SpaceX believes it knows what caused the explosion during the seventh test flight of the Starship spacecraft and Super Heavy rocket on January 16, 2025. A fire in the aft part of the Starship, located between the bottom of the liquid oxygen tank and the rear heat shield, caused “all but one of the Starship’s engines to perform controlled shutdown sequences,” which led to a loss of communication and, ultimately, to the spacecraft’s safety system triggering its own destruction.
The purpose of the seventh test flight was to test several upgrades that SpaceX has made to its heavy rocket system. After a successful launch and complete combustion, the Super Heavy rocket separated from the Starship and launched the booster to return to the launch pad. After landing, the Super Heavy launch vehicle was successfully intercepted in the air for the second time by the launch tower at Starbase.
The mission did not go well for Starship. Approximately two minutes after the spacecraft ignited the Raptor second stage engines after separation, a flash was observed in the aft section of Starship, known as the “loft,” after which sensors detected a pressure increase due to a leak. Two minutes after that, a second flash was observed, followed by a sustained fire in the loft section, which eventually “caused all but one of Starship’s engines to perform a controlled shutdown sequence and ultimately resulted in the loss of communication with the ship.”
Post-flight analysis showed that the Starship’s autonomous flight safety system triggered a self-destruct sequence about three minutes after the ground crew lost contact with the spacecraft. According to SpaceX, the most likely cause of the incident was vibrations, which were much stronger during the flight than during the tests. This led to an increase in the load on the propulsion system equipment and, ultimately, to a fuel leak that “exceeded the ventilation capabilities of the ship’s attic space and led to a prolonged fire.”
The explosion caused a shower of debris that looked more like a meteor shower over the Turks and Caicos Islands to several tourists who shared videos of the aftermath on social media. While SpaceX claims that all “debris fell within the pre-planned debris response area,” the U.S. Federal Aviation Administration briefly slowed and rerouted several flights in the area on January 16 as a result of the incident.
As part of the explosion investigation involving SpaceX, the FAA, NASA, the National Transportation Safety Board and the US Space Force, the company conducted a 60-second static test launch of the Starship, which will be used in the upcoming eighth flight. Based on the results of this test, SpaceX made hardware changes to the fuel supply lines, as well as adjusted the fuel temperature and thrust performance.
The company has also added additional vents and a “new purge system using nitrogen gas” to the Starship’s attic section to make this area more resistant to fuel leaks.
Currently, SpaceX plans to launch the eighth Starship test flight on February 28, 2025, but is still “working with the FAA to either complete the investigation of the incident or obtain a safety finding, and is also working on a license permit that will allow the next Starship flight.”
