Why SpaceX Didn’t Catch Starship’s Flight 15 Booster

Elon Musk says the Super Heavy booster used on Starship Flight 15 was slightly low on fuel, adding a new detail after SpaceX abandoned the vehicle’s planned tower catch and diverted it to the Gulf.

“Booster was slightly low on fuel,” Musk wrote on November 14 in a reply about the diversion.

What caused the green flame?

In a more detailed explanation, Musk blamed slight engine underperformance for the fuel shortfall. He said the green flame came from copper burning as fuel ran low in the engine’s cooling circuit and the main combustion chamber became oxygen-rich.

Super Heavy is designed to land with very little propellant left, so small performance differences matter. Musk said SpaceX is improving engine performance and consistency with Raptor V3.2, alongside a software adjustment to shut down the engines about one second earlier during ascent. That would leave more propellant for the boostback and landing burns.

Musk said improved ship and booster designs are already in production or testing, and that the booster loss does not change SpaceX’s timeline for high-volume, fully reusable flights. He later noted that the explanation is preliminary, with a full telemetry review still needed.

A setback for the booster, not the end of the mission

The update follows Flight 15’s deployment of 26 Starlink satellites. The booster missed its ride home, but the mission still put those satellites into orbit.

SpaceX said on November 14 that Starship was still coasting in orbit and looking good for a return to the launch site that day. The company also said its pad and tower systems were ready for a catch. The next big moment is Starship’s own return to the tower.

SpaceX starts recovery and beach cleanup

Following the booster’s November 13 splashdown, SpaceX said recovery teams immediately secured the area. Its environmental health and safety team was also recovering debris washing ashore, the company said, alongside a commitment to protect and restore Boca Chica Beach.

SpaceX shared the recovery update as attention turned to the ship’s separate catch attempt. Bringing Starship back into the tower’s “chopsticks” would be quite a finish to the flight.

Which matters more to you on this test flight: the satellite deployment or bringing Starship back to the tower?