If they can't prove rapid reusability for both stages, it's extremely unlikely the cost will be anywhere close to as cheap as current estimates. And if they can't refuel in orbit (which as of now, has only been performed a handful of times with small satellites), Starship will be unable to leave Earth's gravity well.
If the first stage is reusable, having a cargo launcher second stage that is none, reusable can be done for 30M.
First stage reuse is wall proven already.
> Starship will be unable to leave Earth's gravity well.
If its not reusable you can use it like any upper stage and it could launch anything anywhere you want.
> And if they can't refuel in orbit (which as of now, has only been performed a handful of times with small satellites)
The physics is well understood. We do it constantly with non cryogenics.
I really think this is overrated in how much of a technology risk this is. Specially if you have enough weight that you can invest in the solution.
Refueling is a schedule risk, maybe the first design will fail to account for something and it will take a couple iterations to get it right. There is zero risk that the problem is unsolvable.
In general I think refueling is a far smaller problem then the heat shield.
One, it's Congress' baby.. ain't noone taking it out behind the barn.
Second, you need redundancy. If something is proven bad with falcon or starship design... You don't want another situation like we had with the shuttles where your paying for Soyuz seats for years on end while the problem is debugged and mitigated.
Iirc, NASA is trying to shift SLS production to the private sector, to try and "get rid" of this ugly duckling.
No you don't. Just as there was no redundancy for Saturn V. As there is not for Falcon Heavy. There was no redundancy for Delta 4 Heavy. There is always a largest rocket.
And if you do need redundancy, SLS is not how you would get there.
If Starship doesn't work, then there will simply be no moon landing. Period.
> Iirc, NASA is trying to shift SLS production to the private sector, to try and "get rid" of this ugly duckling.
That is just contract mombo jumbo that changes nothing about the actual project.
No, what happens is that you create a seriously powerful group of private institutions that will go full force into lobbying congress to not kill the project. Even more so then now.
But it would be increasingly awkward for Congress to be seen to force NASA to choose the $2B launcher from vendor A over the $10M or $50M (or whatever) launcher from vendor B.
And for what it is worth, SLS should be canceled no matter if Starship exists or not. Its a program that embodies everything bad about the modern space industry and space policy.