SpaceX’s recent Starship test flight, the first during which it flew with its Super Heavy orbital booster, was a bit more of a mess than it even appeared when it ended with a large explosion. During a Twitter Space on Saturday, SpaceX founder and Twitter owner Elon Musk shared more details about the launch, which he still characterized as “successful” relative to SpaceX’s aims with the mission.

During the launch, it was obvious things weren’t going exactly to plan when, at the point during the flight when the first-stage booster was supposed to separate from the Starship upper stage, the two pieces did not come apart — and instead the entire launch vehicle appeared to start falling back to Earth while spiraling wildly.

Starship is equipped with an automated self-destruct feature that’s designed to reduce the risk of an out-of-control return to Earth for the massive spacecraft. Musk revealed that the command didn’t work immediately in this most recent flight attempt, with 40 seconds passing instead before it actually resulted in an explosion that destroyed the bulk of the rocket.

Musk also revealed additional details about what went wrong with the flight, including the fact that three of the rocket’s 33 total engines didn’t even participate in the launch thrust, having shut down before Starship left the pad. That resulted in a “lean” as the spacecraft ascended, which is not intended behavior.

Finally, just under 30 seconds into the launch, one of the remaining Raptor 2 engines had a fault that also damaged other engines near it. At about a minute and a half in, the engines lost their ability to control the direction of the launch vehicle, which is why that spinning occurred.

The original take-off also included unplanned events, like the massive cloud of dust and debris generated by the destruction of the concrete launch pad that resulted from the lift-off thrust. This sent debris hurtling around the launch facility surroundings — and new satellite images show some of the impact of the event.