Mike Fincke Assumes ISS Command for Expedition 74 from Sergey Ryzhikov

The International Space Station (ISS) is scheduled for a formal change of command on Sunday, December 7, 2025, marking the conclusion of Expedition 73 and the commencement of Expedition 74. This operational transition is formalized during a ceremony aboard the station at 10:30 a.m. Eastern Daylight Time (EDT), officially transferring command responsibilities from outgoing Commander Sergey Ryzhikov of Roscosmos to incoming Commander, NASA Astronaut Mike Fincke. This procedure underscores the sustained international collaboration required to operate the ISS, which has maintained continuous human presence since November 2000.

The conclusion of Expedition 73 is directly linked to the departure schedule of its core crew. Following the handover ceremony, Commander Ryzhikov and Flight Engineer Alexey Zubritsky are slated to undock their Soyuz MS-27 spacecraft at 8:41 p.m. EDT on Monday, December 8, 2025. Their return trajectory is set to conclude with a landing in Kazakhstan at 12:04 a.m. EDT on Tuesday, December 9, 2025, concluding their approximately eight-month tenure in orbit. Mission control centers in Houston and Moscow will coordinate trajectory corrections and recovery efforts based on this precise timeline.

Preparations for the rotation involved focused activity from both the departing and arriving crews. Ryzhikov and Zubritsky completed essential final tasks, including packing research cargo and personal effects within the Soyuz MS-27 vehicle. Simultaneously, the incoming Expedition 74 crew engaged in operational checks and scientific preparations. NASA Flight Engineer Jonny Kim, on his inaugural flight, received assistance from NASA Flight Engineer Chris Williams with the installation of his spacesuit helmet, a vital safety procedure. Scientific work continued throughout the transition; Flight Engineer Zena Cardman performed a microgravity test assessing Williams' retinal response, while Expedition 74 members, including Sergey Kud-Sverchkov and Sergei Mikaev, conducted routine health monitoring and microbial sample collection.

The rotation also involved concluding external hardware tasks. JAXA Flight Engineer Kimiya Yui finalized the deployment process by uninstalling the NanoRacks CubeSat deployer after successfully releasing several small satellites. This mission marks a significant career milestone for several participants, as it is the first spaceflight for both Kim and Zubritsky, contrasting with Commander Ryzhikov’s extensive experience across three space missions. The ISS remains a collaborative project involving five space agencies, serving as a unique laboratory for testing technologies and conducting research relevant to both space exploration and terrestrial applications.

Mike Fincke's assumption of command for Expedition 74 ensures continuity in the complex research schedule spanning materials science, human physiology, and Earth observation. The ISS continuously supports dozens of simultaneous experiments, requiring coordination between ground control teams across multiple continents. The smooth procedural handover from Ryzhikov to Fincke on December 7, 2025, guarantees that ongoing scientific investigations, such as those related to radiation effects or advanced life support technologies, proceed without interruption in the dynamic environment of low Earth orbit.