After three days of studying how bones heal, the astronauts on Expedition 68 are cleaning up and getting ready for their next spacewalk. The three cosmonauts on the International Space Station kept working on space physics and taking pictures of Earth. They also kept orbital lab systems running.

After three full days of bone healing research, NASA Flight Engineers Josh Cassada and Frank Rubio are cleaning up the biology research equipment and finishing up sample processing. Inside the Kibo laboratory module, the two people worked on the samples and put them in science freezers. 

These samples will be put on a future SpaceX Dragon cargo mission to bring them back to Earth, where they will be analysed and compared to control samples in labs. This week, a lot of work was done to study bones in Kibo's Life Science Glovebox. The two astronauts cleaned the box and its parts.

Cassada also started working on space agriculture today. She took leaves from thale cress plants living in the Advanced Plant Habitat so that they could be stored and studied back on Earth. Later, he took care of tomato plants that were growing in the Veggie space botany facility as part of the Veg-05 experiment. The Columbus labs module is where both studies are being done.

Koichi Wakata, an astronaut with the Japan Aerospace Exploration Agency (JAXA), looked into ways to make it possible for astronauts on long-term missions to the Moon, Mars, and other places to get food when they need it. 

Engineered microbes, like yeast, are used in the technology demonstration to make sure that food production in space is safe and easy and to stop nutrients from going bad after they have been stored for a long time.

The next space station to continue improving the power generation system of the orbiting lab is scheduled for Feb. 2. Two spacewalkers in their Extravehicular Mobility Units (EMUs), or spacesuits, will leave the Quest's airlock in their suits to finish putting a modification kit on the starboard truss structure. By putting in the hardware, the space station will be ready for the next roll-out of its solar array. Before the next spacewalk, the gloves and tethers on the spacesuits were checked.

Commander Sergey Prokopyev ran more space physics experiments on Thursday as he studied how clouds of highly charged particles, or plasma crystals, act in microgravity. Flight Engineer Dmitri Petelin of Roscosmos spent the day fixing life support systems before working with cosmonaut Anna Kikina to scan their eyes with ultrasound. 

Kikina went back to watching Earth and used ultraviolet imaging equipment to make a map of how the Earth's atmosphere glows at night.