Spacewalking Astronaut Found Metal Shards On Joint
scrapped a plan to test a shuttle heat shield repair technique
so astronauts have time to study a critical part of the
International Space Station's power system that is now in question,
NASA said Monday.
As a result, NASA will delay the shuttle Discovery's departure
from the station to November 5 -- giving the combined STS-120 and
Expedition 16 crews a day off between the fourth and fifth planned
spacewalks, and also cutting a day out of the already slim six-day
window of opportunity for the next shuttle mission.
That mission is targeted for launch on December 6, according to
Reuters. The shuttle Atlantis will fly the long-awaited Columbus
laboratory to the station.
For almost two months, NASA has been aware of a potential
problem with one of the station's massive rotary joints that spin
the outpost's solar wing panels so they can track the sun and
Astronaut Dan Tani was dispatched on Sunday to investigate the
problem during a space walk. He found shards of metal scrapings
prevalent throughout the joint. "I was quite sure there was
something anomalous with the mechanism," Tani said Monday during an
Tani collected some samples to return to Earth for analysis...
but space station commander Peggy Whitson, a biochemist, conducted
an experiment on Monday and discovered the metal bits contained
NASA had hoped the debris was from the devices aluminum-lined
thermal covers from outside the joint. Engineers will now be
looking at the internal parts of the rotary joint itself.
Mission managers decided to lock the affected solar panels in
place to avoid working the rotary joint to prevent further damage.
This procedure cuts the amount of power the station can produce, a
situation that must be corrected before Japan's science laboratory,
Kilo, is launched next year.
"We can move it around, but without knowing what the problem is
there is the risk that we could do more damage," Whitson said.
The issue will supercede practicing a shuttle heat shield
repair technique, one of several safety upgrades NASA developed
after the 2003 Columbia disaster. Instead, space walkers will
spend the fourth outing of the mission pulling off the rest of the
troubled joint's thermal covers to see if the damage is
In addition, space walkers Scott Parazynski and Doug Wheelock,
who are scheduled to leave the space station's airlock early
Tuesday for the mission's third space walk, will inspect the
station's healthy solar power panel joint to compare it with its
The primary goal of the October 30 outing is to move a third
pair of solar wing panels to a new position on the far end of the
The folded-up wings must then be unfurled, a maneuver that has
become more critical in light of the power shortfall caused by the
Discovery's astronauts arrived at the station on October 25, for
what was planned to be a 10-day stay. With the mission extension,
Discovery's return to Earth has been postponed to November 7.
(Images courtesy of NASA and NASA TV)