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start the most advanced rocket engines (full-flow staged combustion cycle engines [1]) Well, not. During SN9 flight, one engine could not be re-lit, so SN9 cra
by HarryHirsch 6y ago
start the most advanced rocket engines (full-flow staged combustion cycle engines [1])
Well, not. During SN9 flight, one engine could not be re-lit, so SN9 crash-landed. During SN10 flight, the two engines that were needed for landing were lit, but there was an imbalance in the fuel mixture, one engine burned noticeable more yellow than the other, and now this. You'd think they'd analyze telemetry data from flights and on-ground testing and improve their design, but visibly they don't.
And they are on notice already from the FAA for routinely blowing stuff up near a populated area.
- vardump 6y agoWasn't SN11 already completed when SN10 failed? SpaceX has a production pipeline, they're working on multiple rockets in the same time. The lessons from SN9 and SN10 are probably incorporated SN20 or even later version. (Or corresponding versions of Raptor engines.)
- PeterisP 6y agoThe key parts of SN11 were manufactured before SN9 was launched, obviously it can't incorporate design feedback from that. SN15 (the next launch) has a tweaked design of engines, but once again they are going to have multiple launches with these specific engines even if data from the first launch suggests some improvements. In fact, they had originally planned to do even more testing with this design (SN12,SN13,SN14 which had a bunch of work already done).
- avmich 6y agoF-1 development included creating a particular debugging technique for rocket engines - bombs were put into chamber and exploded to create instabilities, so engine dampening capabilities were tested. I wonder if while making Raptors some interesting techniques were created. For F-1 the result was so good the production engines routinely dampened instabilities, so Saturn-V didn't have this kind of problem in flight. Raptors seem to be less developed - of course, they have much higher chamber pressure and efficiency...
- DennisP 6y agoThey're having no trouble starting the engines on the ground, for launch, like any normal rocket company. They're having some trouble restarting them on landing, because getting the fuel to flow properly with that dramatic flip in the air is a bit of a challenge, which nobody else has ever attempted.
- HarryHirsch 6y agoEngine relighting in zero gravity is routinely done these days. All current upper stages do this.
- greedo 6y agoYeah, I'm sure they're ignoring telemetry data. They probably just go outside with a few polaroid cameras and capture pics. I can't tell if you're trolling, or if you're serious? SpaceX does an incredible job of instrumenting their rockets. They do plenty of "on ground testing" of Raptor, but some things can only be tested during flight.
- ctdonath 6y agoHow often does software run perfectly on the 1st-4th try? FAA gives launch approval knowing full well what can, and does, go wrong. It’s FAA’s job to deny on the slightest justification of risk notice.