The Booster 7 prototype did not go as planned on Monday.
At around 4:20pm local time, at the company's testing facilities near Boca Chica, Texas, the giant rocket went up in a fireball.
Chris Bergin of NASA SpaceFlight said "Holy moly". That was not what I was expecting.
At first, Musk implied that the explosion was planned, but then quickly deleted the message, explaining that it was actually an accident.
He responded to Bergin two hours after the blast. Damage is being assessed by the team.
What was the cause of the problem? The launch pad has an oxygen rich environment.
"Cryogenic fuel is an added challenge, as it evaporates to create fuel-air explosion risk in a partially oxygen atmosphere like Earth," he said.
We have a lot of sensors to detect this. It's later.
The company will set up sparks under the engine section to make sure that all leaking sources of hydrogen burn off before a huge fireball.
Musk inspected the damage hours later.
The base of the vehicle seems okay. About an hour ago, I was out there. The pads were shut down for safety. In the morning, will know more.
It's a big blow for the company. We don't know when the company's first test flight will take place.
The stakes are higher than they have been. There is a chance that the next explosion could be around the corner.
There is an explosion and a prototype of a booster goes up in flames.