to fall back like a dropped booster like Russia or the EU do. And honestly I have very little political qualms about all that. Our democracies aren't exactly unblemished, China has managed to do a whole lot of good for most of its population in the last 100 years and who knows how all of this looks 100 or 300 years into the future. I rather take the long view on all that. And competition is a good thing to have. Without China pressing forward here the US just may never have bothered with the Moon again, much less anything else in space (apart from keeping the pork trains running).

 

[uhuznaa]

If we're flying to the moon every week, it's not going to be a Starship doing it. You're looking 100+ tonnes of metal that are flying to (and presumably from) the moon for each trip. That's a ton of refill missions. One doesn't need 100 tonnes of structure to hold 100 tonnes of payload + the requisite propellant to land and lift off the moon. Something 1/5 that mass could suffice potentially.

If the tankers are routinely reused the dry mass shouldn't matter much. Propellants are cheap. But yes, an expendable Starship with a light third stage and some smallish engines instead of the payload section would be a rational way to deal with this. HLS being based straight on Starship is pretty much just a cost-cutting approach for SpaceX as far as development efforts are concerned with Artemis as planned by NASA. They bid with what they were meaning to build anyway.

Also to land and to lift off from the Moon isn't all, you also need to get there in the first place from LEO. A fully fueled Starship (without heat shield, flaps etc.) fits the bill nicely, even if it may have too much thrust and with this too many engines.

 

[uhuznaa]

The mass of Ship is enough to withstand 6+ g's of acceleration. An ideal landing and launch on/from the moon is probably closer to 0.5 g. So it's not just that there's too much engine (there is). It's also that the wall thickness of Ship is perhaps 10 times higher than what is necessary for the loads that will be experienced from LEO to the lunar surface. Now instead of launching tankers every day+ you're launching perhaps twice per week. While propellant is relatively inexpensive, the launch costs and range availability are a concern.

Yes, but as it stands now HLS sorties will not be a regular thing in any way. HLS is quite braindead as just a dedicated Moon lander, but it's based on Starship, which WILL be a regular thing to fly.

Designing a dedicated (and substantial) craft to fly only a handful of missions and that is good for nothing else than that isn't the way SpaceX is doing things. They just bid on this because it halfway looked as if it could work, would earn them some money, allow them to gather experiences and nicely pad their launch cadence. I doubt that SpaceX cares very much about going to the Moon at all in itself.

I agree that a lightweight and possibly hydrolox stage could be much more efficient for this task. Just let BO do this if they can.