NASA News about troubleshooting
December 18, 2013
Orbital Sciences’ Cygnus spacecraft, atop its Antares rocket, now will launch no earlier than mid-January.
- The postponement of the Antares launch will allow ample time for the station crew to focus on repairing a faulty pump module that stopped working properly on Dec. 11.
- NASA currently plans for two Expedition 38 astronauts to venture outside the space station Dec. 21, 23 and 25. NASA astronauts Rick
- Mastracchio and Mike Hopkins will remove a pump module that has a failed valve.
- They will replace it with an existing spare that is stored on an external stowage platform. The pump is associated with one of the station’s two external cooling loops, which circulate ammonia outside the station to keep both internal and external equipment cool.
- Each of the three spacewalks will begin at 7:10 a.m. and is scheduled to last six and a half hours. NASA TV coverage will begin at 6:15 a.m.
(Inside crew modules, the active thermal control system uses water for heating and cooling. Air passes heat to the internal system in the air conditioner, which also collects water from the air’s humidity for system reuse.
The 2010 a pump failure in Loop A involved replacement of the pump during three spacewalks that August.
“That was a failure to be able to move the ammonia,” said Kenny Todd, ISS Mission Operations Integration Manager.)
- “Here we have a failure in controlling the temperature of the ammonia. The valve is basically a mixing valve, which helps regulate the temperature of the circulating ammonia. While it’s in the same pump module, it’s in a different area,” Todd said.
- “Everything we can do is being done,” Todd said. “The system is good and stable. The crew is in good shape. All the right folks on the ground are looking at the problem and trying to assess exactly what the root cause is and what our options are to continue moving forward.”