3 Sept 2025

Expedition 73 continued observing bone stem cells on Wednesday to learn how to protect the skeletal system in microgravity and ensure crew health on long duration space missions. The International Space Station residents also installed advanced computer hardware and practiced an emergency drill as a SpaceX Dragon cargo spacecraft boosted the orbital outpost’s altitude.

NASA Flight Engineer Jonny Kim was back inside the Kibo laboratory module processing bone stem cell samples to help doctors understand the molecular changes crew member’s bones experience during a spaceflight. The human-provided samples were delivered recently aboard a SpaceX Dragon cargo craft and are being treated with a therapeutic agent for a closer look and a better understanding of space-caused bone loss. After a period of incubation during the research activities, the specimens are stowed in a science freezer to be returned back to Earth aboard Dragon for retrieval and analysis.

Before the start of the bone study, Flight Engineer Kimiya Yui of JAXA (Japan Aerospace Exploration Agency) activated the Life Science Glovebox for Kim to begin his experimental work. Yui then moved on and set up an artificial gravity-generating incubator to study the fermentation and brewing process of sake yeast. At the end of his shift, the two-time station visitor installed the Axiom Data Center Unit-1 in the Destiny laboratory module to test processing and data storage and advanced manufacturing applications on orbit.

Flight Engineers Zena Cardman and Mike Fincke continued unpacking some of the science, supplies, and hardware packed inside Dragon on Wednesday. As the crew worked during the second half of its shift, the external reboost kit installed inside Dragon’s trunk, an independent propellant system, powered the spacecraft’s two Draco engines for several minutes in a demonstration of its ability to maintain the station’s altitude.

Cardman and Fincke also partnered together clearing up space and organizing cargo inside the Permanent Multipurpose Module. Cardman later replaced and repaired hardware on the cupola’s robotics workstation. Fincke reviewed procedures and gathered hardware for an upcoming physics study to develop and design new materials, such as pharmaceuticals, in space.

Station Commander Sergey Ryzhikov and Flight Engineer Alexey Zubritsky, both from Roscosmos, started their shift practicing an emergency evacuation drill with Kim. The three crewmates, who launched to the orbital outpost aboard the Soyuz MS-27 spacecraft, trained on a computer the procedures they would use to quickly board their Soyuz and undock from the station in the unlikely event of an emergency.

Afterward, Ryzhikov and Zubritsky joined fellow Roscosmos cosmonaut Oleg Platonov and photographed crew activities documenting research work, exercise, maintenance duties, and more. Platonov spent the majority of his shift inside the Nauka science module cleaning components on its ventilation system.

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Astronauts Kimiya Yui of JAXA (Japan Aerospace Exploration Agency) and Zena Cardman of NASA unpack some of the science, supplies, and hardware delivered aboard the SpaceX Dragon cargo spacecraft and begin installing the new gear inside the International Space Station.