Starliner Crew Flight Test Extension Reflects Propulsion Risk, Not Record Attempt

September 6, 2026 at 01:30 AM2 min

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NASA extended Suni Williams and Butch Wilmore's Starliner test flight from eight days to 286 days after propulsion failures during approach to the International Space Station. The agency returned Starliner to Earth empty on 24 August 2024, reassigning the astronauts to SpaceX Crew-9. The decision reflected uncertainty in the propulsion system, not a planned long-duration mission.

Key Facts

Suni Williams and Butch Wilmore launched on Boeing Starliner's first crewed test flight on 5 June 2024 for an expected eight-day mission.
The astronauts returned on 18 March 2025 after 286 days in space aboard a SpaceX Dragon, not Starliner.
Starliner developed additional helium leaks and lost reliable thrust from five reaction-control jets during approach to the ISS.
NASA decided on 24 August 2024 to send Starliner home empty and assign Williams and Wilmore to SpaceX Crew-9.
Starliner later completed a safe autonomous descent, but that outcome was unknown when NASA made the crew return decision.

Propulsion Failure During Approach

A small helium leak was detected in one manifold of Starliner's service-module reaction-control system before launch. NASA and Boeing analyzed the leak and accepted the flight with it present. During rendezvous on 6 June, additional helium leaks appeared and five reaction-control jets lost reliable thrust. NASA and Boeing spent the summer firing thrusters, analyzing telemetry, and recreating the problem on the ground. The work established plausible failure mechanisms but did not give NASA enough confidence for a crewed return.

Decision to Return Uncrewed

On 24 August 2024, NASA decided to send Starliner home empty. Williams and Wilmore became part of the station's long-duration expedition and were assigned to SpaceX Crew-9. Starliner eventually made a safe autonomous descent, but that successful outcome did not exist when managers had to choose. A spacecraft can remain capable of landing and still carry more uncertainty than NASA is willing to accept with people aboard.