HOUSTON - The six-astronaut crew of NASA's shuttle Atlantis had little time to rest after reaching the International Space Station (ISS) Monday, and immediately began delivering massive new pieces of the orbital laboratory.
Atlantis' STS-115 astronauts boarded the ISS by 8:30 a.m. EDT (1230 GMT), with mission specialists Daniel Burbank and Steven MacLean jumping into tasks to move a $372 million pair of trusses and solar arrays from the shuttle's cargo bay to the end of the ISS robotic arm.
"This is an extremely busy day," Paul Dye, Atlantis' lead shuttle flight director, said during a status briefing here at NASA's Johnson Space Center. "It's one of the busiest days I've ever put together on paper for a mission, and they're handling it very well."
Typically, a shuttle docking is the highlight of a day's work, but the Atlantis astronauts still had more on their plate after joining Expedition 13 commander Pavel Vinogradov and flight engineers Jeffrey Williams and Thomas Reiter aboard the ISS.
"This crew has been training longer than any crew I've ever worked with and they're very flexible," Dye said of the STS-115 astronauts' schedule.
Burbank and shuttle pilot Chris Ferguson eased the 35,000-pound (15,875-kilogram) Port 3/Port 4 trusses out of Atlantis' payload bay, at one time wrangling with clearances of just inches between the station segments and orbiter hardware, shuttle officials said.
By 10:30 EDT (1430 GMT), the two joined truss segments were parked at the end of the space station's nearly 57-foot (17-meter) robotic arm under the direction of MacLean and Williams. MacLean, a veteran shuttle flyer representing the Canadian Space Agency, is the first from his country ever to control the space station's Canadian-built robotic arm.
The robotic arm handoff has since become a standard training exercise for astronauts, Dye said.
"We've done this P3/P4 unberth and handoff hundreds of times in simulations, over and over and over," Dye told reporters while watching the orbital arm ballet on NASA TV. "It's wonderful to see it happening for real."
With the P3/P4 truss segments now hanging in space, the thermal clock is ticking to attach them to the end of the Port 1 (P1) truss in a Tuesday spacewalk, the first of three extravehicular activities (EVA) planned for the STS-115 mission.
MacLean and Williams positioned the new ISS hardware to keep it warm overnight, but the segments must be connected to vital power and heaters - to be attached in tomorrow's 6.5-hour spacewalk - before it can double the station's power grid capability.
The trusses will be connected to the end of P1 via four motorized bolts before STS-115 spacewalkers Joseph Tanner and Heidemarie Stefanyshyn-Piper step outside the ISS to attach the vital cables. Only three bolts are required for a good connection, and the astronauts can manually drive the bolts in as well - which would add at least 45 minutes to the spacewalk schedule - should the automatic system fail, Dye said.
"We want to get the umbilicals hooked up on the EVA tomorrow in order to make sure that we can keep that thing alive and in good shape," Dye said of Tuesday's planned spacewalk. "We've got margin to that, of course, it won't be a disaster if we don't make it there. But it is going to be a very aggressive day."
NASA's STS-115 mission is the agency's first dedicated ISS construction flight since late 2002. Orbital construction stalled pending NASA's recovery from the 2003 Columbia accident. The 11-day mission will deliver the second of four planned U.S.-built solar arrays to the station.
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