Original URL: http://www.theregister.co.uk/2010/08/02/iss_pump/
ISS suffers coolant pump failure
'No danger' from ammonia system breakdown
The International Space Station's crew is "not in any danger" following the failure of an ammonia cooling loop pump on Saturday night.
NASA explains that a circuit breaker trip preceded the breakdown of the "Pump Module for loop A that feeds ammonia to maintain the proper cooling for systems and avionics", just before midnight GMT.
The agency says that "an attempt overnight Sunday to close the circuit breaker and restart the Pump Module was not successful", but assures: "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."
Expedition crew members Doug Wheelock and Tracy Caldwell Dyson were due to venture outside the orbiting outpost on Thursday to "install a power extension cable to the Unity module prior to the delivery of the Permanent Multipurpose Module on the STS-133 mission in November and to install a Power and Data Grapple Fixture to the Zarya module to support future robotics work".
This, though, will now be deferred to a later date. Caldwell Dyson and Wheelock will instead be tasked with swapping out the failed Pump Module, which sits on the station’s S1 truss. There are a couple of spares sitting on external stowage platforms, and it will require two spacewalks to first fit the new unit, then connect up fluid and electrical lines.
NASA has more on the pump failure here. ®