On July 11, when a Falcon 9 was launching 20 of SpaceX’s Starlink broadband satellites into low Earth orbit, the failure took place. The rocket’s first stage ran smoothly that day, but an oxygen leak in its upper stage stopped it from performing the intended orbit-raising burn. As a result, the Starlink satellites were launched too low and quickly returned to Earth, where they burned up in the planet’s dense atmosphere.
The enigma surrounding the leak’s origin is now solved. In an update on Thursday afternoon (July 25), SpaceX stated that it was caused by “a crack in a sense line for a pressure sensor attached to the vehicle’s oxygen system.” “This line cracked due to fatigue caused by high loading from engine vibration and looseness in the clamp that normally constrains the line.”
On July 11, the upper stage’s lone Merlin engine executed its first burn according to plan, precisely as it entered a coast phase in an elliptical orbit. However, according to SpaceX’s anomaly study, which was supervised by the US Federal Aviation Administration (FAA), the leak stopped the engine from performing a second burn, which was intended to circularize its orbit prior to Starlink satellite placement.
In an update published on Thursday, the business stated that the leak “led to the excessive cooling of engine components, most importantly those associated with the delivery of ignition fluid to the engine.” “As a result, the engine experienced a hard start rather than a controlled burn, which damaged the engine hardware and caused the upper stage to subsequently lose attitude control.”
All 20 satellites were successfully launched by the upper stage, but as was already said, their orbital lifetime was short.
The update stated that “the failed sense line and sensor on the second-stage engine will be removed for near-term Falcon launches,” according to company reps.
“The sensor is not used by the flight safety system and can be covered by alternate sensors already present on the engine,” they stated.”The design change has been tested at SpaceX’s rocket development facility in McGregor, Texas, with enhanced qualification analysis and oversight by the FAA and involvement from the SpaceX investigation team. An additional qualification review, inspection, and scrub of all sense lines and clamps on the active booster fleet led to a proactive replacement in select locations.”
The FAA has received SpaceX’s accident report. Thursday afternoon, the firm announced on X that it is “poised to rapidly return to flight as soon as Saturday, July 27.”
Since a Falcon 9 rocket disintegrated in June 2015 while delivering a robotic Dragon cargo capsule toward the International Space Station, SpaceX has not experienced an in-flight malfunction until the anomaly of July 11. The Dragon was lost as a result of the mishap.
Nevertheless, in September 2016, during preflight testing, a Falcon 9 exploded on the pad. The AMOS-6 communications satellite, which was part of the rocket’s payload, was also lost due to that incident.