Were Rocket Lab’s Electron rocket engines damaged on impact?

Question

Were Rocket Lab’s Electron Mission 26 rocket engines damaged on impact?

The photo of the recovered Electron Rocket https://arstechnica.com/science/2022/05/rocket-lab-catches-a-1-ton-booster-falling-back-from-space appears to show rocket nozzles out of kilter. Is this impact damage from the unplanned water landing?

Rocket Lab has pursued both helicopter capture and splash-down landings. Mission 26 was half way between with an aborted helicopter capture and subsequent uncontrolled water landing. The 'chute was collapsed as part of the capture, but it is not clear to me if it re-opened after Electron was jettisoned by the helicopter. Did engine damage occur by an uncontrolled water landing with a malfunctioning 'chute?

All the engines on the first stage of the Electron can gimbal to provide steering/roll control etc, so this could explain them being out of alignment - once the engines are no longer in use there probably isn't much reason to return them to their nominal positions, leaving them in whatever direction they were facing. — Rustony, Mar 19 '23 at 10:59
@Starshipisgoforlaunch ... "mission 26", not "26 rocket engines" — Woody, Mar 22 '23 at 15:30

Infinite_Maelstrom · Answer 1 · 2023-04-03T22:37:12.540

Unlikely.

Rocket Lab has successfully re-fired at least one engine from this flight, requiring minimal re-furbishing. I do not have specific sources to say that all of the engines were in a condition to be re-furbished, but logic suggests that if at least one of the engines could be refired, then the other ones cannot have been too much worse. Especially when your question is asking that the engine bells have been badly knocked out of shape - if the sea landing was rough enough to do that, it probably would have damaged all of the engines beyond re-fireability.

Two other pieces of information can be used to support this argument:

The engines on electron are gimballed (see this answer and @Rustony's comment). It is therefore likely that the engines will be misaligned after any sea recovery since the force to move the engine gimbal should be less than the force to damage the engine [citation needed].
Rocket Lab has decided to pivot to sea recovery only, based on the condition of this particular test. If the engines had been as badly damaged as you are asking, it is highly unlikely that Rocket Lab would have pivoted away from an approach that is guaranteed not to damage the engines to an approach that would render almost all engines un-reusable.

Regarding the parachute, yes, it did reinflate after being dropped by the helicopter. If it had not, I doubt the rocket would have been in anywhere near as good condition!

Were Rocket Lab’s Electron rocket engines damaged on impact?

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