Thursday, May 26, 2011

Spacewalkers Outfit Station

The International Space Station’s Canadarm2 is closer to having a new base of operation, giving it access to much of the orbiting laboratory’s Russian segment. Endeavour Mission Specialists Drew Feustel and Mike Fincke installed a power and data grapple fixture on the Russian Zarya module during a 6-hour, 54-minute spacewalk early Wednesday. The arm can “inchworm” its way to the new base by grasping it and then releasing the hand holding the old base to become the new end effector. A cable to provide power to that new operating base is on the to-do list for the fourth spacewalk of the mission. The spacewalkers also installed a video signal converter on Zarya and ran power cables from the U.S. segment to Zarya. That provides a backup for transmission of power from the solar arrays to the Russian segment.

Feustel and Fincke completed a job started on the flight’s first spacewalk, finishing hookup of an external wireless communications system antenna. The work was postponed because of a malfunction of one suit’s carbon dioxide gauge that caused the Friday spacewalk to be cut short. They took photos of some of their handiwork and of Zarya thrusters, and some infrared video of an experiment involving coatings with variable thermal control qualities. Mission Specialist Greg Chamitoff was their intravehicular officer and astronaut Steve Swanson served as spacewalk capcom in the station flight control room. Endeavour Commander Mark Kelly did photo and video documentation.

Feustel and Fincke used a new procedure to prepare astronauts for spacewalks. They breathed oxygen for an hour, then put on spacesuits and did “light exercise” for 50 minutes, standing and doing slow intermittent movements. The procedure avoids the overnight stay in the Quest airlock that had become standard. The Wednesday spacewalk ended at 7:37 a.m. CDT, when repressurization of the airlock began. It was the sixth for Feustel and the eighth for Fincke. It was the 247th U.S. spacewalk. The spacewalk brought the total time spent for station assembly construction and maintenance to 995 hours and 13 minutes during 158 spacewalks.

The mission’s fourth spacewalk, Friday morning, is expected to break the 1,000-hour mark. It will also be the last spacewalk by space shuttle crew members. A spacewalk during the program’s final mission, STS-135, is to be conducted by space station residents. In other activities, Pilot Greg Johnson and Mission Specialist Roberto Vittori spent much of their day stowing equipment and supplies. Station Flight Engineer Ron Garan helped out with post-spacewalk tasks. The next status report will be issued after crew wakeup or earlier if warranted.

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