NASA astronaut Kate Rubins and Soichi Noguchi, a Japanese astronaut who last walked in space more than 15 years ago, ventured outside the International Space Station Friday to continue solar power system upgrades and to finish wiring up a European experiment platform.The astronauts, floating in the Quest airlock compartment, switched their spacesuits to battery power at 6. 37 a.m. EST to officially kick off the years fourth spacewalk, the 236th since station assembly began in 1998.What a view! Noguchi said as he floated out of the airlock some 260 miles above the Atlantic Ocean.For identification, Rubins, call sign EV-1, is wearing a suit with red stripes and is using helmet camera No. 22. She also is equipped with a new high-definition video camera. Noguchi, call sign EV-2, is wearing an unmarked suit and using helmetcam 20.Rubins is a veteran of three spacewalks, including one last Sunday with crewmate Victor Glover. Noguchi also is a three-spacewalk veteran, but his last excursion came in 2005 during the first post-Columbia shuttle mission.Last Sunday, Rubins and Glover installed a new solar array support fixture at the base of the labs far left set of solar wings. The fixture is designed to support new roll-out solar blankets that will be installed later to boost the stations power generation.But the astronauts had problems fully seating two bolts connecting struts in the Tinker Toy-like fixture. Rubins and Noguchi planned to troubleshoot the balky bolts Friday and to finish assembly of a second solar array support fixture.Rubins then will venture to the front of the European Space Agencys Columbus laboratory module, where an external experiment platform — Bartolomeo — is attached. Once in position, she will finish making electrical and data connections between the platform and the lab module that were not completed during a January spacewalk.While Rubins works at Bartolomeo, Noguchi planned to replace a failed wireless transceiver unit on the central Unity module that is used to capture helmet camera video and radio communications during spacewalks.NASA plans to install six new ISS roll-out solar arrays, or IROSA, blankets that are scheduled for delivery later this year and next aboard SpaceX Dragon cargo ships. Additional spacewalks will be needed to install additional support fixtures and, eventually, the new roll-out blankets.The space station is equipped with four primary solar array wings, two on each side of the labs power truss. Each wing is made up of two 39-foot-wide blankets extending 112 feet in opposite directions. The first two-blanket wing was launched in December 2000 with additional pairs delivered in 2006, 2007 and 2009.Solar cells degrade over time and NASA is adding six new blankets, at a cost of 103 million, to the existing power system. Each one of the new IROSA blankets measure 20 feet wide by 63 feet long when fully extended, generating more than 20 kilowatts.Combined with the 95 kilowatt output of the original eight panels, the stations upgraded system will provide about 215,000 kilowatts of power, enough for NASA-sponsored research and anticipated commercial activity between now and the end of the decade.
Spacewalkers continue solar power system upgrade