Boeing’s Starliner spacecraft that launched NASA’s Crew Flight Test astronauts Butch Wilmore and Suni Williams to the International Space Station is pictured docked to the Harmony module’s forward port. This view is from a window on the SpaceX Dragon Endeavour spacecraft docked to the port adjacent to the Starliner. Credit: NASA

NASA and Boeing are assessing the Starliner’s propulsion system and have completed ground tests, including a reaction control system thruster test at White Sands, revealing degraded performance.

Further docked hot fire tests are planned to check thruster and helium leaks. An agency-level review will follow to finalize the return plan, with a televised briefing expected.

Starliner Crew Flight Test Update

NASA and Boeing leadership provided an update on Starliner’s Crew Flight Test during a news conference on July 25. The integrated Starliner team continues to assess the spacecraft’s propulsion system performance and complete other tasks before scheduling its undocking from the International Space Station and return to Earth. Watch the full replay of the news conference:

Engineering teams from NASA and Boeing recently wrapped up ground hot fire testing of a Starliner reaction control system thruster at the agency’s White Sands Test Facility in New Mexico. The test series involved firing the engine under conditions like those the spacecraft experienced during its approach to the space station. The tests also included various stress-case scenarios to simulate the conditions expected during Starliner’s undocking and deorbit burn, which will position the spacecraft for landing in the southwestern United States. Teams are in the process of taking apart this thruster to conduct physical inspections. Initial findings show degraded thruster performance, which aligns with what has been observed in orbit.

Preparations for Return to Earth

Additionally, NASA and Boeing conducted a second docked hot fire test over the weekend to demonstrate the spacecraft’s thruster performance. The first docked hot fire test occurred on June 15. The new test will allow checks of the helium leaks while also verifying the thrusters are operating as expected.

NASA plans to hold an agency-level readiness review no earlier than this week. Following the review, mission leadership will finalize the plan for a normal return to Earth and select a targeted undocking date for Starliner. NASA also plans to host a televised briefing with agency and Boeing leadership following the review. More news conference details will be shared when available.

Starliner launched on June 5 and docked to the ISS on June 6. It was originally planned to return to Earth on June 14. NASA astronauts Butch Wilmore and Suni Williams continue to provide additional crew time and valuable contributions aboard the space station, assisting with science investigations and helping ground teams collect critical data for post-certification, long-duration Starliner flights to the orbiting complex.