starship fire

[North]

Does anyone know why the second stage of starship flight test 7 caught on fire? also 10 and 25 mintues after the booster landed it caught on fire does any one know why? apparently the second stage burned up over turks and caicos is this ture?

 

[Hevach]

Anything official will have to wait for an announcement.

However there's room for an educated guess. Flight 5 had a very similar fire on the booster - during the capture burn plumbing in one of the chines ruptured, blowing a hole in the side of the rocket and destroying at least one engine in the process. That time the rocket was doing its shortest and lowest energy burn of the flight and there wasn't much fuel left anyway, so it just hung from the catch arms burning for a while.

There are fuel pipes running close to the hinges for those rear fins. An internal fire near where those pipes should be could indicate that plumbing also ruptured. This time the rocket affected was in its longest and most energetic burn, so it was only a matter of time before something bad happened. Maybe the fire broke through into the fuel tank, or maybe the multiple engine failures tripped the flight termination system, which released the entire fuel and oxygen load right onto an open flame.

 

[North]

Thanks. Do you know if the booster will be able to reused?

 

[Hevach]

I don't think so. They did reuse one engine from flight 5 on this booster but so far the vehicles themselves are subjected to "destructive inspections" after flights to isolate any issues that would impact reusability.

This landing seemed to go flawlessly, so if they were going to stop it wouldn't be the worst time. But every vehicle has still had some level of structural changes and I expect those to receive due scrutiny before they try actually reusing one. There's a lot of daylight between looking perfect and being perfect.


Also incidentally there was an initial statement given, and the educated guess was not far of. The fire was from a broken line, but it's believed to have happened between the bottom of the tanks and the engine plate. Fire can still escape from there through the hinge as we saw in the video. It might also be a better fit for the engines failing one at a time - the lines I guessed are arranged in two groups of 3 and you'd expect a cluster of 3 engine failures if one is burning. We saw at least five fail one at a time.

That covers the "what" and "when," the FAA announced an investigation so we'll hopefully get the "why" later.