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STS-126: The programs

In advance of shuttle Endeavour's STS-126 mission to the station, managers from both programs discuss the flight.

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STS-126: The mission

A detailed preview of Endeavour's mission to deliver expanded crew accommodations to the station is provided in this briefing.

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STS-126: Spacewalks

Four spacewalks are planned during Endeavour's STS-126 mission to the station.

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STS-126: The Crew

The Endeavour astronauts, led by commander Chris Ferguson, meet the press in the traditional pre-flight news conference.

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Shuttle rollaround

Space shuttle Endeavour switched launch pads on Oct. 23, traveling from pad 39B to pad 39A.

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Two shuttles sighted

Stunning aerial views of shuttles Atlantis and Endeavour perched atop launch pads 39A and 39B on Sept. 20.

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Endeavour to the VAB

For its role as a rescue craft during the Hubble servicing mission and the scheduled November logistics run to the space station, Endeavour is moved to the Vehicle Assembly Building.

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Today's spacewalk to finish work on paddle wheel joint
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: November 22, 2008

Astronauts Heidemarie Stefanyshyn-Piper and Stephen Bowen are gearing up for a grueling seven-hour spacewalk today to finish cleaning and lubricating the international space station's damaged right side solar array rotary joint. Engineers in Houston, meanwhile, are continuing tests to troubleshoot problems with the station's new urine recycling system.

Today's spacewalk, the 117th devoted to station assembly and maintenance since construction and the third of four planned by Endeavour's crew, is scheduled to begin around 1:45 p.m.

While the work outside is going on, managers, engineers and flight controllers at the Johnson Space Center in Houston will be assessing test results and plans for coaxing the station's urine processor into normal operation. An operational water recycling system is crucial to NASA's plans for increasing station crew size from three to six next May.

The shuttle Endeavour's mission could be extended one day to give engineers more time to resolve the problem and collect samples of processed urine for return to Earth. As of this writing, however, it's not yet clear whether an additional day would be sufficient to resolve the problem with the urine processor's centrifuge motor.

Flight controllers activated the processor Friday after troubleshooting an alarm that halted operations the day before. The UPA ran normally for two hours, but then shut down. The motor in the centrifuge of the UPA's vacuum distillation system began slowing down while drawing more power. Telemetry indicated a hardware problem as opposed to a software glitch.

The processor was re-activated late Friday and briefly operated to collect additional data. It was re-started again this morning, around 9:15 a.m.

The astronauts do not have a spare distillation unit on board. If a replacement is required, NASA's plan to increase crew size from three to six next May would have to be put on hold until a new unit could be launched and installed. The next shuttle mission is scheduled for launch in February, but it's not known if a new distillation unit could be ready by then.

Even if a new unit could be ready by then, three months of testing and water analysis would still be required before any astronauts would be allowed to sample recycled water.

But a centrifuge replacement is a worst-case scenario and engineers remain hopeful they can get the water recycling system up and running.

"The two main units we've been working on, the water processing assemby and the urine processing assembly, are in different states," station flight director Brian Smith said early today. "The water processing assembly is doing well and it's currently running right now and processing condensate. The urine processing assembly's had a couple of hiccups since we tried to activate it a couple of days ago. It's currently not running.

"There was a problem yesterday that caused it to shut down. The problem, we believe, is in a sub unit called the distillation assembly. The centrifuge is in that assembly and we saw an unusual signature related to the speed of the motor of that centrifuge as well as the current driving it. We saw the speed go down and the current go up. That sometimes is indicative of some kind of blockage of the spinning motor.

"But we really haven't nailed down the exact root cause yet," Smith said. "We did conduct a test overnight where we brought the unit back up and we ran it again and collected some more data and that data is currently being reviewed by the engineers. We won't do anything else until that data is reviewed and we get better understanding of what's going on.

"As far as how that impacts our goals for the water recovery system, of course we wanted to take samples and bring those back home and we are still on track to do that. The original plan was for the water recovery system to process both urine and condensate, collect that together and run it through the water processing assembly to produce water that we could then sample. We're not going to get the contribution from the urine processing assembly that we had planned for by this flight day. But we've been able to come up with a plan to make up for that by generating extra condensate."

NASA's Mission Management Team will meet later today to discuss the schedule and, presumably, whether to extend Endeavour's mission.

Stefanyshyn-Piper and Bowen, meanwhile, are preparing for a seven-hour spacewalk to complete the cleaning and lubrication of the station's right-side solar alpha rotary joint, or SARJ. The station is equipped with two SARJ joints to rotate outboard solar arrays like giant paddle wheels to track the sun as the lab complex orbits the Earth.

