On the last Starship flight (Orbital Flight Test 2), all 39 Raptor engines started up and apparently ran correctly. On the next flight, will we see all engines operating correctly when they get a chance to do so?
This includes proper operation for the entire flight of both stages. Uncommanded shutdowns, engine explosions, and failed relights will all result in this resolving No, with the major caveat that this must be attributed to engine problems. If, as has been suggested happened on flight 2, engines fail because of stage problems, tank problems, propellant slosh, tank depressurization, or other related problems, that will not result in this resolving No.
There is no requirement for a successful landing, completion of second stage flight, etc.
If the flight is other than nominal, resolution of this will probably have to wait until after the flight for a mishap report or other credible reporting.
Previously: /EvanDaniel/on-the-next-starship-launch-how-man
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There were failed relights in the booster landing burn, but since there were so many of them, I would guess it was not an engine problem. We'll see.
@chrisjbillington imo it seemed like an engine problem? It's that or what, slosh? 97% seems high.
Ehh don't feel like betting on hard-to-resolve markets today tho
https://youtu.be/Gq7wd6QHS38?t=2194
At about 8km altitude Booster seems to lose stability. Probably a grid fin software thing. Wobbles getting bigger and bigger.
Could imagine that messed with the propellant slosh, there wasn't much left in the tank and they were trying to light 13 engines.
@Mqrius slosh was what did them in last time, so that's what I was thinking, yeah. Or anything about propellant feed in rather than the engines themselves.
Comments from Scott Manley (forget where he mentioned this, maybe his latest video) suggest something going wrong during boostback burn shutdown may be responsible for the subsequent failed landing burn relights. Hopefully he says more about this, Scott has a pretty impressive track record on figuring out things like this.
@chrisjbillington Fuel filters blocked reported to be the problem with second flight. Perhaps slosh was at least part of the cause of that. This is fuel feed in? Upgrading the filters is a fuel feed in system not an engine upgrade?
@ChristopherRandles I think that's right, since the question description here does suggest that the failed boostback relights in IFT-2 would not have counted as engine problems.
@chrisjbillington
>forget where he mentioned this, maybe his latest video
yes. but 2 possibilities mentioned, It is here
https://www.youtube.com/watch?v=8htMpR7mnaM
4m 40s to 8min 20sec has the relevant parts
Possibility 1. Asymmetric engine shutdown at end of boostback burn looked odd - just a telemetry issue mentioned as a possible alternative explanation, but perhaps this indicates some problem.
Possibility 2. Grid fin control possibly being tested high up but maybe this control was off leading to the unstable roll movement and this could cause fuel slosh or some other issue preventing engines from being relit.
@chrisjbillington Yes, the intent is that stuff like "ice in the feed lines because of water / humidity in the tank" is not a "Raptor reliability" problem.
I'm reopening the question while we await the FAA report.
@ChristopherRandles it mentions failed relights explicitly as counting the same, where it must be engine problems specifically.
Related market:
Uncommanded shutdowns, engine explosions, and failed relights will all result in this resolving No, with the major caveat that this must be attributed to engine problems.
Registering that I think Starship failed during IFT-2 because of "engine problems", interestingly the video you linked also attributes it to what I would call "engine problems" so I'm kind of curious how this is going to resolve. The first "puff" almost certainly can't be from a tank failure, I agree that it's most likely an engine failure of some sort followed by increased LOX flow. I'm not sure what else could fail, but not fail catastrophically and not otherwise lead to any other problems for a few minutes.
I think the Super Heavy explosion was probably feed system / tank problems, not Raptor.
I think the Starship failures might have been similar, I've heard rumors of premature propellant depletion. Unclear whether that was caused by an engine failure or something else; I think we need to wait for mishap reports and such.
Right now I'm not sure how this market would resolve if it had been about IFT-2.