WASHINGTON - The National Aeronautics and Space Administration (NASA) and Boeing are planning an uncrewed Starliner mission to the International Space Station to evaluate spacecraft modifications made after the vehicle's 2024 Crew Flight Test, with NASA targeting a return to crewed Starliner flights by 2028.
The Starliner-1 mission could launch in December 2026 or January 2027. NASA plans to use the flight to validate spacecraft modifications, evaluate its improved thermal environment, obtain propulsion-system performance data needed for qualification, and identify residual risks before crewed missions.
A primary focus is Starliner's service-module reaction-control system. NASA's investigation into the 2024 Crew Flight Test found that the service-module reaction-control thrusters operated outside their engineering qualification. Ground testing and analysis determined that the thruster performance issues resulted from a combination of factors, including the thermal environment and features inherent in the system's design.
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Modifications made
Boeing has made thermal modifications to the service module that NASA will evaluate during Starliner-1. NASA and Boeing also plan an additional modification to the service-module thruster-valve design as part of the spacecraft's certification for future crewed missions.
Following Starliner-1, NASA and Boeing plan to complete the valve modification, which is focused on addressing poppet-seal extrusion and its adverse effects on thruster performance. Boeing also plans to install new crew-module thrusters and batteries and make minor parachute system modifications to improve performance and reliability.
NASA's Program Investigation Team, which examined the 2024 Crew Flight Test, identified 61 recommendations addressing mission-related issues. NASA released the team's findings in February and is incorporating the recommendations and associated corrective actions into the Starliner return-to-flight effort.
NASA currently plans to return astronauts aboard Starliner-2 by 2028, after completing the additional testing and certification required for crewed flight.
Related: NASA, Boeing address findings from Starliner crewed flight test investigation
The agency also intends to exercise options for a fifth and sixth Starliner flight to and from the space station. In addition, NASA will work with Boeing and United Launch Alliance to certify ULA's Vulcan rocket for Starliner crew transportation after the final Atlas V flight.
NASA says the commercial crew effort is intended to maintain U.S. crew transportation capability to low Earth orbit as the agency prepares for the eventual transition from the International Space Station to commercial space stations.
