NASA and Roscosmos have extended their seat barter agreement for flights to the International Space Station (ISS) into 2027. This extension includes longer Soyuz missions to the station. NASA astronaut Chris Williams has been assigned to the Soyuz MS-28 spacecraft, launching in November, alongside Roscosmos cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev. This announcement followed the April 8 launch of astronaut Jonny Kim to the ISS on Soyuz MS-27.
The agreement ensures at least one American and one Russian astronaut on the ISS, safeguarding against potential delays with either Soyuz or commercial crew vehicles. The future of this agreement was uncertain last fall when Roscosmos's initial crew assignments for Soyuz MS-28 and MS-29 included only Russian cosmonauts. NASA Administrator Bill Nelson stated then that an extension was expected “in due course.” Russian media reports in January suggested the extension was finalized, but NASA initially declined to confirm.
The extended agreement includes "a second set of integrated crew missions in 2025, one set of integrated crew missions in 2026, and a SpaceX Dragon flight in 2027," according to a NASA spokesperson. A significant change is the increased duration of Soyuz missions to eight months, from the previous six, resulting in fewer Soyuz launches. Both Kim and Williams’ missions are slated for eight-month stays. NASA's commercial crew missions will continue at roughly a six-month cadence.
The inclusion of future Boeing Starliner missions in the agreement remains uncertain. NASA officials previously indicated Roscosmos's participation in Starliner-1 was unlikely. The schedule for Starliner-1 remains fluid due to delays and investigations following the Crew Flight Test. Mike Fincke, initially assigned to Starliner-1, was recently reassigned to Crew-11.