![NASA astronaut Scott Tingle](https://blogs.nasa.gov/spacestation/wp-content/uploads/sites/240/2018/04/blog_iss055e018690.jpg)
A wide variety of life science is being explored today aboard the International Space Station as Expedition 55 crew members prepare for a spacewalk planned for next month. The space residents also continued the upkeep of the orbital lab while robotics controllers set up an external experiment.
Japanese astronaut Norishige Kanai split his time today between tending mice and removing sensors attached to his arm. The rodents are being observed to detect the chemical signals that lead to muscle and bone loss in space and to provide therapies to keep astronauts healthy. Kanai also removed an armband monitor and sensors he wore for 36 hours that recorded alterations in his circadian rhythm caused by living in space.
Flight Engineers Ricky Arnold and Drew Feustel are getting ready for a May 16 spacewalk to swap out thermal control gear that circulates ammonia to keep station systems cool. The duo readied their spacewalk tools today then dumped water and purged gases from a pair of U.S. spacesuits.
Scott Tingle of NASA worked inside the Harmony module today to replace a deteriorating Pump Package Assembly (PPA) with a spare device. The PPA is a thermal control system that provides water cooling to station payloads and critical systems avionics.
Science is also taking place outside the space station and robotics controllers are working to transfer a tray for the materials exposure experiment (MISSE-FF) outside of the Kibo lab module through the lab’s airlock for reconfiguration tomorrow. The complex robotic maneuvers are remotely controlled from the ground and use not only the Canadarm2 robotic arm but also the fine-tuning robotic hand known as Dextre. MISSE-FF will test materials, coatings, and components in the harsh environment of space.
Also, overnight, Russian flight controllers sent commands to deorbit the unpiloted ISS Progress 68 cargo craft that had been orbiting for the past month for engineering test following its undocking from the station March 28. It burned up harmlessly in the Earth’s atmosphere over the southern Pacific.