The Boeing Starliner was scheduled to launch on June 5 and fly for 10 days, but NASA has announced that its first astronaut mission will be extended into the summer.
Starliner experienced both a helium leak and a thruster problem while docking with the International Space Station (ISS) on June 6. Boeing and NASA leaders have stressed that the spacecraft is stable and could leave the ISS in an emergency, but NASA and Boeing said they want more time to determine the root cause after testing the thrusters in space.
Steve Stich, NASA’s commercial crew program manager, said in a livestreamed update with reporters today (June 28) that a test campaign to replicate how the thrusters were used during flight will begin as early as July 2 at White Sands Test Facility in New Mexico. The tests will take about two weeks, but that depends on what they find, and will require further analysis after that. That’s why NASA and Boeing have not yet set a landing date for Starliner.
“We’re not going to put a specific date on it until we’ve completed the testing, we’ve looked at the failure path and we know what that path is,” Stich said.
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Starliner’s 10-day crewed flight test mission includes NASA astronauts Butch Wilmore and Suni Williams, former U.S. Navy test pilots, and is a developmental mission with flexibility built into it in case something unexpected happens in space.
On June 6, an unexpected incident occurred during docking: an ongoing minor helium leak and the failure of five thrusters affected Starliner’s final approach to the ISS. NASA rejected the first docking attempt to ensure Starliner was ready for departure, but approved a second attempt to dock the spacecraft with the orbital complex.
Further testing and investigation of the helium source and five thrusters (out of 28 in the Reaction Control System) revealed that the leak had been stabilized and most of the thrusters had recovered, but NASA and Boeing decided not to use at least one of those thrusters during landing due to performance concerns.
Prior to today’s call, the last major update from Starliner officials was on June 21, suggesting that landing would occur no later than July 2. Participants in the call said analysis is still ongoing and further testing of the spacecraft may be necessary depending on what is found at White Sands.
“Once that’s all completed, we’ll meet and make sure we’ve done everything we need to do to understand the system and get back to you safely,” said Mark Nappi, vice president and program manager for Boeing’s Commercial Crew Programs. Nappi stressed that it’s still not clear what happens next. “These tests are unpredictable. [as to] How long will it take and how successful will it be?”
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While analysis continues on the ground, Wilmore and Williams split their time between maintenance and other duties on the ISS. “They knew this was a test flight and we were going to learn. This is all a good thing. It’s not unexpected,” Nappi said of the crew’s comments in recent communications with Boeing from orbit.
Starliner is a new type of spacecraft for Boeing, in contrast to the other private spacecraft supplier that will transport astronauts to the ISS, SpaceX’s Crew Dragon, which is based on the Cargo Dragon design. Starliner has conducted two unmanned missions to prepare for the CFT after its first attempt to reach the ISS failed in 2019 due to a computer malfunction.
Meanwhile, Dragon will conduct one uncrewed mission in 2019 and one flight test with astronauts on board in 2020, before beginning to operate crewed missions to the ISS every six months thereafter.
After the COVID-19 pandemic and dozens of revisions, Starliner’s second unmanned test flight arrived safely at the ISS in 2022, despite experiencing thruster issues during docking. One of the reasons the CFT took extra time to dock is to evaluate the Service Module, which houses most of the fuel that will be discarded during landing. This test may shed more light on why Starliner’s thruster systems experienced issues during docking in 2022 and 2024.