SpaceX Wraps Up Probe Into Starship Failure That Scattered Debris Over Vacation Spots

We now know the likely cause of a Starship test flight failure that caused rocket parts to rain down over popular tourist destinations back in January, and forcing airlines to divert flights.

The upper stage Starship spacecraft experienced a stronger-than-expected harmonic response, according to a statement from SpaceX. By harmonic response, engineers mean vibrations amplified by resonance. That, in turn, put increased stress on the propulsion system, likely causing the rocket to explode before it had the chance to reach space.

On January 17, the Super Heavy booster’s 33 Raptor engines all fired successfully at launch, and the booster was able to both start up and complete its full burn. The upper stage ignited its own Raptor engines as it separated from the booster. While the booster did ultimately return to the ground, where it was caught at the launch site, there was a slight hiccup to the process. A low-power condition in one engine’s igniter system forced it to prematurely shut down, but the other 12 engines worked fine. SpaceX said a potential problem of this nature had already been identified and rectified for future flights by upgrading the igniter system.

Things didn’t go as swimmingly for the Starship’s second stage. Roughly two minutes after the engine burn began, “a flash was observed in the aft section of the vehicle near one of the Raptor vacuum engines,” SpaceX explained. “This aft section, commonly referred to as the attic, is an unpressurized area between the bottom of the liquid oxygen tank and the aft heat shield. Sensors in the attic detected a pressure rise indicative of a leak after the flash was seen.”

Shortly after, another flash was seen, and fires broke out in the attic, leading to multiple engines undergoing a controlled shutdown. Communication was then lost with the ship.

“​​Contact with Starship was lost prior to triggering any destruct rules for its Autonomous Flight Safety System, which was fully healthy when communication was lost,” SpaceX said. “The vehicle was observed to break apart approximately three minutes after loss of contact during descent. Post-flight analysis indicates that the safety system did trigger autonomously, and breakup occurred within Flight Termination System expectations.”

The investigation, launched by SpaceX and overseen by the Federal Aviation Administration (FAA), was mandated by the FAA after the incident. The flight failure caused debris to rain down over the Atlantic Ocean, with some falling on inhabited portions of Turks and Caicos. No injuries were reported, though residents said they found remnants of the rocket on their properties and along local beaches.

SpaceX offered a rosier account of the aftermath, saying that all debris “came down within the pre-planned Debris Response Area, and there were no hazardous materials present in the debris and no significant impacts expected to occur to marine species or water quality.”

“While an early end to the flight test is never a desired outcome, the measures put in place ahead of launch demonstrated their ability to keep the public safe.”

Starship is a super-heavy lift launch vehicle that has a key role in NASA’s future plans. One planned variant would take astronauts to the Moon as part of the space agency’s Artemis program. Others would be capable of transporting huge amounts of cargo, such as Starlink satellites, into orbit.

The rocket’s next test launch is currently scheduled for Friday, February 28. As a result of the investigation’s findings, several modifications have been made to the design, including changes to the fuel feed lines to the vacuum engines, as well as adjustments to propellant temperatures. Vents and a purge system were also added to the attic to make it more fire resistant.

Rockets are incredibly complicated, and several of the Starship tests have ended with mishaps. The first, in April 2023, led to massive damage to the launch pad. The rocket itself blew up around four minutes into its flight. The second flight test fared better, as key milestones were met, despite both the booster and upper stage being destroyed. Subsequent test runs identified even more issues, and SpaceX has now twice executed successful catches of the booster stage as it returns to the ground. Clearly, though, there are still kinks that need to be worked out.