NASA considers spacewalk option to fix space station cooling problem

NASA says it is considering the option of a spacewalk to fix a cooling problem aboard the International Space Station. Engineers have been working to regulate temperatures in one of two cooling loops on the ISS affected by the malfunction last week of a flow control valve in a cooling pump on the station's starboard truss, the space agency said Monday. The valve that helps control the flow of ammonia to cool station systems stopped working last Wednesday, resulting in a drop of temperature in one cooling loop that required the shutdown of some support systems on the station. Engineers have attempted to fine-tune the position of an isolation valve associated with the flow control system to assist the faulty valve in regulating the affected cooling loop's temperatures, NASA said. Mission controllers said they are considering having Expedition 38 astronauts Rick Mastracchio and Michael Hopkins conduct a suite of spacewalks beginning Thursday to replace the faulty pump.