Updated at 3:58 p.m.
ET
HOUSTON - NASA added a day to space shuttle
Discovery's STS-120 construction flight, mission managers said today. The
decision was made to better scope out a grit-filled joint on the International
Space Station's (ISS) backbone-like truss, but the extension could delay an
upcoming shuttle launch in early December.
The changes were
speculative earlier today, but STS-120 capsule communicator Tony Antonelli told
the crew before they went to bed that mission planners had officially approved
them. Mike Suffredini, NASA's ISS program manager, said that the launch of
shuttle Atlantis could shift from Dec. 6 to Dec. 7 because of the changes.
"We are absolutely
booked," Suffredini said of the schedule leading up to Atlantis' launch.
"But if all goes well, we'll get that day back."
The upcoming STS-122
mission set to launch with Atlantis will ferry the European Space Agency's Columbus laboratory module into orbit and attach it to the new
Harmony module.
Particular problem
NASA made the move almost
two days after spacewalker Dan Tani discovered metallic shavings in a starboard
rotating joint, which orients the space station's solar arrays toward the Sun.
Early Sunday morning, Tani pried off a thermal covers on the solar alpha rotary
joint, or SARJ, and took a peek inside.
"I've never seen (a
SARJ) in a pristine state, but it was obvious that there was
significant debris, sort of a dust in there," Tani said during a
conference with the STS-120 and space station crews as they floated in
zero-gravity. Tani sampled the grit with a piece of tape that engineers will
examine when Discovery returns to Earth in early November.
"It's not aluminized
Mylar and it's not from the covers," Suffredini said of the shavings,
which space station commander Peggy Whitson found to be iron-containing earlier
today. "So that would tell you that, perhaps, it's some of the steel from
the bearings or the race (wheel) or some other area."
If such components are
creating the metallic grime, mission managers think the 10-foot (3-meter)
diameter rotating joint might be damaged. Until they know for certain, ground
controllers have halted the still fully operational starboard device.
The disabled component
now limits the space station's power-gathering abilities, but Suffredini said
there should be no issues in having enough power to attach the Columbus module in December.
Extended EVA
The fourth EVA, or
extravehicular activity, that was slated for Nov. 1 had spacewalkers testing a "goo-gun"
repair method for the space shuttle's thermally shielded belly—NASA,
however, scrapped the short spacewalk and replaced it with 6-plus-hour venture
to better inspect the rotating joint.
"It's a bit of
exploratory surgery," Suffredini said of 22 thermal blankets that
spacewalkers will need to remove from worrisome
starboard joint.
Mission managers said that spacewalking
astronauts need the extra day to rest between the fourth and fifth exhausting
EVAs of the space shuttle mission. As for the thermal repair experiments, ISS
flight director Rick LaBrode said equipment would be left on board the space
station for the STS-122 to test.
"The priority is
still the lowest on our mission," LaBrode said of the new repair test,
called the tile repair ablator dispenser (T-RAD).
Busy spacewalk ahead
While mission managers
debated whether or not to change the fourth spacewalk and tack on an extra day,
spacewalkers Scott
Parazynski and Doug Wheelock began preparing for the third EVA of the
mission, which begins at 5:28 a.m. EDT (0928 GMT) on Tuesday.
Earlier today, ground
controllers and astronauts on board the space station transferred the
35,000-pound (15,875-kilogram) Port 6 (P6) truss segment from space shuttle
Discovery's robotic arm to the ISS robotic arm, setting the stage for the
spacewalk. With help from crew inside of the space station, Parazynski and
Wheelock will latch on the massive Port 6 (P6) solar array truss to its
permanent home on the Port 5 (P5) truss.
Parazynski, however, will
spend about 40 minutes after its reattachment to scope out the supposedly
pristine rotary joint on the Port 1 (P1) truss.
"Whatever we see on
P1 should be considered normal, whatever normal means," Suffredini.
"We're trying to find out what a normal joint should look like. This joint
has worked fine."
Pamela Melroy, the
STS-120 commander affectionately known as "Pambo" by her crew, said
the extra day in space is not a surprise and welcomes the change.
"Fortunately, we've
already talked about this possibility before we flew," Melroy said, noting
the complexity of the mission at hand. "It's another day in space docked
to the space station, and that's great."
NASA is broadcasting
Discovery's STS-120 mission operations live on NASA TV. Click here for mission updates
and NASA TV from SPACE.com.
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