SpaceX explains reasoning for Starship 7 upper stage loss
SpaceX is set to launch its eighth test flight of the Starship rocket this Friday. Ahead of the most recent test in what could be the most revolutionary spaceflight program since NASA’s Apollo, SpaceX is clearing the air about what went wrong during its previous test flight, which resulted in the loss of the second stage during its ascension.
On January 16, SpaceX successfully launched Starship while also completing its second successful catch of the lower-stage booster.
However, the flight did not go as smoothly as initially anticipated, as the company lost Starship’s upper stage roughly eight minutes and twenty seconds into flight.
Now, the company is clarifying what happened that led to the demise of the upper stage, which SpaceX has identified with the recognition of “flashes” that occurred after vehicle separation.
SpaceX completes second catch of lower stage, but loses Starship
SpaceX says that a flash was observed roughly two minutes into its burn after vehicle separation. The flash, along with sensors that was a pressure rise in the attic, indicated a leak:
“Approximately two minutes into its burn, a flash was observed in the aft section of the vehicle near one of the Raptor vacuum engines. This aft section, commonly referred to as the attic, is an unpressurized area between the bottom of the liquid oxygen tank and the aft heatshield. Sensors in the attic detected a pressure rise indicative of a leak after the flash was seen.”
This was not the only flash that was observed. Two minutes after the first, another flash was seen, but this one was followed by sustained fires in the attic. These fires caused Starship’s engines to perform a controlled shutdown:
“These eventually caused all but one of Starship’s engines to execute controlled shut down sequences and ultimately led to a loss of communication with the ship. Telemetry from the vehicle was last received just over eight minutes and 20 seconds into flight.”
SpaceX clarified that Starship was destroyed and communication with the ship was lost before it was able to initiate any destruct rules for its Autonomous Flight Safety System. The company said this was “fully healthy when communication was lost.”
It went on to say that the “most probable root cause” of the loss was likely due to an environment not seen during testing:
“The most probable root cause for the loss of ship was identified as a harmonic response several times stronger in flight than had been seen during testing, which led to increased stress on hardware in the propulsion system. The subsequent propellant leaks exceeded the venting capability of the ship’s attic area and resulted in sustained fires.”
Nevertheless, Starship will launch for the eighth time soon, with CEO Elon Musk noting that the most likely date will be Friday. This could be the second of potentially 25 Starship launches planned for 2025.
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