Well, first of all, oh crap.
Second, there are advantages and disadvantages to both materials. Carbon fiber is lighter and stronger and doesn't flex. It's also an order of magnitude more expensive and much more difficult to produce in quantity as SpaceX is doing with the steel starships.
The rough scale of thousands of starships launching per year, turn around times of several hours etc., is basically why they switched I think.
60 times cheaper, and pretty great with temperature gradients; the 'old' stuff won over carbon fiber basically.
https://everydayastronaut.com/stainless-steel-starship/Quote:
Now you might be thinking, "If the entire system is reusable the cost of the rocket doesn't really matter as much, does it?" Well, of course that's true to some degree, but forget the physical benefits of stainless steel, if something is 60 times cheaper, it can really quickly affect your bottom dollar. And SpaceX is, after all, a private company looking to make a profit at the end of the day. Sure, they could spend 10 years developing the most advanced carbon composite fuselage ever that costs insane amounts to produce, but let's look at where that'd get them in 20 years. Now they lost a lot of time of potentially profiting off the development of a fully reusable vehicle, and THEN they'll have a rocket that's even more expensive to build!
We're once again seeing SpaceX not fall into the trap of the sunk cost fallacy. I talked about this quite a bit in a video titled "Why does SpaceX keep changing the BFR" after we saw its third big change in design at the Dear Moon announcement in 2018. But the fact is, this all checks out. It might be easy to think this is a disappointment, a letdown or a compromise, but quite frankly it IS a compromise.
Engineering is always a compromise. And that's not a bad thing.
There's trade offs to absolutely every single decision whether it be time and money, or whether it be a flight profile where it might make sense to throttle down at a certain point, to trade offs in strength and weight of certain materials. There are ALWAYS trade offs!
But to your other point, the flip at the end is indeed impressive, and I hope it reliably works well in the future. However, an upper stage surviving re-entry is always to me more impressive from a sheer engineering perspective (the only human built things to have pulled it off are capsules, I think, and some film parachuted down). That huge mass has incredible forces on it to pull it off, and it must both be controlled, and not suffer any single point of failure during several critical minutes. Aerobatics are pretty visually, but not anywhere near as demanding. Again, just my opinion.
