Tue, March 24, 2009
WASHINGTON, March 21 (Xinhua) -- Two astronauts from U.S. spaceshuttle Discovery's seven-member crew completed the second of three planned spacewalks Saturday to make preparation for NASA's future space shuttle mission and the debut flight of a Japanese cargo ship.
The NASA TV shows that Steven Swanson and Joseph Acaba exited the space station at around 0:51 p.m. EDT (1651 GMT) to start the outing, which lasted about six and half hours. It's Swanson's fourth spacewalk of in his career and Acaba's first.
Their primary job is loosening connections on batteries on the external Port 6 truss, ready for their replacement on a later mission in June.
The two also installed a GPS antenna to the outside of the station's Japanese module. The GPS device will help guide the Japanese HTV robotic spacecraft, a cargo transfer vehicle to be put into operation later this year.
The autonomous craft will supply the station's Kibo laboratory with water, food and scientific materials, and could also resupply the rest of the station if needed.
Other tasks include: outfitting the station's truss with attachments for experiments and cargo platforms; using an infrared camera to photograph radiator panels so engineers can assess how they have withstood the harsh space environment.
Two astronauts from Discovery's crew performed the first spacewalks Thursday and successfully installed the International Space Station's fourth and final set of solar array wings. Astronauts unfurled the solar wings Friday, bringing the 10-year-old space station to full power, which is critical for boosting science research and allowing the crew to double to six.
The space station's six solar wings already are in place. The new ones bring the number to eight, with four on each side.
Each solar array wing has two 115-foot-long (35 meters) arrays, for a total wing span of 240 feet (73 meters), including the equipment that connects the two wings and allows them to twist as they track the sun. Altogether, the station's arrays can generate as much as 120 kilowatts of usable electricity -- enough to provide about forty-two 2,800-square-foot (260 square meters) homes with power.
One more spacewalk is planned next Monday during Discovery's mission.
Discovery was launched into space last Sunday night. During its stay with the station, three spacewalks will be conducted by astronauts. If all goes well, it is scheduled to undock from the station on March 25, towards a planned March 27 landing at the Kennedy Space Center in Florida.
