SpaceX returns to orbit just two weeks after in-flight glitch

Early Saturday morning, at 1:45 local time, the Falcon 9 rocket lifted off into orbit from its launch site at the Kennedy Space Center in Florida.

By some measures, it was a pretty routine mission — after all, it was SpaceX’s 73rd launch of the year. Like many other Falcon 9 launches this year, the Starlink 10-9 mission carried 23 broadband internet satellites into orbit. However, after a rare failure earlier this month, this Falcon 9 rocket is back in service for the company, in an attempt to restart the world’s most active rocket.

By all accounts, the rocket performed its mission successfully. The first-stage booster, B-1069, made its 17th flight into orbit before landing on Just read the instructions. Just over an hour after launch, the rocket’s second stage delivered its payload into a high-altitude orbit, where Starlink vehicles will use their onboard thrusters to reach operational altitudes in the coming weeks.

Cleft in the sense line

The Falcon 9 rocket failed a little over 15 days ago, during the Starlink launch from Vandenberg Spaceport, California, at 7:35 p.m. PDT (02:35 UTC) on July 11. During that mission, just a few minutes after the stage separated, an unusual buildup of ice was observed on the Merlin vacuum engine that powers the spacecraft’s second stage.

According to the company, the Merlin vacuum engine successfully completed its first burn after the second stage separated. However, during this time, a liquid oxygen leak occurred near the engine, which led to the ice buildup that was observed during the webcast.

Engineers and technicians were quickly able to determine the cause of the leak: a crack in the “sensing line” of the pressure sensor connected to the vehicle’s liquid oxygen system. “This line cracked due to fatigue caused by high loads caused by engine vibration and loosening of the clamp that normally holds the line,” the company said. In the update It was published ahead of its launch on Saturday morning.

This leak caused the engine to overcool, reducing the amount of spark plug fluid available before the Merlin could be re-ignited for a second burn to re-orbit the rocket before launching the Starlink satellites. This caused the Merlin engine to have a rough start. The satellites were eventually launched into a lower orbit, where they burned up in Earth’s atmosphere within days.

SpaceX said the failed sensor line is now redundant. It is not used by the flight safety system and can be covered by replacement sensors already on the engine. In the near term, the sensor line will be removed from the second-stage engine for Falcon 9 launches.

During a press conference Thursday, SpaceX director Sarah Walker said the sensor line was installed based on a customer request for another mission. The only difference between this component and other common sensor lines is that it has two connections instead of one, she said. That may have made it more susceptible to vibration, which could have led to a small crack.

Quick return

SpaceX was able to identify the cause of the failure within hours of it occurring and worked with the Federal Aviation Administration to quickly come up with a solution. On Thursday, the launch company received clearance to return to flight.

“It was amazing to see how quickly the team was able to identify the cause of the incident, and then take the corrective actions associated with it to ensure success,” Walker said.

Before the failure on the night of July 11, SpaceX had not experienced a single failure in its 297 previous Falcon 9 launches, dating back to the Amos 6 launch pad explosion in September 2016. The short time between the failure earlier this month and the return to flight on Saturday appears to be unprecedented in the history of spaceflight.

The company now plans to launch two more Starlink missions on a Falcon 9 rocket this week, one from Cape Canaveral Space Station in Florida and one from Vandenberg Space Base in California. It then has three more missions before NASA’s crucial Crew 9 astronaut launch, which could happen as soon as Aug. 18.

That’s why NASA got involved in the investigation into the second-stage failure. Steve Stich, NASA’s Commercial Crew Program manager, said SpaceX did an “exceptional job” in identifying the root cause of the failure, and then quickly inspected the Dragon and Falcon 9 first stage to make sure there were no other sensors that could cause similar problems.