SpaceX’s test vehicle, a small-scale demonstration craft for some Starship components, caught fire after what appears to be a fuel leak or dump following an otherwise successful static fire test last night. It’s not clear why the craft suddenly burst into flames, or whether it was seriously or even superficially damaged.

The “Starhopper,” as SpaceX has been calling it, is a much smaller-scale version of the Starship craft the company has in development, meant to test them out in a live-fire environment and even perform short flights called hops — hence the name. It’s being assembled and operated at SpaceX’s facilities in Boca Chica, Texas.

The big shiny craft looks a bit like a toy, but it’s a functioning rocket and it was planned that this week it would do an untethered hovering flight at some 20 meters, a step above the short tethered flights it has already accomplished. But last night’s test firing of the engines seems to have produced an anomaly.

As captured by several in the SpaceX community, the static fire started and stopped, but flames continued to burn around the base of the engines. A stream of liquid (very likely water) is directed toward it, at which point the whole rocket appears to ignite in an impressive fireball — then does it again a few seconds later. You can see the whole process (in 4K no less) in Everyday Astronaut’s video:

It’s unclear at this point what the cause of the fireball was, and whether it was in any part intentional. What’s certain is that this is not how previous test fires have gone, and generally speaking you don’t want your rocket to be on fire, even if it is highly heat-resistant.

Some have speculated that there was a fuel dump following the tests that produced lighter-than-air vapors, which rose and surrounded the rocket. The water jet may have caused the small fire to ignite the vapor, producing the fireball. I’ve asked SpaceX for any information they can share.

Images taken the next day don’t show a molten pile of slag, and in fact the vehicle doesn’t look any worse for wear on the outside. But while that’s testament to the test vehicle’s durability and stainless steel skin, it doesn’t mean there’s nothing wrong inside.

Anything unexpected happening during a test like this is reason to abort and reassess, so it won’t be a surprise if we hear that Starhopper tests have been indefinitely delayed. LabPadre, who took another video of the event, noted on Twitter that the local authorities told him SpaceX withdrew all road and beach closures, so testing is apparently off for now.

I’ll update this story if and when SpaceX provides further information on the event.