SpaceX’s second full test flight of its futuristic, bullet-shaped Starship ended in another fiery crash landing Tuesday.

Elon Musk’s company launched its latest Starship prototype from the southeastern tip of Texas, two months after the previous test ended in an equally explosive belly flop.

Later Tuesday the Federal Aviation Administration, which regulates rocket launches, announced that it will oversee an investigation of why the prototype crashed, according to The New York Times.

“Although this was an uncrewed test flight, the investigation will identify the root cause of today’s mishap and possible opportunities to further enhance safety as the program develops,” an agency spokesman said in a statement.

SpaceX at least had the permission of the FAA which disclosedthat the December launch had occurred without the agency’s approval.

“SpaceX had requested a waiver to conduct that flight even though it had not shown that a pressure wave that could be generated by an explosion during the test would not pose a danger to the public. The FAA denied the request. SpaceX defied the ruling and launched anyway,” The Times reported.

On Tuesday the full-scale stainless steel rocket reached its intended altitude of 6.2 miles (10 kilometers), slightly lower than the last one. Everything seemed to be going well as the 160-foot (50-meter) Starship flipped on its side and began its descent. But it did not manage to straighten itself back up in time for a landing and slammed into the ground.

“We’ve just got to work on that landing a little bit,” said SpaceX launch commentator John Insprucker. “Reminder — this is a test flight.”

The next Starship stood nearby at the launch site in Boca Chica, Texas, during Tuesday’s test, which lasted 6 1/2 minutes.

Musk is developing Starship to carry people to Mars, perhaps in as little as several years. It’s the upper stage of his intended moon- and Mars-ships, meant to launch atop a mega rocket called Super Heavy that is still being developed.

SpaceX tried to launch Starship last week, but failed to get the necessary approval from the Federal Aviation Administration, prompting a Twitter outburst from Musk.

SpaceX did not comply with safety regulations for the Dec. 9 flight, an FAA spokesperson said Tuesday, and needed to take corrective action before proceeding with launch operations. Tuesday’s flight met all safety criteria, according to the FAA.