Butch Wilmore and Suni Williams have been aboard the ISS for more than 60 days as Boeing and NASA conducted extensive testing on an identical capsule at the White Sands Test Facility in New Mexico to determine the cause of Starliner’s failing thrusters.
One plan NASA is considering, the agency said on Aug. 7, is to bring Wilmore and Williams back on SpaceX’s Crew-9 mission in February 2025, which would leave the two astronauts aboard the ISS for another six months.
NASA previously planned to launch Crew-9 to the space station in September.
Steve Stitch, manager for NASA’s Commercial Crew Program, told reporters on Aug. 7 that NASA and Boeing will “use the right option at the right time” but they have yet to make a final decision.
He added that a decision will be made “likely in the middle of August.”
Starliner faced mechanical and technical issues before and after its launch on June 5.
Leaks in the helium-based propulsion system delayed the original launch by more than a month, and persisting leaks after liftoff led to multiple thrusters failing before the crew docked with the ISS on June 6.
NASA and Boeing believe the leaks are caused by a faulty rubber seal in the helium tanks.
Ground crews are working to find the safest return path for Williams and Wilmore.
Stitch said that after further helium leaks led to multiple thrusters failing during orbit, NASA and Boeing were worried about the potential risks of trying to return the crew aboard Starliner.
Stitch said the concern isn’t so much about the propulsion system combusting during reentry, it was more a question of: Would “the thrusters fail off during the deorbit burn or some other time?”
Thrusters are used for steering the spacecraft in orbit and during its landing sequence.
The flight is Starliner’s first crewed test mission and is crucial to winning approval from NASA for future space travel to succeed the retired Space Shuttle program.
If Starliner succeeds, Boeing will join SpaceX in sending astronauts to space in future missions.
SpaceX has successfully sent crew members to the space station aboard its Dragon capsule since 2020.
Boeing and SpaceX received $4.2 billion and $2.6 billion, respectively, to develop replacement spacecraft for NASA’s Space Shuttles.
Boeing was previously behind its schedule for Starliner after the first non-crewed flight in 2019 failed to reach the ISS. A subsequent flight in 2022 successfully reached the space station.
Investments into Starliner have reached more than $1.6 billion for Boeing since 2016, in addition to the grants from NASA.