Two astronauts, Drew Feustel and Ricky Arnold of NASA, carried out the fifth spacewalk of 2018 on May 16, swapping out cooling components on the exterior of the International Space Station.

According to information provided by NASA, the astronauts were fixing the station’s pump flow control subassembly, which is one of the instruments used to regulate the station’s flow of ammonia coolant. This coolant is used to maintain temperatures for the station’s delicate hardware.

This footage shows the astronauts on their spacewalk. Credit: NASA via Storyful