The starboard SARJ has suffered extensive damage and degradation due to a lubrication breakdown. The joint's 10-foot-wide drive gear is held in place by 12 trundle bearing assemblies featuring pressure-loaded rollers that grip the toothed gear on three faces, or bearing races. Two of those, known as the datum-A surface and the inner canted surface, are in good shape. But the surface of the third race ring, the outer canted surface, has been ground up by excessive friction, producing extensive metallic debris.

To reduce rolling friction and minimize additional damage to the outer canted surface, the Endeavour astronauts are replacing 11 of the joint's 12 trundle bearings - one was replaced on an earlier mission - cleaning the race ring with scrapers and grease-impregnated wipes to capture debris and, in the process, applying a fresh layer of lubrication.

During today's spacewalk, Stefanyshyn-Piper and Bowen will attempt to remove and replace six trundle bearing assemblies, or TBAs, to complete the bearing swap outs.

"It's going to be challenging," Stefanyshyn-Piper said Friday. "We have a lot of work to do, still a lot of trundle bearing assemblies to change out and a lot of the race ring to clean. ... Steve and I will be very, very busy out there."

During the first spacewalk Tuesday, Stefanyshyn-Piper lost a $100,000 tool bag overboard. Two of the crew's grease guns were lost, forcing the astronauts to improvise. The original plan called for the spacewalkers to remove a TBA and then lay a bead of lubricant down on the outer canted surface with a grease gun. The grease was intended to capture debris as the astronauts chipped away ground-on fragments with a scraper tool.

Because of the lost grease guns, Stefanyshyn-Piper used a different technique in her second spacewalk Thursday, using grease-impregnated wipes to provide the lubrication needed to capture scraped-off debris. Mission managers later approved the use of a heat-shield repair grease gun if necessary, but Stefanyshyn-Piper said she preferred to press ahead with the wipes instead.

"I think at this point, having looked at both the NOAX (heat-shield repair) gun and also having two EVAs under my belt so far, I think the greased wipes seems to be the most practicable way to go," she said. "The wipes do lay down quite a bit of grease on the surface and it's sufficient grease to scrape up the debris that's there. It requires a little bit more meticulous work because you don't have quite as much grease there, but it is sufficient and you can get by. That's the way we're going to press going into EVA-3. Definitely, having two EVAs, I've learned a lot of things, I've changed my techniques ... so I'm ready to go into EVA-3 and get going."

If the spacewalkers get all the bearings changed out, flight controllers will conduct a test overnight, putting the starboard SARJ in "auto-track" mode for two full orbits. Sensors will measure vibration levels and motor drive currents to determine if the cleaning and lubrication reduced stress on the joint. The test is planned for 3:40 a.m. Sunday,.

The test is designed "to see if the cleaning and lubrication had any noticeable effect and we'll have sensors programmed to record vibrations during the time of the rotation and we'll also have a video camera trained on the joint itself," Smith said.

"In the past, we have been able to notice vibrations as the joint is moving so we'll look for that in the video and we'll also be looking at the current in the telemetry to see what the signatures there look like. Now, if we don't get everything done today on EVA-3, then we'll have to readjust whether it makes sense to perform that test overnight. You certainly don't want to rotate that solar alpha rotary joint if you haven't gotten all the cleaning done. ... So whether or not we do that test tonight depends on the results from the spacewalk today."

Here is an updated timeline of today's activity (in EST and mission elapsed time; includes revision H of the NASA television schedule):


EST........DD...HH...MM...EVENT

08:55 AM...07...13...00...Crew wakeup
09:30 AM...07...13...35...EVA-3: 14.7 psi repress/hygiene break
10:15 AM...07...14...20...EVA-3: Airlock depress to 10.2 psi
10:40 AM...07...14...45...EVA-3: Campout EVA preps
11:50 AM...07...15...55...Cargo module transfers resume
12:10 PM...07...16...15...EVA-3: Spacesuit purge
12:25 PM...07...16...30...EVA-3: Spacesuit prebreathe
01:15 PM...07...17...20...EVA-3: Crew lock depressurization
01:45 PM...07...17...50...EVA-3: Spacesuits to battery power
01:50 PM...07...17...55...EVA-3: Airlock egress
02:05 PM...07...18...10...SDRM transfer
02:05 PM...07...18...10...EVA-3: Setup
02:15 PM...07...18...20...EVA-3: SARJ cleaning and TBA R&R
04:15 PM...07...20...20...ISS: Crew meal
05:15 PM...07...21...20...ISS: Potable water dispenser work
08:15 PM...08...00...20...EVA-3: Cleanup and ingress
08:45 PM...08...00...50...EVA-3: Airlock repressurization
08:55 PM...08...01...00...Spacesuit servicing
10:10 PM...08...02...15...Evening planning conference
10:30 PM...08...02...35...Mission status briering on NASA TV

