Third time in three months
This is the third time SpaceX has grounded the Falcon 9 rocket in less than three months, ending a remarkable run of flawless launches.
SpaceX’s upper stage failed during the July 11 launch of a batch of 20 Starlink Internet satellites, stranding the payloads in a lower-than-planned orbit that caused them to reenter the atmosphere and burn up. This was the first mission failure for a Falcon 9 rocket in 335 missions since 2016, a record unmatched in the history of space launch vehicles.
Engineers traced the problem to a crack in a “sense line” for a pressure sensor attached to the vehicle’s liquid oxygen system, resulting in a liquid oxygen leak that prevented the rocket from completing the second burn of its upper stage engine. While Saturday’s upper stage issue is still under investigation, it also arose on the second burn of the Merlin vacuum engine.
The sense line is redundant, so SpaceX removed the component and successfully resumed launching the Falcon 9 rocket 15 days later.
Then, on August 28, a reusable Falcon 9 booster tipped over moments after landing on a drone ship in the Atlantic Ocean. This launch with another batch of Starlink satellites was otherwise a success, but this marked the first time SpaceX lost a rocket after landing 267 boosters in a row.
After both of these flights, the Federal Aviation Administration required SpaceX to conduct an investigation into the failures. The FAA is the regulatory agency that licenses commercial launch vehicles, and its responsibility includes ensuring launch and reentry operations do not endanger the public.
The FAA allowed SpaceX to resume launches after these two incidents after determining the failures did not have an impact on public safety. After the July 11 and August 28 incidents, the FAA issued a “public safety determination” that allowed SpaceX to return to flight with the Falcon 9 rocket after 15 days and three days, respectively.
