Tuesday, July 12, 2022

SpaceX's Booster 7 Explodes

Yesterday afternoon, around several hours into a road closure and testing regime on Booster 7, something went clearly wrong. 

Watch your sound; it's pretty loud.  I recommend watching it full screen at least once.  The explosion was followed by some sort of fires afterwards, putting up dark black smoke which implies something rich in carbon.  Spilled liquid methane?  I don't know but let's assume it wasn't a used tire dump, like in Springfield, near the orbital launch mount. 

The fire burned itself out but another started about an hour later.  Booster 7 apparently dumped a large amount of cryogenic liquid, producing a flood that spread around the adjacent pad.  We don't know exactly what it was - just oxygen, methane, or both - but the cryogenic dump appeared to cause a fire to start about 100 feet (~30m) from the booster and orbital launch mount.  The fire burned for about two hours, and while no one was at the pad, if the fire had gotten blown in the wrong direction, it could have made things worse.  I was watching it yesterday by rewinding the Lab Padre camera, but didn't think to write times down.  

Within a few hours, Elon Musk tweeted out a cause they had diagnosed, an issue with the way the Raptor 2 engines are started.  

There hasn't been much information released yet on critical things like how much damage the booster or the orbital launch mount sustained, but I'd be surprised if there was none.  SpaceX operates with the philosophy that if you're not failing at all you're not innovating enough.  With that mindset, they have a better chance than other companies to figure out what went wrong and how to get back on track. 



  1. Could it have been a battery? I've learned recently they'll reignite after you think they've burned out or been extinguished.

  2. And that's why you test incrementally . . .

  3. SiG, the spin start test involves pushing real Methane through the engines (they are closed cycle) to spin up the turbopumps, and it would appear that there was an ignition source of some kind that finally ignited the methalox vapors - it scorched the paint, produced a big bang, but no real bad pressure wave. Lotsa blackened pipes, paint, etc. but no real damage. A giant OOPSIE in the testing.

    As for the fires afterward, the pressure wave probably tipped over a few AGE (Aerospace Ground Equipment) that had gas or diesel engines, and the LOX may have started a reactive fire(s) amongst the stuff that got banged around. LOX can do that - I've been trained. No real danger, but sure got messy. Black smoke indicates petroleum products (rubber, plastics), light black smoke indicates diesel fuel.

    Thank goodness this was just a FAE, because a contained-gasses ignition would've blown the hell outta the structures and equipment due to shrapnel! THAT would be a helluva mess to clean up.

    Doubtful that the FAA cares, OSHA *might* need a report, but SpaceX was following all safety procedures and the pad was unmanned. Maybe a few birds got singed. No sea turtles were harmed. Clean up the damaged junk and move on!

  4. I wouldn't rid in his cars either.

  5. I did note from that last video on Everyday Astronaut, that SpaceX had changed the way they startup the Raptor 2s. I guess this incident is a little insight into that process from them trying to do the spin start test on all 33 simultaneously. Hopefully there won't be a big bang when they actually start all the engines for test or launch.

    1. To me, this opens the possibility that the explosion might have just been the methane used to spin up all 33 Raptors lit up all 33 Raptors.

      An unintended static firing. For some brief, glorious, number of milliseconds, it was the beginning of lighting up all 33 engines like we'll get for the real orbital flight, surprising everyone involved.