UNDATED (WKOW) -- NASA is still working on repairing the cooling system at the International Space Station.
On Wednesday, astronauts spent their second space walk in five days removing an ammonia line.
But the work is not over yet; on Sunday, another spacewalk will have to replace the failed pump that broke down earlier in August.
Research at the space station is on hold right now as the station is only operating with half of its cooling capabilities.
If the system fails it could be dangerous, which is why NASA is working fast and has made the mission its top priority.
The organization says this is the most challenging repair in the 12-year history of the orbiting lab.