U.S. space officials planned emergency repairs Monday after a failure of the cooling system on the International Space Station that has forced astronauts to re-route power. One of the cooling loops shut down late Saturday, triggering alarms on the orbiting station, which currently is occupied by three Russian and three American astronauts. An attempt late Sunday to close the circuit breaker and restart the pump module that feeds the vital ammonia to the cooling system failed, the National Aeronautics and Space Administration (NASA) said. Astronauts shut down two of the gyroscopes that position the station as they re-routed power from the Destiny Laboratory research module to keep the temperature system stable. One gyroscope was later restarted, NASA said, adding that temperatures are a little higher than normal, but within normal parameters and stable. "The station is in a stable configuration with most systems receiving cooling and many systems operating with redundancy following the installation of jumper cables from the Destiny Lab's power system overnight," NASA said in a statement. "The crew is not in any danger and is monitoring systems on an otherwise off-duty day." Despite NASA's reassurances, the agency approved a preliminary plan for two U.S. astronauts to conduct a spacewalk to get a replacement pump module. "Although a final decision on a new spacewalk plan is still pending engineering and timeline analysis, the most likely scenario would call for an initial spacewalk no earlier than Thursday ... to replace the pump module and structurally bolt it into place, ... with an additional spacewalk by the duo two or three days later to mate fluid and electrical connections," it said. According to NASA figures, without thermal controls, the station's sun-facing side would heat to 121 degrees Celsius while its dark side would cool to negative 157 degrees.
