American astronauts had to take extra precautions due to ammonia spilled from the ISS cooling system
US astronauts Victor Glover and Mike Hopkins made their last spacewalk on Saturday as part of the current expedition, the Associated Press reported, citing NASA. During the spacewalk, the astronauts had to take additional precautions due to the possible ingestion of toxic ammonia on their suits, spilled from the external cooling system of the International Space Station.
Victor Glover and Mike Hopkins had no trouble dismantling a pair of old jumper cables to remove the toxic substance still in the wires. However, so much ammonia escaped from the first hose that mission control operators began to fear that some of the frozen ammonia “flakes” might end up on the astronauts’ suits.
Hopkins speculated that several ice crystals may have gotten onto his helmet. As a result, MCC decided to “play it safe” so that ammonia would not get inside the ISS and would not pollute the cabin atmosphere. To reduce the risk of ammonia ingress, the astronauts used long instruments and stayed away from the jet nozzles.
After the ammonia hoses were emptied, Glover and Hopkins moved one closer to the access hatch in case the cable was needed at the opposite end of the station. Ammonia hoses were installed on the ISS several years ago after a leak in the cooling system.
By the end of the nearly seven-hour spacewalk, the astronauts had spent enough time under the sun for the remaining ammonia to evaporate from the surface of their suits.
According to the Associated Press, this was the sixth and final spacewalk for a US-Russian-Japanese crew of seven. Five of the six exits were conducted under the direction of NASA.