spaceconnect logo

Boeing Starliner launch scrubbed after valve issue

The long-awaited first crewed flight of Boeing’s CST-100 Starliner has been scrubbed hours before launch due to a problem with the oxygen relief valve.

The next attempt could occur as soon as Friday, but the blast-off depends on whether the valve, which was heard to be buzzing, can be replaced.

Boeing is hoping to become only the second private firm to launch a crew to and from the ISS, following SpaceX’s Dragon capsule.

“Standing down on tonight’s attempt to launch,” Nasa chief Bill Nelson posted on social media. “As I’ve said before, NASA’s first priority is safety. We go when we’re ready.”


The issue relates to the oxygen relief valve on the rocket’s Centaur upper stage.

United Launch Alliance CEO Tory Bruno said if the vibrations heard were a full motion of the valve, it would need replacing, which would require rolling the rocket back to its assembly building.

“The team is just not comfortable with the signatures that they’re seeing, the response out of that valve, so out of an abundance of caution, we are not going to continue with our launch operations today,” said Dillon Rice, ULA launch commentator.

The spacecraft is scheduled to dock with the ISS around a day after launch, where it will remain for a week before landing at White Sands, New Mexico.


Starliner’s first attempt at an uncrewed flight failed in 2019 due to software glitches, but it eventually docked with the ISS in May 2022.

Typically, astronauts launch to the ISS via Russia’s Soyuz spacecraft and, more recently, through SpaceX’s privately owned Dragon capsule. However, recent tensions with Russia have made the Starliner test mission even more critical.

Boeing also has a lot riding on the success of Starliner, given years of problems with its best-selling 737 MAX aircraft.

In March, Space Connect’s sister brand, Australian Aviation, reported how Boeing CEO Dave Calhoun and chairman Larry Kellner would both leave the aerospace giant by the end of the year amid a broader leadership reshuffle.

Calhoun said the Alaska Airlines Flight 1282 accident in January, where an emergency exit door plug blew off a brand-new 737 MAX 9 over Portland, was a “watershed moment” for the company.

Boeing is now facing a criminal investigation over the incident, which led to the sacking of the head of its 737 program.

Adam Thorn

Adam Thorn

Adam is a journalist who has worked for more than 40 prestigious media brands in the UK and Australia. Since 2005, his varied career has included stints as a reporter, copy editor, feature writer and editor for publications as diverse as Fleet Street newspaper The Sunday Times, fashion bible Jones, media and marketing website Mumbrella as well as lifestyle magazines such as GQ, Woman’s Weekly, Men’s Health and Loaded. He joined Momentum Media in early 2020 and currently writes for Australian Aviation and World of Aviation.

Receive the latest developments and updates on Australia’s space industry direct to your inbox. Subscribe today to Space Connect here.

Receive the latest developments and updates on Australia’s space industry direct to your inbox. Subscribe today to Space Connect.