11/23/08
12:25 AM...08...04...30...ISS crew sleep begins
12:55 AM...08...05...00...STS crew sleep begins
01:00 AM...08...05...05...Flight day 9 highlights
03:40 AM...08...07...45...Starboard SARJ auto-track test
07:30 AM...08...11...35...Flight director update
08:30 AM...08...12...35...HD flight day 9 highlights
08:55 AM...08...13...00...Crew wakeup

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: WALKTHROUGH OF SPACEWALK NO. 3 PLAN PLAY
VIDEO: SATURDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 8 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: JOINT CREW IN-FLIGHT NEWS CONFERENCE PLAY
VIDEO: FRIDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: PROTON ROCKET ROLLS OUT TO THE PAD PLAY
VIDEO: LAUNCH OF THE ZARYA CONTROL MODULE PLAY
VIDEO: POST-LAUNCH COMMENTS BY NASA AND RSA PLAY
VIDEO: SHUTTLE AND STATION COMMANDERS MARK ANNIVERSARY PLAY

VIDEO: FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: THURSDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: MAINTENANCE PERFORMED ON STATION'S ARM PLAY
VIDEO: SPACEWALKERS PULL SECOND RAIL CART FREE PLAY
VIDEO: FIRST CART REMOVED FROM STATION RAILS PLAY
VIDEO: THURSDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: WALKTHROUGH OF SPACEWALK NO. 2 PLAN PLAY
VIDEO: FLIGHT DIRECTOR'S SUMMARY OF FLIGHT DAY 7 PLAY

VIDEO: LAUNCH CAMERA REPLAYS
VIDEO: FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: AP, MINNEAPOLIS AND BOSTON INTERVIEWS WITH CREW PLAY
VIDEO: WEDNESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: RIDE ALONG WITH ASTRONAUTS "RACK-CAM" PLAY
VIDEO: COMBUSTION SCIENCE HARDWARE MOVED INTO STATION PLAY
VIDEO: AIRLOCK CAMCORDER FOOTAGE AFTER SPACEWALK PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: EVA NO. 1 CONCLUDES PLAY
VIDEO: SOLAR ALPHA ROTARY JOINT REPAIRS BEGIN PLAY
VIDEO: TOOL BAG ACCIDENTALLY FLOATS AWAY PLAY
VIDEO: GREASE GUN SPILL MAKES MESS IN TOOL CARRIER PLAY
VIDEO: SPARE FLEX HOSE COUPLER DELIVERED TO STATION PLAY
VIDEO: EMPTY NITROGEN TANK MOVED FROM STATION TO SHUTTLE PLAY
VIDEO: TUESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: SHOW-AND-TELL OF SOLAR ALPHA ROTARY JOINT WORK PLAY
VIDEO: WALKTHROUGH OF SPACEWALK NO. 1 PLAN PLAY
VIDEO: NARRATED ANIMATION OF SPACEWALK SWAPOUT PLAY
VIDEO: FLIGHT DIRECTOR'S SUMMARY OF FLIGHT DAY 5 PLAY

VIDEO: FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: CREW OPENS HATCH AND ENTERS LEONARDO PLAY
VIDEO: ATLANTA AND BOSTON TV STATIONS INTERVIEW CREW PLAY
VIDEO: MONDAY'S MISSION MANAGEMENT TEAM UPDATE PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: LEONARDO MODULE SUCCESSFULLY MOUNTED TO STATION PLAY
VIDEO: MONDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: PREVIEW ANIMATION OF LEONARDO MODULE ATTACHMENT PLAY
VIDEO: SUMMARY OF CARGO BEING DELIVERED TO SPACE STATION PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: SPACE SHUTTLE ENDEAVOUR DOCKS TO SPACE STATION PLAY
VIDEO: ENDEAVOUR PERFORMS THE 360-DEGREE BACKFLIP PLAY
VIDEO: VIEWS OF THE SHUTTLE APPROACHING FROM BELOW PLAY
VIDEO: FLIGHT DIRECTOR'S SUMMARY OF FLIGHT DAY 3 PLAY
VIDEO: PREVIEW ANIMATION OF RENDEZVOUS AND DOCKING PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: SATURDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SATURDAY'S MISSION MANAGEMENT TEAM UPDATE PLAY
VIDEO: FLIGHT DIRECTOR'S SUMMARY OF FLIGHT DAY 2 PLAY
VIDEO: PREVIEW ANIMATION OF HEAT SHIELD INSPECTIONS PLAY
VIDEO: NARRATED TOUR OF ENDEAVOUR'S PAYLOAD BAY PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: SPACE SHUTTLE ENDEAVOUR BLASTS OFF! PLAY
VIDEO: SPACEFLIGHT NOW'S LAUNCH PAD CAMERA PLAY
VIDEO: THE FULL STS-126 LAUNCH EXPERIENCE PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: POST-LAUNCH NEWS BRIEFING PLAY

