NASA astronauts Barry Wilmore and Terry Virts are counting down to the first of three assembly spacewalks set to begin Friday at 7:10 a.m. EST. The duo checked out their rescue jet packs they would use in the unlikely event they became untethered from the International Space Station. The spacewalks will prepare the station for new commercial crew vehicle docking ports.

› Read more about the upcoming spacewalks

The latest supply ship to dock to the orbital lab, Progress 58, had its hatches opened Wednesday morning, following its Tuesday arrival. The Expedition 42 crew members will now begin unloading several tons of food and supplies that will replenish the station residents for the next few months.

Meanwhile, the six-member crew continued the International Partners’ mission of conducting advanced microgravity science. Ultrasound eye scans and blood pressure checks were conducted with remote guidance from doctors on the ground today. The crew also studied cell cultures grown on orbit and explored techniques to improve Earth observation photography.