CAPE CANAVERAL, Fla. -- For the second straight day, a pair of highflying hardhats will labor outside the International Space Station this morning to prepare a $372 million set of solar arrays for operation.
Space walkers Dan Burbank and Steve MacLean will have a tough act to follow during a planned 6 1/2 -hour excursion set to begin at 5:15 a.m. Yesterday, shuttle Atlantis crewmates Joe Tanner and Heide Stefanyshyn-Piper breezed through one of the most complex space walks ever with relative ease.
"Joe and Heide, you did a phenomenal job," astronaut Pam Melroy radioed from Mission Control as the space walk ended. "It set the bar very high for the rest of [the station's] assembly."
"We just did what we were told, Pam," joked Tanner, a veteran of five previous space walks. "It's just the best that we could. That's all we wanted to do. Right, Heide?"
"That's all I wanted to do," Stefanyshyn-Piper replied.
As a result of yesterday's work, Atlantis' astronauts are considerably closer to the big-picture goal of their 11-day mission: successfully jumpstarting the station's long-delayed construction. A 35,000-pound truss housing the solar arrays now is bolted to the station with vital power and data connections.
Burbank and MacLean will try to build on that accomplishment this morning by releasing 14 launch locks and six other restraints from a wheel-like rotating structure that holds the power-producing arrays. The work will allow the solar panels to move and track the sun to more effectively generate electricity.
Once that work is complete, flight controllers will begin the process of unfurling the 240-foot panels from the boxes they have been stored in for more than five years. The arrays are expected to eventually double the station's power supply.
Yesterday's space walk was a crucial step toward turning on that power.
Tanner and Stefanyshyn-Piper connected 13 data and power cables essential to the arrays' activation. The astronauts also rotated into position the boxes holding the panels, removed several launch restraints and had enough time left to perform several "get ahead" tasks originally planned for today's space walk.
It was during the get-ahead work that the day's only glitch occurred; Tanner lost a bolt, washer and spring from a pair of launch restraints he was removing.
He could not say for sure where the floating hardware disappeared to. In the unlikely event it entered the truss, there was concern the pieces might cause problems inside.
"I don't see any way it could have gotten in," Tanner radioed after a brief inspection. "I don't see it anywhere."
Tanner described the event again after the space walk ended for flight controllers, who replied that it was no big deal.
"We sure appreciate all of the extra detail," Mission Control said, "but we don't think it's going to be a problem."
NASA officials echoed that assertion later in the day after further analysis. The shuttle's mission management team also cleared Atlantis' heat shielding for next week's return home. Engineers studying data from an inspection in orbit and photographs have determined there was no problem from launch debris.
Michael Cabbage writes for the Orlando Sentinel.