The Expedition 74 crew spent the majority of their time maintaining science hardware and life support systems on Wednesday. The orbital residents aboard the International Space Station also pursued cardiovascular research, conducted a vision test, and performed other experiments throughout the day.

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NASA flight engineers Chris Williams and Jessica Meir partnered together inside the Kibo laboratory module finalizing the removal of botany research gear from an EXPRESS rack. Williams also swapped a sensor-packed Bio-Monitor vest and headband that he wore overnight for a spare to continue measuring his health data including blood pressure checks throughout his shift. He later videotaped alfalfa plants growing inside the Veggie facility to explore plant-microbe interactions and how plants may source nitrogen and thrive in low‑resource conditions such as a spacecraft.

Meir checked out the Cold Atom Lab, a quantum research facility that chills atoms to near absolute zero, ensuring its proper functionality after inspecting and reconnecting its sensitive fiber optic cables earlier in the week. She later joined astronauts Jack Hathaway of NASA and Sophie Adenot of ESA (European Space Agency) and took turns reading a standard eye chart for a regularly scheduled vision test.

Hathaway spent most of his day inside the Destiny laboratory module working on the orbital outpost’s oxygen generation system. He first collected water samples from the life support device for analysis by engineers on the ground. Next, he replaced a hydrogen sensor, cleaned the air intake system, then measured airflow inside the oxygen generator.

Adenot began her shift collecting her saliva samples for real time analysis aboard the station using the new APHRODITE biomedical hardware delivered aboard a SpaceX Dragon spacecraft on Feb. 14. Next, she swapped filters inside the BioLab that enables the research of microorganisms, cells, tissue cultures, small plants, and small invertebrates in microgravity. Finally, she installed a new computer system inside the Columbus laboratory module upgrading connections with scientific equipment, laptop computers, sensors, and network switches.

Station commander Sergey Kud-Sverchkov and Sergey Mikaev, both from Roscosmos, partnered together for a pair of life science investigations on Wednesday. The duo first took a controlled, progressively harder test together to observe their reactions and understand how living long term in space affects teamwork, cognitive performance, and emotional stability. Next, they took turns wearing arm, wrist, and finger cuffs that collected their blood pressure measurements helping doctors understand how weightlessness affects a crew member’s blood vessels.

Roscosmos flight engineer Andrey Fedyaev began his shift collecting a tiny blood sample from himself, spinning it in a centrifuge, then analyzing the red blood samples. Afterward, Fedyaev jogged on the Zvezda service module’s treadmill while attached to electrodes for a standard fitness test. He wrapped up his day replacing hoses, connectors, and valves that carry water removed from the station’s air by Zvezda’s dehumidifiers.

Learn more about station activities by following the space station blog, @space_station on X, as well as the ISS Facebook and ISS Instagram accounts.

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