HOUSTON — Two spacewalking astronauts
reattached a massive solar power plant of the International Space Station (ISS)
today, and inspected gears that orient its wing-like arrays toward the Sun.
But during
NASA mission control's unfurling of wing-like solar arrays on the relocated power
plant, the right wing of the 4B solar
array crinkled and tore on one edge. The array opposite of 4B, known as 2B,
deployed without incident prior to 4B's unfurling.
Astronauts
aboard the space station were watching mission control's unfurling of the
arrays, when ISS commander Peggy Whitson told mission control to abort the
operation. The massive station piece with attached arrays was successfully
reattached during today's spacewalk, which began at 4:45 a.m. EDT (0845 GMT)
and ended at 11:53 a.m. EDT (1553 GMT).
"We
just saw the tear and stopped," Whitson told ground controller and shuttle
capsule communicator Kevin Ford after the tear was noticed. She added that the
astronauts aboard the orbital laboratory could not clearly see the solar wing
during part of the deployment because the sun's glare blocked their view.
"It
looks like the damage appeared fairly suddenly," said space shuttle
Discovery commander Pamela Melroy, who arrived with her STS-120 crew on
Oct. 25.
Mission controllers said about 25 meters
(82 feet) of the 35-meter (115-foot) electricity-generating array was deployed
before the unfurling was halted.
It is
uncertain at this time how the tear will impact the solar wing's energy
gathering ability, which the space station's successful construction partly
depends on. Astronauts have begun easing tension on the array to see how the
damaged area responds.
Successful
spacewalk
Prior to
accidental damage to the solar wing, however, orbital construction workers Scott
Parazynski and Doug Wheelock successfully completed today's spacewalk,
which lasted seven hours and eight minutes. Parazynski and Wheelock reattached
the 35,000-pound (15,875-kilogram) Port 6 (P6) solar truss segment to the end
of the orbital laboratory from which the solar arrays were later deployed.
After the
behemoth truss segment was attached, Parazynski scoped out a set of gears that
orient the station's solar panels toward the Sun. The port-side gears are
working normally, but NASA engineers want to compare them to a similar yet misbehaving
mechanism at the other end of the space station.
"I
have a happy story so far," Parazynski said as he looked under a solar
cover to the paddle-like joint containing the gears. "They look like
they're brand new machines."
"It's
going to help a lot with the diagnosis we've been making," said mission
controllers here at Johnson Space Center as Parazynski relayed video images of
the gears to Earth.
The report
is a stark contrast that made by space shuttle Discovery astronaut Dan Tani,
who found unusual metallic grit coating the gears of the 10-foot (3-meter)
diameter starboard joint.
"It
looked like a black dust of metallic shavings or filings," Tani said of
the grit during an in-flight interview Monday. "It was unmistakable that
it should not be there."
The
unwelcome discovery prompted officials to extend
the mission by one day, which will make room to replace a short spacewalk
with a long, more complete check-out of the suspect starboard joint on
Thursday.
Today
marked the third of five record-tying extravehicular activities, or EVAs,
planned during the STS-120's 15-day mission. It was Parazynski's sixth EVA and
Wheelock's second.
The space
shuttle Discovery is scheduled to land on Nov. 7 at Kennedy Space Center in Cape Canaveral, Fla. The spaceship will ferry ISS crewmember Clayton Anderson
back to Earth, leaving Tani to take his place as a member of the Expedition 16
crew led by Whitson.
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