NASA astronaut Ricky Arnold at the end of the robotic Canadarm2 during U.S. EVA-50. Photo Credit: NASA TV
Two Expedition 55 NASA astronauts ventured outside the International Space Station May 16, 2018, for a 6.5-hour-long spacewalk. They were tasked with rearranging coolant pumps and replacing external cameras and antennas.
Called U.S. Extravehicular Activity 50 (U.S. EVA-50), the primary task of the spacewalk was to move two pump flow control subassembly (PFCS) units. These devices are designed to drive and control the flow of ammonia coolant on the exterior of the ISS to regulate the temperature of the station’s power-generating equipment, according to NASA.
In 2013, a PFCS failed after an ammonia leak. It was soon replaced with a spare by astronauts and stowed on the P6 Truss before recently being remotely removed by ground teams using the Dextre robotic “hand.” This failed unit was nicknamed “Leaky” by ISS management teams.
The Dextre robotic “hand” holds onto “Leaky,” a degraded pump flow control subassembly unit that astronauts will swap with a spare for later use. Photo Credit: Norishige Kanai / JAXA
A spare PFCS, named “Frosty” was located on External Stowage Platform 1 (ESP-1). Mission managers wanted to swap the locations ...