Comment by Geee
2 days ago
I'm guessing / hoping that the engine outs we're planned, or that they ran the engines with slightly different parameters to test them. If it's just unreliability then it might be a hard problem to solve.
2 days ago
I'm guessing / hoping that the engine outs we're planned, or that they ran the engines with slightly different parameters to test them. If it's just unreliability then it might be a hard problem to solve.
> If it's just unreliability then it might be a hard problem to solve.
It might, but it certainly helps having a ton of them around. Given that they used 42 of them today and 2 failed in some fashion, we'll call that a 1:21 failure rate. On a more typical rocket with say 10 engines (eg falcon 9), there's a good chance they wouldn't have seen the same failure till flight 3.
> Given that they used 42 of them today
20+10+3=33 on the booster, 3+3=6 on the Ship, total 39.
I remember Elon said they want to add 2 engines to the first stage, but that still would be 41. Where's the 42th supposed to be?
I messed up, for some reason I had it in my head that there were 9 on starship, so 33 + 9 = 42.
It’s something like up to 6 can fail and it keeps going, seems pretty good. I know they did some stuff like remove a heat tile to get failure feedback, wonder if engine was planned or accidental
Accidental since they didn’t make the sub-orbit they were aiming for and thus couldn’t test engine re-light.
Adjusted wald intv'l gives us for 2 observed out of 39 gives us a "true" failure rate from 1 in 200 to 1 in 6 (95% CI).
Very first flight of a brand new engine type (Raptor 3) with totally reworked heatshielding/plumbing/sensors/control systems/etc.
Which is true, but at the same time: this is Starship Flight 12.
The whole point of Starship is that it's a reusable vehicle with easy turnaround and quick maintenance. And in particular it's supposed to be different than the other reusable vehicle with easy turnaround and quick maintenance, which turned out to be sort of a boondoggle.
Yet, they've now hand-built and destroyed twelve of these things across multiple redesigns, and it still hasn't completed its design mission once. In fact basically every launch has unexpected major failures.
As poor as its safety record ultimately ended up being, the shuttle launched successfully on its very first try. And we only had to hand-build five of them. And lost two, sure, which is still a lot less than twelve.
Yes yes, I understand that iterative design has merits and that the ability to rapidly prototype and try things in the stratosphere allows for less conservative tolerances and better ultimate performance.
But does it really take 13+ tries?! At what point to we start wondering if we have another boondoggle on our hands?
If you can afford it, I'm sure anyone developing a rocket would prefer to do it this iterative way. I don't really understand the complain.
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But all of those 12 launches happened in just 3 years, and cost a tiny fraction of other major spaceflight development programs.
For reference, SLS has been in development for 5 times as long, and cost 15-20 times as much, as Starship, and they still haven’t landed people on the Moon, which has been one of the stated goals since the Constellation program in 2005.
I don’t see how the number of failures matters if the end result still happens faster and cheaper than anything else.
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