> Partial reusability won't get the cost down to the ~$100/kg range.

I don't see why $100/kg is a particularly important threshold.

> Falcon 9 can get 15 tons to LEO for $45 million, and that's already the lowest price on the market. To hit $300/kg they would need to build a 2nd-stage, launch, recover (on a drone-ship) and refurbish for $4.5 million. That's just not going to happen.

Falcon 9 reusable is 20 tons to LEO, and the cost SpaceX charges is what customers are willing to pay, not their costs incurred. Before they had reusability, the cost to make a complete, expendable falcon 9 rocket was $50 million. The marginal launch cost for a falcon 9 was approximately ~$15 million in 2020 when they were doing 20% of the launches they're doing now. They are very likely already below $500/kg. Remember this is a system that wasn't initially designed with any level of reusability in mind. A more optimized design that shifted more of the cost to the booster and which was produced at the appropriate scale would almost certainly see a further lower cost.

Falcon 9 boosters can fly back to an onshore landing pad, and Starship has already demonstrated landing back on the launch tower itself.

> If Starship fails, we are not getting $300/kg orbital costs for 1-2 decades minimum.

That's a substantially shifted goalpost. Even if starship succeeds we're still probably more than a decade out from $300/kg orbital costs being a reality. Rockets take a long time to develop, and longer still to mature. SpaceX has been working on Starship for over a decade already. Of course if we assume every rocket currently under development gets cancelled and something new needs to be started from scratch, it will take at least one full rocket development cycle time to bear fruit. But OP was worried that if Starship fails it will cause a loss of faith such that no one even starts working on another attempt for decades.

None of that would have been a serious concern had the shuttle actually met any of it's re-usability claims. It doesn't matter that it costs a bit more in fuel and initial outlay for the orbiter if you actually could turn it around with little effort or cost in a couple weeks.

Having to inspect each and every tile after every trip because they basically didn't work like initially designed was the primary failure of the Shuttle program. It also wasn't nearly safe enough, primarily due to a shitty management culture that was taking over America (and is still currently in power in nearly every business).

The thermal tile technology was for some reason believed to be dramatically easier to design, engineer, and manage than it ever came to be in reality. I'm not convinced that Starship has "solved" the problems inherent in tile systems.

The shuttle is the only rocket system that put part of the rocket above the payload. Were it not for that fatal design flaw, both fatal flights would have been survivable. The first because the explosion would have done less damage. The second because there would have been nothing above the shuttle from which something could have fallen.

That's sort of a fallacious argument though because you could say the same thing about every part of a spacecraft that is used only for the return phase of its mission.

It might be more accurate to say that the ratio of mass for re-entry equipment to the entire craft mass is too great.

But with that said I think that the ultimate failure of the shuttle was that the design wasn't amenable to low cost maintenance. A spacecraft could have a crappy payload to orbit as long as it's cheap to maintain and use with quick turnaround.

I have a feeling that should Starship succeed this will be the case with it and it will end up having a substantially lower payload than intended but will make up for it with a design that's cheap to build and maintain.

Fair enough!