SpaceX has revealed new details about the failure of its Starship vehicle during a test flight last month, attributing the loss to propellant leaks caused by an unexpectedly strong harmonic response. The company shared its findings on February 24 as it prepares for the next test flight.
Credit: SpaceX
The seventh integrated test flight of the Starship and Super Heavy system, conducted on January 16, ended when the Starship upper stage broke apart over the Caribbean. According to SpaceX, the issue arose about two minutes after stage separation, when a flash was observed in the vehicle’s aft section—known as the “attic”—near one of its six Raptor engines. Shortly after, a pressure increase suggested a propellant leak in that area.
Two minutes later, another flash was followed by sustained fires in the attic, ultimately leading to the shutdown of all but one of Starship’s engines. The company stated that communication with the vehicle was lost approximately 8 minutes and 20 seconds after liftoff. The autonomous flight termination system activated about three minutes after the loss of telemetry.
SpaceX identified the root cause as an unexpectedly strong harmonic response in flight, far exceeding what had been observed in ground testing. This resulted in increased stress on propulsion system components, leading to propellant leaks. The leaked propellant could not be properly vented, fueling the fires that ultimately led to engine shutdowns and vehicle loss.
As part of its investigation, SpaceX conducted a 60-second static fire test of the Starship vehicle intended for the next mission, Flight 8, on February 12. The test evaluated multiple engine thrust levels and different hardware configurations to replicate and address the harmonic response seen during Flight 7. Based on the results, SpaceX has implemented hardware modifications to the fuel feedlines, adjustments to propellant temperatures, and a new thrust target for the upcoming flight.
To further mitigate risks, SpaceX is introducing additional vents and a gaseous nitrogen purge system to reduce flammability in the attic section.
The company is now moving forward with Flight 8, targeting a launch as soon as February 28 from its Starbase facility in Boca Chica, Texas, pending Federal Aviation Administration (FAA) approval of the Flight 7 investigation. The upcoming mission will aim to complete objectives that were not achieved in the previous test, including deploying four mass simulators representing next-generation Starlink satellites. Starship will also test new reentry protection technologies, such as metallic tiles with active cooling.
As in the previous flight, SpaceX will attempt to “catch” the returning Super Heavy booster at the launch tower. The booster has received upgrades to avionics, power distribution systems, and Raptor engine igniters after an issue during Flight 7’s boostback burn caused one of 13 engines to shut down at ignition.
Reflecting on the test flight, SpaceX acknowledged that development is not always linear, emphasizing that real-world testing is the fastest way to refine the system. “Upcoming flights will continue to target ambitious goals in the pursuit of full and rapid reusability,” the company stated.
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