HOUSTON - Despitea late start caused by airlock glitches, two Atlantis shuttle astronauts pushedthrough their mission's final spacewalk to help deploy a vital new solararray radiator among other maintenance outside the International Space Station(ISS).
Clad inNASA spacesuits, Atlantis spacewalkers JosephTanner and HeidemarieStefanyshyn-Piper spent more than six hours outside the ISS on assorted oddjobs and the liberation of the stowed Port 4 truss radiator, which they helpeddeliver earlier this week.
"Yes, that'sa deploy," Tanner said as he and Stefanyshyn-Piper watched the accordion-likeradiator unfold at 9:05 a.m. EDT (1305 GMT).
Theradiator, designed to cool systems for the space station's new P4 solar arrays unfurledyesterday, will now allow those electricity-generating wings to power theP4 truss independently of the ISS, mission managers said Thursday. The arraysand radiator are part of the $372million Port 3/Port 4 integrated truss structure hauled to the ISS byAtlantis to jump start the outpost's stalledconstruction.
"These guysmake it look really easy and their flight is a very difficult flight," said MichaelSufferdini, NASA's ISS program manager, of Atlantis' six-astronaut STS-115 crewin a Thursday briefing. "I couldn't ask to a better start, a restart, toassembly."
Tanner and Stefanyshyn-Piperbegan their six-hour, 42-minute spacewalk at 6:00 a.m. EDT (1000 GMT), about 45minutes late, due to a tripped circuit breaker in the station's Quest airlock.The glitch caused a depressurization pump to shut down, but resulted from an electricalspike and not a pump short circuit, NASA officials.
Many of thetasks planned for today's spacewalk were performed earlier this week by otherSTS-115 astronauts who'd finished their work early.
In additionto priming the new solar array radiator for deployment, Stefanyshyn-Piperand Tanner repaired a defunct S-band antenna support assembly, a task that tookmuch longer than planned as flight controllers and the spacewalkers struggledto move into the proper position.
"We, insidehere, think a little drama is always good," STS-115 astronaut Steven MacLean,who oversaw his spacewalking crewmates from inside Atlantis.
WhileStefanyshyn-Piper finished work on the S-band antenna, which will be a vitalcommunications tool for future ISS construction, Tanner wrapped the station'sprimary video and data Ku-band antenna in a protective thermal cover.
Tanner alsosecured bolts in place on the station's Port 6 truss solar array truss, whichreaches nine stories above the orbital outpost and is the highest point on theISS.
"Well that'sa pretty above average view I've got to now," Tanner said while looking downat the ISS, Atlantis and the entire Earth.
He also madeshort movies of Atlantis' starboard wing leading edges - covered in a carboncomposite heat shield - with an infraredvideo camera before heading back inside the ISS.
Today'sspacewalk marked the seventh for Tanner - a veteran of extravehicularactivities (EVAs) - and the second for Stefanyshyn-Piper, whose experienceTanner has said will be vital for future ISS assembly.
"This isgood experience for you so you can teach others about it," Tanner told Stefanyshyn-Piper."Your next job is to teach."
Stefanyshyn-Piperworked to remove a series of tough bolts from cinches and restraints to free thestation's new radiator, prompting accolades from her spacewalking partner.
"You'regoing to outdo Xena," Tanner said, referring to television's warrior princess.
Friday'sspacewalk marked the third and final EVA planned for NASA's STS-115mission. Two teams of spacewalkers spent a total of 20 hours and 19 minutes workingoutside the ISS this week.
About sevenhours and 11 minutes of that time stemmed from work by STS-115 spacewalkers DanielBurbank and StevenMacLean of the Canadian Space Agency during a Wednesdayspacewalk, a career first for both astronauts. The remaining 13 hours and eightminutes were performed by Stefanyshyn-Piper, also her first, and Tanner.
"This hasbeen a great job and a great mission," Stefanyshyn-Piper said.
Today'sspacewalk marked the 72nd EVA dedicated to ISS assembly ormaintenance, as well as the 25th staged from the station's Quest airlock.Spacewalkers have spent a total of 438 hours and 36 minutes building the orbitallaboratory.
"Maybe we'llcatch Jerry Ross," joked Tanner, referring to U.S. spacewalking record holderJerry Ross, who racked up 58 hours and 18 minutes during his NASA astronautcareer.
Tanner isnow the fourth most experienced spacewalker in history, with a total of 46hours and 29 minutes in seven EVAs, after NASA astronaut Steve Smith, Ross andall-time champion Russian cosmonaut Anatoly Solovyev, who staged 16 careerspacewalks during 77 hours and 41 minutes of orbital work.
"I don'tthink there are enough shuttle flights to catch Jerry Ross," Stefanyshyn-Piperreplied.
Mission controllers awoke Atlantis' six-astronautcrew to the tune of the Eagles' "Hotel California," chosen for Tanner by hisfamily.
"That songreminds me of some great traveling adventures, sort of like this one," Tannersaid. "It's gonna be a great day."
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