Crew Swaps Commanders, Waits for Departure, and Conducts Muscle and Blood Research
August 5, 2025
Muscle stimulation and blood circulation research topped the 11-member Expedition 73 crew’s schedule on Tuesday helping doctor’s ensure astronauts stay fit and healthy on long-duration missions.
The International Space Station residents also swapped commanders as four crewmates prepare for return to Earth.
Astronauts living and working in space exercise seven days a week to prevent space-caused bone loss and muscle atrophy.
Careful attention by specialists on the ground and sophisticated workout gear on the station help protect a crew member’s bones and muscles, as well as their cardiovascular and respiratory systems.
Now researchers are exploring electronic muscle stimulation as a way to supplement space exercise and reduce the reliance on bulky, complicated training equipment.
For the muscle study, NASA Flight Engineer Nichole Ayers attached electrodes to her legs after working out on the advanced resistive exercise device and jogging on the COLBERT treadmill.
Next, NASA Flight Engineer Jonny Kim sent small electrical signals to the electrodes using biomedical gear that stimulated the leg muscles.
Doctors will review the data to understand how the muscular system responds to electrical stimulation to potentially benefit future missions.
The orbital outpost’s newest flight engineers, Mike Fincke from NASA and Kimiya Yui from JAXA (Japan Aerospace Exploration Agency), took turns researching how blood flows from the brain to the heart in microgravity.
Sensors on their neck and chest measured blood volume changes in their upper body caused by body fluids pooling toward an astronaut’s head. Results may help prevent cardiovascular disorders both on Earth and in space.
Roscosmos cosmonauts Sergey Ryzhikov and Alexey Zubritsky also explored how living in space affects blood circulation monitoring how blood flows from the heart to the arms and hands.
The duo used electrodes and blood pressure measurements to give doctors new insights and prevent space-linked symptoms such as vascular stiffness and stress caused by microgravity and radiation.
Ryzhikov took command of the orbital outpost today during a short ceremony when JAXA astronaut Takuya Onishi handed over his leadership responsibilities to the veteran cosmonaut.
Ryzhikov will lead the Expedition 73 mission until December when he, Zubritsky, and Kim enter their Soyuz MS-27 spacecraft, undock from the Prichal module, and ride back to Earth.
Onishi now turns his attention to returning to Earth this week with Ayers, NASA astronaut Anne McClain, and Roscosmos cosmonaut Kirill Peskov.
Following a weather review on Tuesday, NASA and SpaceX now are targeting undocking no earlier than 12:05 p.m. EDT, Thursday, Aug. 7.
For this undocking opportunity, splashdown is targeted at approximately 11:58 a.m., Friday, Aug. 8, off the coast of California.
Mission teams elected to skip an undocking opportunity on Wednesday, Aug. 6, due to high wind predictions in the splashdown zones.
McClain joined Zena Cardman, NASA’s SpaceX Crew-11 commander, on Tuesday and transferred space station emergency hardware from the departing Dragon to the newly-arrived Dragon.
The Dragon commanders also partnered together inside the Columbus laboratory module setting up research gear to explore manufacturing high-quality optical fibers in space to overcome Earth-induced imperfections.
New Roscosmos Flight Engineer Oleg Platonov began his shift setting up Earth observation gear to image Earth landmarks in a variety of wavelengths. He then joined departing cosmonaut Peskov to begin relieving him of his orbital duties.
https://www.nasa.gov/blogs/spacestation/2025/08/05/crew-swaps-commanders-waits-for-departure-and-conducts-muscle-and-blood-research/