July 12th, 2006 15:53 EST
Astronauts Wrap Up Third STS-121 Spacewalk
Mission Specialists Mike Fossum and Piers Sellers successfully completed STS-121’s third and final spacewalk at 2:31 p.m. EDT today. The demonstration of orbiter heat shield repair techniques was the objective of the 7-hour, 11-minute excursion outside Space Shuttle Discovery and the International Space Station.
The spacewalkers tested repair techniques on pre-positioned heat shield materials in the payload bay. Among the tools they used were a space-certified caulk gun and a variety of spatulas to manipulate the test materials.
The duo also used an infrared camera to get a 60-second recording of two damaged tile samples. The camera is designed to capture temperature gradients that will indicate invisible damage.
Near the end of the spacewalk, Mission Control notified Sellers and Fossum that they would get extra time outside the shuttle/station complex to perform a get-ahead task. The spacewalkers relocated a grapple fixture from a cargo carrier to an ammonia tank on the S1 truss. This sets the stage for the tank's removal during a future spacewalk.
Pilot Mark Kelly coordinated the spacewalk activities and Commander Steve Lindsey oversaw shuttle and video systems. Mission Specialists Lisa Nowak and Stephanie Wilson were the robot arm operators.
Meanwhile, the Expedition 13 crew continued to load the Leonardo multi-purpose logistics module with station experiment results and other items returning to Earth. Leonardo will return to Discovery’s payload bay on Friday, setting the stage for STS-121’s departure on Saturday.