A Soyuz TM-31 spacecraft launched the three-person Expedition 1 crew, beginning continuous human presence aboard the International Space Station (ISS). This set the pattern of using Soyuz as both a crew transport and an on-orbit emergency return vehicle (often called a “lifeboat”).
Two days after launch, Soyuz TM-31 docked with the ISS and the Expedition 1 crew entered the station. With a Soyuz always attached for emergency return, the station could support long-duration crews safely and continuously.
After months on orbit, the Expedition 1 crew landed on Earth, completing the ISS’s first long-duration mission. The return demonstrated the basic “ferry” concept: bring a crew up, keep the spacecraft docked for emergency use, then return the outgoing crew.
Soyuz TM-32 carried a short-term visiting crew that included Dennis Tito, widely recognized as the first paying visitor to the ISS. The flight still supported station operations by swapping a Soyuz and ensuring an up-to-date return vehicle remained docked.
Soyuz TM-33 launched another visiting crew and left a Soyuz docked to serve as the station’s emergency return craft. These early “taxi” missions helped keep ISS operations stable while the permanent crew program expanded.
With Soyuz TMA-1, Russia introduced the Soyuz TMA variant, an upgraded version intended to improve performance and crew accommodations. Soyuz continued to serve the same core ISS role: transporting crews and providing a docked return option.
Soyuz TMA-01M marked the start of the TMA-M modernization, replacing key analog systems with digital equipment. The upgrades aimed to simplify operations and improve reliability while keeping Soyuz as a steady ISS crew ferry.
The Soyuz MS series began, bringing further updates such as improved communications and navigation systems. This continued the long-running approach of regular incremental upgrades while maintaining the same docking-and-return role at the ISS.
While docked to the ISS, Soyuz MS-22 suffered a radiator coolant leak, raising concerns that it could overheat during a crewed reentry. NASA and Roscosmos decided the spacecraft would return uncrewed, and a replacement Soyuz would be launched to restore a safe return capability.
Soyuz MS-23 launched without a crew to replace the damaged Soyuz MS-22 and re-establish a reliable “lifeboat” at the station. This was an unusual but operationally important step: the vehicle flew like an automated cargo mission but was intended for a later crew return.
Soyuz MS-22 undocked from the ISS and returned to Earth without a crew, as planned after the coolant leak. The event showed how station operations can adapt when a docked return spacecraft becomes unsafe for a crewed landing.
Soyuz MS-24 landed in Kazakhstan carrying its returning crew, including NASA astronaut Loral O’Hara. The mission highlighted that Soyuz continued to provide routine crew return capability even as other partners also flew crew vehicles to the station.
Soyuz MS-25 returned a crew that included cosmonauts Oleg Kononenko and Nikolai Chub after a record-long single ISS expedition, along with NASA astronaut Tracy Caldwell Dyson. The landing underscored Soyuz’s continuing role as a dependable return path for long-duration station crews through 2024.
Soyuz Ferry Flights to the ISS: Crewed Transport and Return Missions (2000–2024)