Insider Brief
- SpaceX’s seventh Starship test flight achieved major milestones in booster reusability but was cut short due to unexpected vibrations in the propulsion system, leading to a loss of communication.
- The failure was traced to excessive harmonic oscillations, which stressed the fuel system, caused leaks, and resulted in sustained fires in an unpressurized section of the vehicle.
- SpaceX is addressing the issue by redesigning fuel lines, adjusting propellant conditioning, improving venting systems, and introducing the Raptor 3 engine to enhance future Starship flights.
With Starship 8 mission planned as early as today, SpaceX engineers are processing what went right — and what went wrong — with the vehicle’s seventh flight test.
According to a SpaceX blog post, SpaceX’s latest Starship test flight successfully demonstrated key reusability milestones but ended prematurely due to a failure linked to unexpected vibrations in the propulsion system,
The company is applying lessons from the flight to improve future Starship designs.
“Starship’s seventh flight test was a reminder that developmental progress is not always linear, and putting flight hardware in a flight environment is the fastest way to demonstrate how thousands of distinct parts come together to reach space,” the team writes. “Upcoming flights will continue to target ambitious goals in the pursuit of full and rapid reusability.”
On January 16, 2025, Starship lifted off from SpaceX’s Starbase facility in Texas at 4:37 p.m. CT, marking the seventh test of the company’s fully reusable rocket system, according to the post. The team writes that the mission had ambitious goals: successfully launching an upgraded second stage while executing a return and catch of the Super Heavy booster. While not all objectives were met, SpaceX is using the flight’s data to refine its approach as it moves toward routine Starship launches.
The Super Heavy booster completed its mission successfully. All 33 Raptor engines ignited at launch, and the booster executed a controlled descent before being caught by the launch tower’s mechanical arms — a key step toward making Starship fully reusable. However, the upper stage experienced an issue that ultimately led to a loss of communication with the vehicle, ending the mission prematurely.
What Went Wrong
The test flight’s main failure stemmed from an unexpected structural response within the Starship upper stage’s propulsion system. Two minutes after ignition of Starship’s six second-stage engines, sensors detected a leak in an unpressurized section of the vehicle, known as the attic, which houses fuel lines and other critical systems. This was followed by a second leak, leading to sustained fires that eventually shut down all but one of the second-stage engines. Communication was lost a little over eight minutes into the flight.
The most probable cause was identified as a harmonic vibration, or oscillation, that was significantly stronger than what had been observed in ground testing. The vibrations increased mechanical stress on the vehicle’s fuel system, causing propellant leaks that exceeded the ship’s venting capacity and led to ignition in the attic section. The loss of control triggered the vehicle’s automated safety system, leading to its breakup in the upper atmosphere.
Mitigation and Next Steps
SpaceX has outlined several upgrades aimed at preventing similar failures in future Starship flights. These include modifications to the fuel lines supplying the vacuum engines, adjustments to how propellant is conditioned before use, and changes to the engine’s operating thrust levels. Additionally, new venting and purge systems using gaseous nitrogen are being installed to reduce flammability risks in the attic section.
The company has also announced plans to introduce the next-generation Raptor 3 engine, which will feature a redesigned structure that reduces the size of the attic and eliminates many of the joints where fuel leaks could occur.
As part of its response, SpaceX conducted a 60-second static fire test to replicate the harmonic response seen during the flight. The test, which evaluated different engine thrust settings and fuel configurations, provided further insights that will guide hardware improvements.
Regulatory Oversight and Flight Path Adjustments
The Federal Aviation Administration (FAA) is overseeing SpaceX’s investigation, with input from NASA, the National Transportation Safety Board, and the U.S. Space Force, according to the post. The FAA will determine whether to close the mishap investigation or require further safety measures before issuing a new launch license.
Despite the in-flight failure, all debris from the breakup landed within the designated response area, and SpaceX coordinated cleanup efforts with the governments of the Turks and Caicos and the United Kingdom. The company stated that no hazardous materials were present in the debris and that no significant environmental impacts were expected.
Lessons in Rapid Development
Starship’s seventh test flight reinforced SpaceX’s philosophy that real-world testing provides the fastest route to improvement. The company has repeatedly emphasized that early failures are expected in Starship’s development, as each test flight informs the design of future vehicles.
With an eye toward rapid reusability, the company remains committed to pushing the limits of Starship’s capabilities, the team writes. Future tests will incorporate the latest upgrades while continuing to validate core functions, such as launch, stage separation and controlled return. They hope that with each iteration, SpaceX moves closer to its ultimate goal: a fully reusable rocket capable of interplanetary travel and high-frequency space launches.
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