Faulty Ammonia Pump Removed During Spacewalk

Expedition 24 Flight Engineers Doug Wheelock and Tracy Caldwell Dyson have completed the second of three spacewalks to remove the failed ammonia coolant Pump Module on the S1 truss of the International Space Station that failed July 31. Their spacewalk ended at 1553 EDT Wednesday.

NASA Image

Wheelock successfully closed the quick disconnect valve for the final fluid connector for the failed ammonia pump module. Then he successfully detached the final fluid line from the failed ammonia pump module. Caldwell Dyson disconnected five electrical and data cables while Wheelock broke torque and removed four bolts from the old pump. The pump module then was extracted from the truss through the use of a grapple bar and installed on a payload bracket on the Mobile Base System on the station’s truss.

With the failed pump module safely stowed on the truss, Caldwell Dyson prepared the spare pump for installation on the next spacewalk, which is scheduled for Monday, August 16.  A fourth spacewalk may be required to clean up the work site.

In response to the power reconfiguration steps last weekend, the science team worked quickly to establish a plan to preserve experiment samples in the Japanese Experiment Module freezer. The on-orbit crew was able to transfer all the samples from the freezer in the Kibo laboratory to an operating freezer. No sciences samples were lost due to the pump module anomaly.

NASA Image

While the crew schedule has been interrupted to support the newly added spacewalks, the payload ground teams have been working closely with mission controllers to preserve and re-plan high priority activities. Other activities that can be rescheduled with little or no impact are being postponed to a later date.

FMI: www.nasa.gov