SpaceX founder Elon Musk said Monday that a “relatively small” methane leak caused the explosion of the company’s latest Starship test rocket last week on an experimental flight over South Texas.
The 164-foot-tall (50-meter) Starship test vehicle, known as Serial No. 11, took off from SpaceX’s development facility near Brownsville on March 30 for an atmospheric test flight to an altitude of about 33,000 feet, or 10,000 meters.
Three Raptor engines, each consuming super-chilled methane and liquid oxygen propellants, powered the stainless steel rocket off its launch mount with more than a million pounds of thrust.
After climbing straight up above a dense layer of fog, the Starship shut down each of the Raptor engines in sequence, as planned, before pitching over horizontally to begin a controlled descent back to the ground. Aerodynamic flaps helped stabilize the giant vehicle as it fell back to Earth before the Raptor engines were supposed to reignite and flip the rocket back vertical for touchdown on a landing pad next to the Starship’s launch site.
Dense fog prevented clear views of what happened, but an on-board camera view on SpaceX’s live webcast froze as the Raptor engines fired up for landing. Other camera views showed debris showering the test site, which Musk calls Starbase, after a thundering boom crackled across the facility.
Light debris fragments from the Starship apparently traveled as far as 5 miles (8 kilometers) from the launch site and landed in a public viewing area, although the material may have been shed from the rocket as it climbed toward the apex of its trajectory, and not during the explosion just before landing.
Musk tweeted Monday that the ascent phase of the Starship SN11 test flight went according to plan. The transition to horizontal and control during its free fall back to Earth were also good, he said.
But a small methane leak led to a fire on one of the vehicle’s Raptor engines and “fried” part of an avionics system. That caused a “hard start” in the engine’s methane turbopump at the beginning of the landing burn, Musk said.
