SpaceX's Starship SN4 launch vehicle prototype explodes after static engine fire test

Darrell Etherington

SpaceX had just conducted yet another static fire test of the Raptor engine in its Starship SN4 prototype launch vehicle on Friday when the test vehicle exploded on the test stand in Boca Chica, Texas. This was the fourth static fire test of this engine on this prototype, so it's unclear what went wrong versus other static fire attempts.

This was a test in the development of Starship, a new spacecraft that SpaceX has been developing in Boca Chica. Eventually, the company hopes to use it to replace its Falcon 9 and Falcon Heavy rocket, but Starship is still very early in its development phase, whereas those vehicles are flight-proven, multiple times over.

SpaceX had just secured FAA approval to fly its Starship prototype for short, suborbital test flights. The goal was to fly this SN4 prototype for short distances following static fire testing, but that clearly won't be possible now, as the vehicle appears to have been completely destroyed in the explosion following Friday's test, as you can see below in the stream from NASASpaceflight.com.

The explosion occurred around 1:49 PM local time in Texas, roughly two minutes after it had completed its engine test fire. We've reached out to SpaceX to find out more about the cause of today's incident, and whether anyone was hurt in the explosion. SpaceX typically takes plenty of safety precautions when running these tests, including ensuring the area is well clear of any personnel or other individuals.

This isn't the first time one of SpaceX's Starship prototypes has met a catastrophic end; a couple of previous test vehicles succumbed to pressure testing while being put through their paces. This is why space companies test frequently and stress test vehicles during development -- to ensure that the final operational vehicles are incredibly safe and reliable when they need to be.

SpaceX is already working on additional prototypes, including assembling SN5 nearby in Boca Chica, so it's likely to resume its testing program quickly once it can clear the test stand and move in the newest prototype. This is a completely separate endeavor from SpaceX's work on the Commercial Crew program, so that historic first test launch with astronauts on board should proceed either Saturday or Sunday as planned, depending on weather.