Shuttle Mission Extended One Day
NASA has extended the current shuttle mission by one day to allow additional inspections of the malfunctioning rotary joint on the International Space Station.
The work will delay Discovery's departure from the station to Monday from Sunday, a postponement that NASA said could carve a day out of the already slim six-day launch window for the next mission, when the shuttle Atlantis will fly the long-awaited Columbus laboratory to the station. That mission is targeted for launch on December 6.
For nearly 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 generate power.
But when spacewalker Dan Tani was dispatched on Sunday to investigate the problem during a spacewalk, he found shards of metal scrapings prevalent throughout the joint.
"I was quite sure there was something anomalous with the mechanism," Tani said on Monday during an in-flight interview.
He collected samples to return to Earth for analysis, but space station commander Peggy Whitson, a biochemist, conducted a preliminary experiment on Monday and discovered that the metal bits contained iron.
That was not good news. NASA had hoped the debris was coming from outside the joint, such as from one of the device's aluminum-lined thermal covers. Now engineers will be looking at parts of the rotary joint itself.
Not a good thing. The NASA website elaborates:
After analyzing photos of debris found inside the station’s starboard Solar Alpha Rotary Joint, mission managers decided to devote the mission’s fourth spacewalk Thursday to further inspection of the joint.
As a precursor to the additional rotary joint inspection spacewalk, Tuesday’s spacewalk by Mission Specialists Scott Parazynski and Doug Wheelock will include a short task to inspect the port rotary joint to provide comparison data to station managers who will spend the night developing procedures for the fourth spacewalk. All other tasks for the third spacewalk remain as trained with the focus being on installation of the P6 truss and solar array pair to its permanent location outboard of the port truss.
The crews completed final preparations for the P6 truss installation and continued outfitting and activation of avionics and systems racks inside the Harmony Node. Despite the shutdown of the Carbon Dioxide Removal Assembly in the U.S. Destiny laboratory, work continues as normal with no interruption to operations with other means of carbon dioxide scrubbing equipment on board.
Something is grinding in that joint, obviously.
By NortonPete, Monday, 29 October , 2007 @ 8:07 pm
They have had suspicions due to vibrations recorded in the movement of the solar panel. Bad. Bad that there are recordable vibrations. Something is grinding in that joint, you are correct.. They will find that some Earth origin debris was left in the gearbox. Apparently they could rebuild the entire joint with parts that are already in space. But the time cost would be high.