SpaceX has revealed the cause of Starship anomalies that were responsible for delays from the FAA

Three months after the preliminary launch of the Starship carrier rocket, which ended in loss during the final phase of the carrier rocket and booster, the Federal Aviation Administration (FAA) completed the investigation.

SpaceX identified and FAA accepted the main causes and 17 corrective actions documented in SpaceX's incident report. Before the next SpaceX launch, all corrective actions must be completed and FAA must obtain a license modification that addresses all safety, environmental protection, and other applicable regulatory requirements.

— said the federal agency in a statement.

SpaceX is still required to provide additional information to the FAA about responsibility for the safety of people and property on the ground before the agency completes its review of the application for the third launch of Starship. The likely timeframe for completing the regulatory process is early to mid-March, as reported by ArsTechnica.

What went wrong

SpaceX noted that the first stage of the Super Heavy rocket was nominal, all 33 Raptor engines ignited successfully. Then the carrier rocket completed a full burning cycle to achieve stage separation. At this point, the booster performed a maneuver called "hot exit", during which the Starship stage separated from the booster while some of the booster engines were still running.

The next step for the Super Heavy was to perform a series of ignitions to make a soft landing in the Gulf of Mexico. During the first test, 13 rocket engines were supposed to start. However, several engines began to shut down before one engine failed, quickly leading to the rapid unplanned destruction of the carrier rocket.

Subsequently, the problem was linked to an issue with supplying liquid oxygen to the Raptor engines. The most likely root cause of the booster's Rapid Unscheduled Disassembly (RUD) was found to be a filter blockage through which liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in the oxidizer turbopumps of the engines, ultimately resulting in the failure of one engine and the loss of the spacecraft.

Starship ventilation holes

The spacecraft was supposed to fly almost two-thirds of the way around the Earth before falling near the Hawaiian Islands. However, about seven minutes after takeoff, there was a large release of liquid oxygen. According to SpaceX, there was an excess of liquid oxygen on board to collect data needed for future payload deployment missions. It needed to be released before the Starship fell.

A leak in the aft part of the spacecraft, caused by the launch of the liquid oxygen vent, led to a fire and subsequent fires, resulting in the loss of communication between the spacecraft's onboard computers and the command shutdown of all six engines until the end of the burn on ascent, after which the flight safety system detected a rule violation and activated the flight termination system, leading to the breakup of the spacecraft.

— stated the company.

By that time, the spacecraft had reached an altitude of 150 km and was traveling at a speed of about 24,000 km/h. This is slightly below orbital speed, which is 28,000 km/h.

In its statement, SpaceX reported that it is making changes to the Super Heavy and Starship stages to address these issues. The company is also looking to improve the overall performance of Starship by adding a new thrust vector control electronic system for the Raptor engines of the upper stage of Starship and a faster fuel loading system before launch.

SpaceX has four Starship spacecraft in the final or near-final stages of construction. If the next flight goes smoothly, the company may start launching the world's largest rocket more frequently.