Astronauts Wrap Up Third Spacewalk

Astronauts Piers Sellers and Mike Fossum wrapped up the third and final spacewalk for space shuttle mission STS-121. During the 7-hour, 11-minute spacewalk, they demonstrated techniques for repairing the shuttle’s heat shield if it was damaged during launch. The mock repairs were made using a special “space caulk gun” and several spatulas to spread on the caulking materials. Discovery will detach from the station on Saturday to return to Earth.

The third and final spacewalk of the STS-121 space shuttle mission will be the focus of today’s space activities.

Mission Specialists Mike Fossum and Piers Sellers will test techniques to inspect and repair damage to an orbiter’s heat shield. The 6.5-hour spacewalk from the Quest airlock is scheduled to start at 6:13 a.m. CDT.

Sellers and Fossum will set up tools and a foot restraint on the station robotic arm. Sellers will position himself on the arm, operated by Mission Specialists Lisa Nowak and Stephanie Wilson. He will use an infrared camera to record about 20 seconds of imagery as the arm, and Sellers, move along the shuttle’s wing leading edge.

Sellers, designated EV1 and wearing the spacesuit with red stripes, will meet EV2 Fossum, in the all-white suit, in Discovery’s payload bay. There they will set up the worksite for the repair tasks. A pallet with 12 reinforced carbon-carbon panels is pre-positioned in the payload bay. Eight are pre-damaged and will be the subject of the repair test. Two are blank, to be used as a work palette, and the last two are for further imaging by the infrared camera.

Sellers and Fossum will use a variety of tools and methods for the repair work demonstration including a space-certified caulk gun and a variety of spatulas to manipulate the test materials.

They hope to finish demonstrations on at least two of those samples. Then they’ll do a 60-second recording using the IR camera of two other damaged tiles. The camera is designed to capture temperature gradients that will indicate invisible damage.

If they have time, they may take additional photos of some shuttle panels and move the fixed grapple bar in the shuttle payload bay.

The spacewalkers will clean up the worksite and inspect their spacesuits. Then Fossum will ride the robotic arm back to the airlock, again taking video of the wing leading edge as he passes it. Sellers will make his own way back.

Pilot Mark Kelly will again serve as the intravehicular activities officer. Commander Steve Lindsey will oversee the shuttle systems and spacewalk operations.

While the shuttle crew is helping with the spacewalk, repacking of the multi-purpose logistics module Leonardo will continue. The Expedition 13 crew, Commander Pavel Vinogradov, and Flight Engineers Jeff Williams and Thomas Reiter, will put experiment results, unneeded equipment and garbage into Leonardo.

The STS-121 crew woke this morning at 12:08 a.m. to “I Believe I Can Fly,” played for Wilson. The Expedition 13 crew was awakened 30 minutes later.

The next STS-121 mission status report will be issued Wednesday evening, or earlier if events warrant.

Original Source: NASA News Release