The "completely unrelated rocket" will not be certified to launch Humans in time. The modified Starship that is used as a lander will undergo some certification, but ferrying Humans from lunar surface to lunar orbit is a lot less difficult and risky than blasting off of Earth.
The only thing SLS currently adds to the moon mission is that it allows the switchover between capsule and Starship to happen in lunar orbit instead of LEO. This is not very valuable.
SLS+Orion is ready to fly now, or at least almost.
One small exception is that transfer of people in Artemis III will be from Orion to Starship instead of from Crew Dragon to Starship.
After Artemis IV the plan is to transfer people from Orion to Lunar Gateway to Starship.
Not 100% sure but I think metal has not yet been bend on Lunar Gateway.
Citation needed.
NASA specifically called out in their report that SpaceX had done a huge amount of work on refueling already and they were impressed with the amount of detail.
NASA has also handed out contracts to study fluid dynamics of cryo and SpaceX got a contract to study that.
This is not some mystical thing. Refuling in orbit has been done for 50 years. Yes, its now cryo fluids but pumping cryo around in orbit is already required for upper stages, so its not really even that new or different.
And btw, refueling Starship is a required part of Artemis if you want to transition crew in earth or lunar orbit.
This didn’t age well.
Yeah, Starship hasn’t stopped blowing up. What it has flown successfully is a small atmospheric hop, with a pretty pared down version. The first stage hasn’t even successfully static fired yet. And yet, everyone is falling over themselves to say various versions of “SLS is obsolete because starship”. SpaceX has a great track record in developing Falcon 9, its reusability, and Dragon. But Starship is order of magnitude more complicated, optimistically it will not fly for several years.
I remember in 2017 when people said Falcon Heavy is not real, SLS is and all this bullshit.
SLS has no logical justification, even if either Falcon Heavy nor Starship existed. It just doesn't make sense if you actually think threw the problem.
NASA knew this, and didn't want (outside of Johnson) but were forced to do it.
> But Starship is order of magnitude more complicated, optimistically it will not fly for several years.
That quite the claim.
I would bet you 10k$ that Starship will reach orbit 5 times before SLS reaches Orbit twice? Interested?