Expedition 75 Crew Readies Tuesday Spacewalk to Swap Space-to-Ground Antenna

The International Space Station's Expedition 75 crew closed the work week on August 21 preparing for a Tuesday spacewalk to finish installing a high-speed antenna on the orbital outpost. The excursion, set for 8:35 a.m. EDT, will complete the swap of a space-to-ground antenna on the Z1 truss segment above the Unity module.

The crew also spent the week studying new space exercise techniques, examining the human respiratory system, and completing an Earth observation session, mixing spacewalk preparation with research and hardware maintenance across the station's modules.

NASA flight engineer Anil Menon and ESA astronaut Sophie Adenot took turns inside the Quest airlock on Friday, organizing the tools they will use during the spacewalk. The pair configured their safety tethers, checked the bags carrying specialized tools and parts, and staged them inside Quest. Adenot studied her spacewalking procedures on a computer using 3D animation software depicting her tasks outside the station.

Menon and Adenot will be assisted by NASA flight engineer Jack Hathaway and station commander Jessica Meir. Hathaway and Meir studied the Canadarm2 robotic arm maneuvers needed to support the spacewalkers. During the excursion, Menon will ride Canadarm2 and retrieve a spare antenna released by Adenot from an external platform. The two will translate to Z1, install the antenna, and make the electrical and data connections required to activate high-speed transmissions with mission control. Adenot will then hand Menon the failed antenna, which they will install on the same external platform that housed the spare, completing the swap. If time allows, they will replace a retroreflector on the forward port of the Harmony module to improve navigation, tracking, and alignment data for visiting spacecraft such as the SpaceX Dragon.

The crew also advanced exercise research. Hathaway collected a blood sample for the Muscle Stimulation experiment, then applied electrodes to his legs that sent electrical signals stimulating his muscles while strapped in the Columbus laboratory module. Adenot wore the EasyMotion-2 suit packed with electrodes that triggered muscle contractions as she jogged on the Tranquility module's treadmill. Results may enhance space exercise and enable faster muscle recovery after returning to Earth's gravity. Menon removed a scientific payload exposed to vacuum from the Kibo laboratory module's airlock, and Meir refilled a spacesuit tank and a liquid cooling and ventilation garment with water for thermal conditioning. Roscosmos flight engineer Andrey Fedyaev wore an acoustic sensor around his neck to record rapid exhalation for respiratory research, then documented radiation measurements from the Nauka, Zvezda, and Zarya modules. Pyotr Dubrov and Anna Kikina uninstalled automated Earth observation gear that had photographed landmarks during the crew's sleep shift, after which Dubrov inspected ethernet cables and Kikina took inventory of lab hardware in the Roscosmos segment.

The high-speed antenna installation supports high-speed transmissions between the station and mission control, and the retroreflector replacement, if performed, improves navigation, tracking, and alignment data for visiting spacecraft including SpaceX Dragon.

The spacewalk is scheduled to begin at 8:35 a.m. EDT on Tuesday. Menon and Adenot will conduct the antenna swap on the Z1 truss, supported by Hathaway and Meir operating Canadarm2, with the Harmony retroreflector replacement to follow if time permits.