Falcon 9 suffers upper stage engine failure

TOKYO — The engine on the upper stage of a SpaceX Falcon 9 malfunctioned during a launch July 11, causing the potential loss of a batch of Starlink satellites and creating repercussions across the space industry.

The Falcon 9 lifted off from Vandenberg Space Force Base in California at 10:35 p.m. Eastern. The rocket was carrying 20 Starlink satellites, 13 of which with direct-to-cell payloads, on a mission designated Group 9-3 by SpaceX.

The rocket’s ascent to orbit appeared to go as planned, with the first stage making a typical droneship landing. However, during the first burn of the second stage, observers noted an unusual buildup of ice on the cover around the Merlin engine. That buildup, not seen on typical Falcon 9 launches, did not appear to affect the stage’s performance.

The stage was scheduled to perform a one-second burn of the engine 52 minutes and 20 seconds after liftoff to circularize the orbit, followed by the deployment of the Starlink satellites. SpaceX, which ended its launch webcast by this point, did not immediately confirm either milestone.

“Upper stage restart to raise perigee resulted in an engine RUD for reasons currently unknown,” Elon Musk, chief executive of SpaceX, posted on social media two hours after liftoff. “RUD” is SpaceX jargon for “rapid unscheduled disassembly,” or an explosion.

“Starlink satellites were deployed, but the perigee may be too low for them to raise orbit. Will know more in a few hours,” Musk added.

Jonathan McDowell, an astronomer and spaceflight expert, estimated that the launch placed the upper stage on an initial transfer orbit of 138 by 295 kilometers before the second, circularization burn. When the engine anomaly took place during that brief burn will determine the perigee of the satellites and thus if they are able to avoid an immediate reentry.

The incident is the first failure, partial or total, for a Falcon since a September 2016 pad explosion during a pre-flight test, destroying the rocket and its communications satellite payload. The last in-flight failure of a Falcon 9 was in June 2015, when the upper stage broke apart during the launch of a cargo Dragon spacecraft.

Falcon 9 has built up an impressive record of success since then. This was the 354^th launch of a Falcon 9; the June 2015 in-flight failure was on the 19^th Falcon 9 launch. There have also been 10 Falcon Heavy launches, all successful, during that time.

The global space industry has become increasingly reliant on the Falcon 9 for space access given its high flight rate and issues with the development of new launch vehicles. A wide range of countries and companies have turned to the Falcon 9 for launching spacecraft. That includes companies that compete with SpaceX’s Starlink constellation and European government organizations.

The anomaly also has implications for human spaceflight. The Falcon 9 was scheduled to launch a Crew Dragon spacecraft at the end of July on the Polaris Dawn private astronaut mission, followed in mid-August by another Crew Dragon on the Crew-9 mission to deliver four astronauts to the International Space Station for a six-month mission. NASA has relied on SpaceX for accessing the ISS given delays and problems with the development of Boeing’s CST-100 Starliner spacecraft.