Expedition 68 astronauts are now cleaning up after three days of in-depth bone repair research as they prepare for the upcoming spacewalk. Meanwhile, the three astronauts aboard the International Space Station (ISS) continued to serve the orbiting laboratory systems, as well as space physics and Earth imaging.

NASA Flight Engineers Josh Cassada and Frank Rubio clean the biological research equipment and finish processing the samples after three full days of bone healing research. The two worked in Kibo’s lab module, processing the samples and then placing them in science freezers. These samples will be packed into a future SpaceX Dragon cargo mission for return, and then analyzed in laboratories on Earth and compared with control samples. The two astronauts also cleaned the Kibo Life Science glove box and its components, where extensive bone research work has been done this week.

Cassada also worked on space agriculture on Thursday by collecting leaves from watercress plants housed in the Advanced Plant Habitat for storage and analysis on Earth. He then looked at growing tomato plants at Veggie Space Botany for the Veg-05 experiment. Both studies take place in the Columbus lab module.

Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata has explored ways to enable on-demand food production for astronauts on long-duration missions to the Moon, Mars and beyond. The technology demonstration uses microbes or yeasts designed to provide a safe and simple environment for producing food in space and to compensate for the degradation of stored nutrients over time.

The next spacewalk is scheduled for February 2 to continue the modernization of the orbital lab’s power generation system. The two spacewalks will emerge from the Quest hatch in extravehicular mobility units (EMUs) or spacesuits to complete installation of the modification kit on the starboard beam. The hardware installation work will prepare the space station for the next solar array deployment. Gloves and spacesuit cables were checked before the upcoming spacewalk.

Commander Serhii Prokopiev continued his experiments in space physics on Thursday by investigating how clouds of highly charged particles, or plasma crystals, behave in microgravity. Flight engineer Dmytro Petelin of Roscosmos spent the day maintaining life support equipment before working with fellow cosmonaut Anna Kikina for an ultrasound eye scan. Kikina continued her observations of Earth using ultraviolet equipment to map the night glow of Earth’s atmosphere.