International Space Station (ISS) Expedition 51 Commander Peggy Whitson, ex-KC5ZTD, and Flight Engineer Jack Fischer, K2FSH (ex-KG5FYH), undertook a nearly 3-hour spacewalk to replace a faulty computer relay box and install a set of antennas to enhance radio communication on future spacewalks. This 10th spacewalk for Whitson moves her into 3rd place all-time for cumulative spacewalking time. This was Fischer’s second spacewalk.

The computer relay unit failed on May 20. The ISS has two but needs one for a backup. The units regulate the operation of radiators, solar arrays, and cooling loops as well as route commands to other station systems. Whitson and Expedition 50 Commander Shane Kimbrough, KE5HOD, had installed the failed computer relay box during a March 30 spacewalk.