Elon Musk Says Methane Leak Caused Starship SN11 Explosion

SpaceX CEO Elon Musk said a methane leak caused the Starship SN11 prototype to explode in midair on March 30. Musk tweeted:

Ascent phase, transition to horizontal & control during free fall were good.

A (relatively) small CH4 leak led to fire on engine 2 & fried part of avionics, causing hard start attempting landing burn in CH4 turbopump.

This is getting fixed 6 ways to Sunday.— Elon Musk (@elonmusk) April 5, 2021

The leak and explosion occurred as the vehicle was beginning preparations to land at SpaceX’s test site at Boca Chica, Texas. It was the fourth failure to land a Starship prototype in as many attempts.

The SN15 Starship is now being prepared for flight. SpaceX elected to skip prototypes SN12 through SN14.

Starship SN11 Explodes & Crashes During Landing Maneuver

SpaceX launched its Starship SN11 prototype from Boca Chica on Tuesday morning, only to see the vehicle crash like its predecessors SN8, SN9 and SN10.

It is not entirely clear what precisely went wrong because the vehicle was launched in a thick fog that enveloped the coastal launch site in south Texas.

Using onboard cameras, SpaceX’s website showed SN11 reaching 10 km as it gradually shut off all three engines. It then glided down to an altitude of 1 km, at which time SN11 began to restart one of its engines and to pivot for a landing.

At 5:49 into the flight, the feed from the onboard camera froze. This was followed by the sound of what appeared to be an explosion and vehicle parts crashing to the ground.

“We do appear to have lost all data from the vehicle,” said John Insprucker, who anchored SpaceX’s webcast of the test. “We’re going to have to find out from the team what happened.”

Insprucker ended the webcast a short time later without providing any further details. SpaceX CEO Elon Musk tweeted, ‘At least the crater is in the right place!”

“Looks like engine 2 had issues on ascent & didn’t reach operating chamber pressure during landing burn, but, in theory, it wasn’t needed,” Musk later tweeted. “Something significant happened shortly after landing burn start. Should know what it was once we can examine the bits later today.”

The next vehicle will be called SN15. As part of SpaceX’s rapid prototyping approach, SN12 through SN14 have been skipped.