14 DAY TRIAL // In an announcement made on Saturday, experts at NASA announce that astronauts aboard the International Space Station (ISS) will need to perform a third spacewalk to repair the broken ammonia pump. Initially, just two extravehicular activities (EVA) were planned, one scheduled for Saturday, and the other one for Wednesday. But the excursion made on August 7 failed to achieve all of its objectives, and so a new spacewalk is already being planned, Space reports.
The first EVA was stalled by an ammonia leak, which threatened the astronauts. ISS flight engineers Douglas Wheelock and Tracy Caldwell Dyson, who were performing the task, had to pull away, and give up trying to complete all the activities that were assigned to them for that day. The cooling system pump, which powers Loop A, therefore remains nonoperational, despite the astronauts spending more than 8 hours trying to fix it.
The goal of Saturday's EVA was to swap the broken pump with a new one. But a stuck ammonia hose was the first problem the astronauts came by. When the spacewalkers used a hammer-like tool to unjam it, they caused a significant amount of ammonia to leak into space. The hose was then reconnected, and the astronauts were told by Mission Control to wrap up their efforts for the day. “I really think we're going to end up with three EVAs. I think we're going to end up with being in this position, this risk posture, for a few more days than we intended on and planned for,” said after the EVA Mike Suffredin, who is the NASA space station program manager.
The issue confronting mission planners now is making sure that the troublesome hose can be removed without causing another ammonia spill. Engineers are currently working on developing new approaches and guidelines to making this a reality. They believe that two spacewalks will be needed to ensure that the pump is properly fixed, which would bring the total number of EVA to 3. The ISS holds four excess pumps in storage, precisely for situations such as this one.