VIDEO: FINAL PRE-LAUNCH POLLS GIVE "GO" FOR LIFTOFF PLAY
VIDEO: SHUTTLE'S CREW MODULE HATCH CLOSED FOR FLIGHT PLAY
VIDEO: MISSION SPECIALIST DON PETTIT BOARDS PLAY
VIDEO: MISSION SPECIALIST SHANE KIMBROUGH BOARDS PLAY
VIDEO: PILOT ERIC BOE BOARDS ENDEAVOUR PLAY
VIDEO: COMMANDER CHRIS FERGUSON BOARDS ENDEAVOUR PLAY
VIDEO: ASTROVAN TAKES CREW TO LAUNCH PAD 39A PLAY
VIDEO: CREW DEPARTS QUARTERS FOR LAUNCH PAD PLAY
VIDEO: ASTRONAUTS DON SPACESUITS FOR LAUNCH PLAY
VIDEO: NARRATED RECAP OF ENDEAVOUR'S PRE-FLIGHT CAMPAIGN PLAY
VIDEO: NARRATED RECAP OF PAYLOADS' PRE-FLIGHT CAMPAIGN PLAY

VIDEO: PAD 39A SERVICE GANTRY RETRACTED FOR LAUNCH PLAY
VIDEO: THURSDAY'S COUNTDOWN STATUS AND WEATHER UPDATE PLAY
VIDEO: WEDNESDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: ENDEAVOUR ASTRONAUTS ARRIVE FOR LAUNCH PLAY | HI-DEF
VIDEO: TUESDAY'S COUNTDOWN STATUS AND WEATHER UPDATE PLAY

VIDEO: STATION ASTRONAUTS PREPARE FOR SHUTTLE ARRIVAL PLAY
VIDEO: ENDEAVOUR'S PAYLOADS READIED FOR TREK TO SPACE PLAY

VIDEO: UPDATE ON SHUTTLE AND STATION PROGRAMS PLAY
VIDEO: STS-126 MISSION OVERVIEW PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: INTERVIEW WITH COMMANDER CHRIS FERGUSON PLAY
VIDEO: INTERVIEW WITH PILOT ERIC BOE PLAY
VIDEO: INTERVIEW WITH MS1 HEIDEMARIE PIPER PLAY
VIDEO: INTERVIEW WITH MS2 STEPHEN BOWEN PLAY
VIDEO: INTERVIEW WITH MS3 DON PETITT PLAY
VIDEO: INTERVIEW WITH MS4 SHANE KIMBROUGH PLAY
VIDEO: INTERVIEW WITH MS5 SANDY MAGNUS PLAY

VIDEO: INTERVIEW WITH SPACE STATION'S EXPEDITION 17 CREW PLAY

VIDEO: ENDEAVOUR COMMANDER AND PILOT PRACTICE LANDINGS PLAY

VIDEO: ISS PROGRAM MANAGER UPDATES SOYUZ INVESTIGATION PLAY
VIDEO: ISS PROGRAM MANAGER DESCRIBES SARJ REPAIR PLAN PLAY
VIDEO: ISS PROGRAM MANAGER DISCUSSES RADIATOR DAMAGE PLAY
VIDEO: EXPEDITION 18 PRE-FLIGHT MISSION BRIEFING PLAY

VIDEO: AERIAL VIEWS OF ATLANTIS AND ENDEAVOUR PLAY | HI-DEF
VIDEO: ENDEAVOUR AT SUNRISE ON LAUNCH PAD 39B PLAY | HI-DEF
VIDEO: AERIAL VIEWS OF ENDEAVOUR AFTER ROLLOUT PLAY | HI-DEF
VIDEO: ENDEAVOUR ROLLS FROM VAB TO LAUNCH PAD PLAY | HI-DEF
VIDEO: TIME-LAPSE MOVIE OF ARRIVAL AT PAD 39B PLAY
VIDEO: TIME-LAPSE MOVIE OF ENDEAVOUR LEAVING VAB PLAY

VIDEO: SHUTTLE HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: ENDEAVOUR'S DEPARTURE FROM HANGAR PLAY | HI-DEF

VIDEO: TIME-LAPSE MOVIE OF ENDEAVOUR GOING VERTICAL PLAY
VIDEO: TIME-LAPSE MOVIE OF BEING HOISTED OFF TRANSPORTER PLAY
VIDEO: TIME-LAPSE MOVIE OF ENDEAVOUR MOVING TO VAB PLAY
MORE: STS-126 VIDEO COVERAGE
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