Roscosmos To Reduce Launches To ISS; NASA Crew Exchange Agreement Extended Through 2027

NASA and the Russia Space Agency, Roscosmos, have officially extended their seat barter agreement for crew flights to the International Space Station (ISS) through 2027, ensuring continued collaboration aboard the orbital outpost and introducing a new shift in Soyuz mission durations.

The extension, quietly formalized earlier this year, was publicly confirmed following NASA’s April 3 announcement that astronaut Chris Williams has been assigned to fly aboard the upcoming Soyuz MS-28 mission, slated to launch in November 2025. Williams will join Russian cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev for an extended stay of eight months on the ISS.

This assignment follows the successful April 8th launch, of NASA astronaut Jonny Kim on Soyuz MS-27, which will be docked to the ISS also for an eight-month stint, and marks the continuation of the longstanding barter-based arrangement that began in 2022.

Under the agreement, NASA astronauts fly aboard Russian Soyuz spacecraft, while Roscosmos cosmonauts fly aboard American commercial crew vehicles such as SpaceX's Crew Dragon. The goal: to ensure uninterrupted joint operations aboard the ISS in case one transportation system is grounded.

A Strategic Redundancy

Former NASA Administrator Bill Nelson had previously signaled his expectation that the agreement would be extended, but details remained elusive. Although Russian media hinted in January that the deal had been renewed, NASA did not officially confirm it until this month.

“NASA and Roscosmos have amended the integrated crew agreement to allow for a second set of integrated crew missions in 2025, one set of integrated crew missions in 2026, and a SpaceX Dragon flight in 2027” - NASA Spokesperson

As before, the agreement remains a no-exchange-of-funds arrangement, a practical compromise to ensure both nations retain continuous presence aboard the ISS, a critical safety and operational measure should one vehicle type become unavailable.

Longer Soyuz Stays, Fewer Flights

A notable change in the updated agreement is the shift in Soyuz mission duration. While Soyuz flights had traditionally lasted about six months, the latest missions, beginning with MS-27, will now remain docked to the ISS for approximately eight months.

NASA’s announcements for both Kim and Williams confirm the extended duration. Neither agency has disclosed an official reason for the change, but the implications are clear: Roscosmos will reduce its launch cadence, flying three Soyuz missions over the next two years instead of four.

This adjustment may help Roscosmos conserve resources while maintaining its operational role on the ISS. Meanwhile, NASA is continuing its roughly six-month cadence for SpaceX Crew Dragon missions, although schedules vary based on visiting vehicle traffic and operational constraints.

Starliner Still in Limbo

The extension also raises questions about future crew assignments aboard Boeing’s long-delayed Starliner spacecraft. While Roscosmos cosmonauts have flown on Crew Dragon since 2022, they have yet to commit to flying aboard Starliner.

NASA officials previously stated it was unlikely that a Russian cosmonaut would fly on the first operational Starliner rotation, Starliner-1; echoing the caution Roscosmos showed before adopting Crew Dragon. The first crewed Starliner test flight (CFT) has faced repeated delays and is still awaiting completion before operational missions can proceed.

In a recent crew shuffle, astronaut Mike Fincke, one of the originally assigned members of Starliner-1, was reassigned to SpaceX’s Crew-11 mission, currently scheduled to launch as soon as July. This move highlights the uncertain timeline for Starliner’s future in the ISS crew rotation mix.

Continued Cooperation Amid Broader Tensions

The renewed barter agreement signals an enduring spirit of cooperation between NASA and Roscosmos, even as geopolitical tensions remain high between the U.S. and Russia. Despite challenges, both agencies have consistently emphasized the importance of maintaining international collaboration aboard the ISS, which has operated as a symbol of peaceful scientific partnership for more than two decades.

The ISS is currently slated to operate through at least 2030, with discussions ongoing among international partners regarding the eventual transition to commercial space stations in low Earth orbit.