After attempting to fix the problem remotely, NASA has confirmed that there is a malfunctioning flow control valve causing temperature fluctuations on the International Space Station.
This past week, approximately half of the space station’s temperature control functionality shut down, which forced the crew to power off all nonessential equipment. While the astronauts living aboard are safe and comfortable, NASA wants to ensure that the cooling system is operating at full level and to perform preventative maintenance to avoid any potential issues in the future.
To do this, Expedition 38 astronauts Michael Hopkins and Rick Mastracchio will perform a series of spacewalks to install a 780 pound spare pump. Back in 2010, a similar spacewalk took place to install a pump on the International Space Station, and it took three days to complete. Based upon experiences from that mission, Hopkins and Mastracchio will need to disconnect five power and data lines, three 1.5 inch ammonia lines, and a coolant line spanning only a half inch in length. After replacing the spare pump module, it is vital for the astronauts to attach these lines as quickly as possible to the control box to prevent a potential pressure loss.
The first of these spacewalks has been scheduled on December 21st and has effectively forced NASA to postpone the Cygnus cargo mission, originally scheduled for December 19th.