The first mission of astronauts aboard the Boeing Starliner is grounded indefinitely.
The Starliner will not take off on Saturday (May 25) as planned, which was the latest launch date after several delays in recent weeks. NASA officials announced the delay on Tuesday (May 21), with no specific cause yet. But the team has been investigating a small helium leak in the Starliner’s thruster in recent weeks.
“The team has been in meetings for two consecutive days assessing flight justification, system performance and redundancy. These areas are still being worked on and other possible launch opportunities are still being discussed,” the email update said. part.
The Starliner’s Crew Flight Test (CFT) mission to the International Space Station, or ISS, as NASA and Boeing officials repeatedly emphasize, is developmental. In past briefings, officials say they always put safety ahead of schedules. NASA CFT astronauts Butch Wilmore and Suni Williams, both former US Navy test pilots, said much the same thing.
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The Starliner appeared ready for flight on May 6, but the countdown was stopped just two hours before liftoff while Wilmore and Williams were strapped to the spacecraft. (Helium leakage also occurred during this time, but at the time engineers did not consider it a problem for launch.)
The delay was eventually lifted after United Launch Alliance (ULA) discovered a problem with the oxygen relief valve on the Atlas V rocket that was to launch the duo from the Cape Canaveral Space Force Station near Orlando, Florida. The Atlas V has flown missions since 2002 with a 100% launch success rate, but the CFT will be the rocket’s first manned launch.
ULA decided that a safer option would be to address the “buzzing” valve — it opened and closed rapidly — without astronauts on board. After several hours of evaluation, the team decided to pull the stacked rocket back into shelter and replace the valve.
While at the ULA facility, the team thoroughly investigated the helium leak and announced delays, first to May 21 and then to May 25. flange on a single nozzle of the reaction control system,” NASA officials wrote in a previous update.
Helium is a non-flammable gas and poses no risk to ground operations, but proper pressure is required to send propellant to the Starliner’s dozens of engines. This helium leak was found in a part of the spacecraft used for small orbital maneuvers, according to multiple media reports.
The Starliner is only authorized to dock at one port of the Harmony ISS module on this test mission, meaning NASA must keep that slot open for the CFT launch. If the repair takes several weeks, it may be difficult for NASA to keep the site open because the ISS hosts other missions with cargo and astronauts. This is probably one of the factors behind the uncertainty of the launch date.
Williams and Wilmore remained in quarantine despite the launch delay and flew back to NASA’s Johnson Space Center in Houston in mid-May. NASA has not said whether the astronauts will emerge from their quarters, but if the delay lasts many weeks, it is likely that they will leave to focus on other CFT training duties.
New space programs often experience development delays. Boeing and SpaceX were commissioned by NASA in 2014 to send astronauts to the ISS using commercial crew vehicles. The target date for astronaut flights at that time was 2017.
Borrowing from its cargo dragon, which began flying in 2012, SpaceX successfully flew its first Crew Dragon with astronauts in 2020. The Starliner has been waiting much longer.
Starliner failed to reach the ISS during its first unmanned test flight in 2019 due to a software glitch that stuck the spacecraft in the wrong orbit. A follow-up flight got there safely in 2022 after dozens of issues were resolved, in addition to further delays due in part to the outbreak of the coronavirus pandemic in March 2020.
CFT was further delayed in 2023 after the team discovered that the capsule’s parachutes could carry less load than expected and discovered flammable tape covering much of the wiring in the spacecraft. But those issues are behind the team, NASA and Boeing officials said in the spring.