Comment by 9cb14c1ec0 a day ago
Given that the engine telemetry shown on the broadcast showed the engines going out one by one over a period of some seconds, I could easily imagine some sort of catastrophic failure on a single engine that cascaded.
Given the huge spread of the debris, it must have been a decent sized boom, no? I mean that's got to be 10's of miles wide in this video.
For context, The lower stage reportedly has 150 tons of propellant on board when it lands.
It wasn't FTS, it just blew up: https://x.com/SpaceX/status/1880033318936199643
Yeah, most likely engine bay fire taking out systems one by one. Would be interesting to compare the telemetry cutoff with the video of explosion if possible. That could indicate if the fire even triggered an explosion, flight termination being activated or just reentry heating making the tanks explode.
Who knows where it started, but the fire was definitely in the payload bay in front of the header tanks if seen through the flap actuators during ascent, after speration at ~7:45 min
The single instance of a fire that could be seen in the stream was in the hinge area of a bottom flap.
I noticed that the CH4 tank level was much lower than the O2 tank level. That suggests a leak.
Or FOD in the LOx supply lines. The methane would keep following, even with the turbopump shut down, until the valve closes. And the methane turbopump might actually keep running with reduced supply oxygen - Raptors have two turbopumps.
It could be many things, plumbing to the engines, tank leak, ect. You could see fire on the control flap actuators, so the ship interior was engulfed in fire at the same time the first engine was out.