HOUSTON - The first new addition to the International Space
Station (ISS) in more than three years is safely attached to the orbital
laboratory thanks to two spacewalking astronauts and some precision robotic arm
work.
Atlantis shuttle astronauts Joseph
Tanner and Heidemarie Stefanyshyn-Piper
outfitted the space station's new $372
million truss segments and solar arrays with vital power and data cables
during the first of three
spacewalks of NASA's STS-115 mission.
"Let's get this show going," Tanner
said to kick off the six-hour, 26-minute spacewalk.
The successful spacewalk marks the
end of a long wait for the station's new Port
3/Port 4 (P3/P4) trusses, which were delivered to NASA's Kennedy Space Center spaceport in 2000. Slated to launch
in early 2003, the segments and their new solar arrays were delayed following
the Columbia accident that
year, station managers said.
"It's kind of like seeing your kids
grow up," Kirk Shireman, NASA's deputy space station
manager, said of the 45.3-foot (13-meter) integrated P3/P4 segment Monday.
"We've been babying it and protecting it and improving it."
NASA plans 14 more shuttle missions
to complete construction of the ISS by 2010, when the shuttles will be retired.
Always ahead of schedule, Tanner and
Stefanyshyn-Piper appeared to breeze through their
orbital construction tasks, ultimately completing their work early enough to
get a head start on other truss chores slated for their STS-115 crewmates Daniel
Burbank and Steven
MacLean on Wednesday.
Only an errant spring, bolt and
washer, which escaped from Tanner as he removed a launch lock from truss
equipment, appeared to mar the spacewalk.
"It was breezing across the surface
of structure," said Tanner of bolt and spring to mission controllers, who will
track the lost items to make sure they don't pose a threat to station hardware.
"I suspect this might happen again...those springs are pretty nippy."
Swift spacewalkers
Tuesday's ISS construction work
began even before Tanner and Stefanyshyn-Piper
stepped outside the station's Quest airlock at 5:17 a.m. EDT (0917 GMT).
The two spacewalkers waited
patiently inside the airlock as MacLean and ISS Expedition 13
flight engineer Jeffrey
Williams maneuvered the 35,000-pound (15,875-kilogram) P3/P4
truss segments to a berth at the end of the station's Port 1 (P1) truss.
The connections between the two
trusses were never tested together on Earth, but three of four motorized bolts
flawlessly mated the space station pieces in place, clearing Tanner and Stefanyshyn-Piper to begin their spacewalk. A fourth bolt
was also driven in as planned.
"Look at that sunrise coming, Heide," said Tanner, who made his sixth spacewalk during
today's work.
"Oh wow," replied Stefanyshyn-Piper, who made her spacewalk debut today. "That's
pretty."
Tanner connected a series of power
and data cables to support the P3/P4 electronics, and then joined Stefanyshyn-Piper to unlock and position the boxes and
cylindrical canisters containing the folded up solar arrays and their pop-up
masts.
The solar arrays are scheduled to be
unfurled on Thursday.
Tanner and Stefanyshyn-Piper
also removed restraints and primed motors to drive the Solar
Alpha Rotary Joint (SARJ), a wheel-like joint that will rotate the massive
P4 truss - and future segments - 360 degrees so their solar arrays can track
the Sun.
"I'd just like to thank everyone for
my first EVA," Stefanyshyn-Piper said of today's
spacewalk. "It was great."
ISS spacecraft communicator and NASA
astronaut Pam Melroy told the spacewalkers that they
"did a phenomenal job and set the bar amazingly high for the rest of assembly."
More to come
Shireman told SPACE.com that he and
his team won't rest easy until after the solar arrays are unfurled to their
full 240-foot (73-meter) wingspan on Thursday.
In 2000, when Tanner and NASA
astronaut Carlos Noriega helped install the
first U.S. power plant at the ISS during their STS-97
mission, the solar panels stuck together as they unfolded due to a
phenomenon later dubbed "stiction." Engineers found that they could work around
the glitch by deploying the solar arrays in stages using a high tension mode,
which allows the panels to warm up and avoid sticking to one another.
During today's spacewalk, mission
controllers radioed the STS-115 crew to say that extra inspections
of their shuttle Atlantis' heat shield will
not be required while they are docked at the ISS. The decision, announced
late Monday here at NASA's Johnson Space Center, clears the way from Wednesday's
spacewalk by Burbank and MacLean.
"That's wonderful, that means we've
got a good vehicle," Tanner said, while he and Stefanyshyn-Piper
worked 218 statute miles (350 kilometers) above Earth.
Mission controllers woke the STS-115
crew at 11:15 p.m. EDT Monday night (0315 Sept. 12 GMT) to the sound of
Ukrainian song chosen for Stefanyshyn-Piper, whose
father is from Ukraine.
"It was written by Taras Shevchenko, a Ukrainian
poet, and he writes to remind everyone to learn and to read as much as you can,
and to teach others and learn from others," Stefanyshyn-Piper
said. "And I think being up here on the ISS, that's exactly what we're doing."
Today's spacewalk marked the 70th to
support the ISS, the 42nd staged from the outpost itself, and the 23rd to
originate from the U.S.-built Quest airlock.
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