Boeing's long-delayed Starliner crewed launch, which was scheduled for today, has been postponed yet again, this time due to a valve problem on the Centaur upper stage. Managers pushed back the next attempt to no earlier than May 10.

It is the closest Boeing has come to launching a crew in the Starliner capsule. The countdown was approaching the two-hour mark before the scrub call came in as managers worried about "anomalous behavior by the pressure regulation valve in the liquid oxygen tank of the Centaur upper stage of the ULA Atlas V launch vehicle," according to Boeing.

United Launch Alliance, responsible for the Atlas V that will launch Boeing's Starliner, said: "Out of an abundance of caution for the safety of the flight and pad crew, we scrubbed the Crew Flight Test (CFT) launch attempt today due to an observation on a liquid oxygen self-regulating solenoid relief valve on the Centaur upper stage.

"The team needs additional time to complete a full assessment, so we are targeting the next launch attempt no earlier than Friday, May 10."

The crew, consisting of Space Shuttle and International Space Station (ISS) veterans Sunita "Suni" Williams and Barry "Butch" Wilmore, had boarded the spacecraft before the scrub was called. This launch was set to be the 100th flight of the Atlas V rocket, and notably the first carrying humans.

The mission is the first crewed test flight of Boeing's Starliner to the ISS and comes several years after SpaceX first performed the feat with its Crew Dragon spacecraft. SpaceX's first crewed test flight of the Crew Dragon occurred in 2020.

It has taken nearly ten years for Boeing to reach this point. In 2014, it was awarded $4.2 billion and SpaceX $2.6 billion as NASA sought to reduce its reliance on Russia and launch its astronauts from US soil on American spacecraft. The goal was to end dependency on Russia by 2017.

At the time, the US space agency said: "NASA's expert team of engineers and spaceflight specialists is facilitating and certifying the development work of industry partners to ensure new spacecraft are safe and reliable."

The words ring hollow after Boeing's many setbacks in its attempt to send a crew to the ISS. The first test launch - without a crew - ended in near catastrophe thanks to multiple issues, including timer problems.

NASA acknowledged that maybe it should have paid closer attention to Boeing as a raft of quality and testing issues came to light.

Starliner finally made it to the ISS in 2022 in another uncrewed test dubbed Orbital Flight Test 2 (OFT-2). However, the mission was not without incidents or delays, thanks partly to valves in the Calamity Capsule failing pre-flight checks.

The latest scrub comes on the heels of yet more delays, including worries over parachute linkage points and the flammability of tape.

One day, Boeing's Starliner will carry a crew to the ISS, and we can retire the nickname "Calamity Capsule." Just not today. ®

https://www.theregister.com//2024/05/07/boeing_starliner_delay/