On Friday, SpaceX prepared its latest iteration of the Starship prototype vehicle, known as Serial No. 4, or SN4, for a static fire test in Texas. The Raptor engine appeared to fire nominally for a couple of seconds at 1:47pm local time and then shut down as planned.

However, about one minute after engine shutdown there was some kind of uncontrolled gaseous leak, and one minute later the vehicle exploded almost instantaneously—a truly rapid Rapid Unscheduled Disassembly.

The Starship prototype, fueled with liquid oxygen and methane, appeared to be mostly destroyed when the fire and smoke cleared. The test stand also sustained substantial damage. Some of the surrounding ground support equipment appeared unharmed, but it is possible the shock wave from SN4’s demise may have also damaged those structures.