NASA has adjusted its commercial crew agreement with Boeing, reducing the number of CST-100 Starliner missions to four. Notably, the first of these missions will exclusively carry cargo. According to a statement released on November 24, NASA and Boeing mutually agreed to modify the Commercial Crew Transportation Capability contract initially awarded in 2014. The original agreement stipulated six operational missions following NASA's certification of the spacecraft for astronaut transport. The revised contract now provides funding for four such missions, with options for two additional ones. The agency has not revealed whether the modification alters the contract's original value of $4.2 billion.

The initial mission, Starliner-1, now slated for launch no earlier than April 2026, will not carry a crew. Instead, it will transport "necessary cargo" to the International Space Station (ISS) and assess modifications implemented after issues encountered during the previous Crew Flight Test (CFT). Subsequent missions will carry crews, contingent upon spacecraft certification. The first crewed flight could potentially occur before the end of 2026. According to Steve Stich, NASA’s commercial crew program manager, “NASA and Boeing are continuing to rigorously test the Starliner propulsion system in preparation for two potential flights next year,” referring to thruster problems encountered during the CFT mission that ultimately led NASA to bring Starliner back uncrewed.

NASA astronauts Butch Wilmore and Sunita Williams, who traveled to the ISS on that Starliner, experienced an extension of their planned weeks-long mission to nine months due to these issues, eventually returning on a Crew Dragon. At a July briefing, Stich noted a “strong chance” that the next Starliner mission would be uncrewed, adding "I think there’s a lot of advantages, I would say, to flying a cargo flight,” such as validating in-flight modifications to the "doghouses" on Starliner that contain thrusters. NASA's safety advisors supported this approach. Charlie Precourt, a former astronaut and member of NASA’s Aerospace Safety Advisory Panel, stated at a September 19 public meeting that “NASA is headed towards an uncrewed flight for the next Starliner mission, something that the ASAP panel sees as a very logical approach given the developmental issues with the thrusters and other anomalies on the vehicle.”

The contract amendment also acknowledges the remaining duration of the ISS program. NASA has consistently expressed a preference for alternating between Starliner and Crew Dragon for crew rotation missions, limiting each vehicle to one mission per year. With the ISS scheduled for retirement in 2030, there is limited opportunity for additional Starliner missions beyond the currently contracted four, unless the Crew Dragon encounters unforeseen problems or the ISS program is extended. "This modification allows NASA and Boeing to focus on safely certifying the system in 2026, execute Starliner’s first crew rotation when ready and align our ongoing flight planning for future Starliner missions based on the station’s operational needs through 2030,” Stich concluded.