A fourth spacewalk needed for coolant pump

Doug Wheelock and Tracy Caldwell Dyson succeeded in removing a failed coolant pump during a spacewalk on Wednesday. (image credit NASA)

Spacewalking astronauts had to muscle free a broken coolant pump at the International Space Station Wednesday. A fourth spacewalk likely will be required later to wrap up loose ends and move the old pump to a permanent stowage location. Wheelock and Caldwell Dyson spent 7 hours and 26 minutes during their second coolant system repair spacewalk, removing the fourth and final ammonia line, disconnecting five electrical cables, loosening four bolts, and moving the 780-pound pump module to a nearby attachment fitting. They also prepared the replacement pump for installation by disconnecting three of its five electrical lines. The ammonia pump failed July 31, leaving the space station with just one coolant system to dissipate the heat generated by the lab's electronics. NASA say's the astronauts should be safe during the peak of the
Perseid meteors showers as the Earth passes through the orbit of a comet called Swift-Tuttle. Spacewalk set for Monday.