Another Starship prototype exploded Tuesday morning during an attempt to nail a tricky landing technique at SpaceX’s test launch facilities in Texas. The landing attempt followed a clean liftoff and a demonstration of the rocket’s autonomous in-flight maneuvers, marking SpaceX’s fourth high-altitude flight since December.

The SN11 rocket launched at 9AM ET in foggy weather at SpaceX’s Boca Chica, Texas facilities, soaring roughly 6.2 miles to test the rocket’s three Raptor engines and a number of in-flight maneuvers that steer it back to land. As SN11 neared peak altitude, the engines gradually shut down to begin its free fall back toward the ground before executing a “landing burn” — when one Raptor reignites to carry the rocket gently down to a landing pad not far from where it launched. At least, that’s the idea.

“Something significant happened shortly after landing burn start,” SpaceX CEO Elon Musk tweeted shortly after the explosion. “Should know what it was once we can examine the bits later today.”

A live camera feed aboard SN11, streamed by SpaceX, froze moments before its landing attempt. Another feed, provided by the website NASA Spaceflight, showed large chunks of debris raining on SpaceX’s Boca Chica facilities, though the landing explosion itself was obscured by fog.

“Looks like we had another exciting test,” SpaceX’s John Insprucker said on SpaceX’s live stream, suggesting the vehicle was lost in another eventful landing attempt. “We do appear to have lost all the data from the vehicle, and the team of course is away from the landing pad.”

“At least the crater is in the right place!,” Musk tweeted. One of SN11’s engines “had issues” during ascent and didn’t fire strongly enough during the landing burn, he said.

While the fog ruined views of SN11’s landing attempt, a weather radar from the National Weather Service in Brownsville, Texas detected a plume of gas that indicated an explosion in midair.

The Federal Aviation Administration will oversee SpaceX’s investigation into the cause of SN11’s landing sequence explosion, it said in a statement Tuesday afternoon, adding that there were no immediate reports of injuries or public property damage. “The vehicle experienced an anomaly during the landing phase of the flight resulting in loss of the vehicle,” the agency said.

Spectators about five miles from SN11’s launch site said they saw what looked like Starship debris falling from the sky after SN11’s explosion. The FAA, responding to questions about the debris reports, said it “is working with SpaceX to identify whether reports of light debris in the area is related to the mishap or other phases of the flight.”

Starship is SpaceX’s next-generation, fully reusable rocket system designed to ferry humans and up to 100 tons of cargo to the Moon and Mars. The 16-story-tall prototypes SpaceX has been building and launching at a rapid pace represent only the top half of Starship — the bottom half will be a towering super-heavy booster that will help launch Starship’s top half off Earth before returning back to land.

SpaceX aimed to launch SN11 last week but held off for some additional inspections. “Standing down SN11 until probably Monday,” Musk tweeted. “Additional checkouts are needed. Doing our best to land & fully recover.” Then, on Monday, Musk said the launch would be pushed to Tuesday because an “FAA inspector unable to reach Starbase in time for launch today.”

SpaceX on Friday told the inspector, who had been in Texas all week waiting for SN11’s launch, that it wasn’t launching on Monday, so the inspector flew home, according to a person familiar with the matter. SpaceX changed plans on Sunday, telling the FAA it again aimed to launch on Monday, but by that time the inspector was home in Florida.

The inspector caught a flight and arrived back in Texas on Monday, said the person, speaking under anonymity to discuss private matters. In a statement, an FAA spokesperson said “SpaceX must provide adequate notice of its launch schedule to allow for a FAA safety inspector to travel to Boca Chica.”

The FAA required an agency inspector to be on-site for Starship tests after SpaceX violated its SN8 launch license in December, as first reported by The Verge. The violation centered on SpaceX’s decision to launch without an FAA waiver that would have permitted it “to exceed the maximum public risk allowed by federal safety regulations” in the event of a landing explosion. (SN8 launched and exploded on landing, though no one was injured.)

Update 6:30PM ET, March 30th: Adds a statement from the FAA and details about reports of debris from SN11’s test flight.