The Discovery astronauts unlimbered the Kibo laboratory module's Japanese robot arm today and prepared spacesuits and equipment for a third and final spacewalk Sunday to collect debris samples from a solar array rotary joint and install a tank of pressurized nitrogen for the space station's ammonia coolant loops.

"Preparations for the third walk are going great," said spacewalker Michael Fossum. "We've got the suits checked out and just about ready to go, all our tools packed up and after a few final procedures reviews, we'll be ready to go out the door tomorrow."

Mission managers early today approved a plan for Fossum collect samples of apparent debris he saw inside the station's left-side solar alpha rotary joint during the crew's second spacewalk Thursday.

The space station is equipped with two SARJ gears, one on either side of the lab's main power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. The right side SARJ has suffered considerable damage to the surfaces of the 10-foot-wide drive gear that are gripped by 12 three-roller trundle bearings.

The left-side SARJ is operating normally, but Fossum spotted buildups of grease during an inspection Thursday. Photographs also indicted small amounts of an unknown material dusting the outer edge of the drive gear.

Engineers believe the grease may be coming from one or more of the trundle bearings the gear rolls through and it may be beneficial in slowing or preventing the sort of surface breakdown that has damaged the right-side gear. In any case, the grease is not thought to be a serious issue.

A senior space station manager said in an email grease had been seen during an earlier inspection during shuttle mission STS-120 in October 2007 as well as during ground testing.

"Pictures after the EVA during (assembly mission) 10A did show us a similar appearance," he said. "The pictures from this EVA are of higher resolution and allow us to more definitively conclude it to be grease from the rollers. This is not unexpected as it was seen during our ground life tests."

The dust-like material was somewhat of a surprise, Fossum said, but it is nothing like the damage and debris seen in the right-side SARJ.

"I don't believe it looks at all like the starboard side," Fossum told a reporter today. "The starboard side definitely has metal shavings that show up and you can see some damage to the metal surface. There's just some things look different on the side we looked at the other day, the port side. It really looks to me like a little bit of grease, which is not a terrible big surprise when you're dealing with a bearing surface.

"But it was not expected. Through the photographs, there might be a little bit of dusting of some other deposits around there so right now, and this plan is changing by the hour, tomorrow we plan to go out with a little bit of special tape and collect some of that dust from around the edge of the bearing. But really, that bearing looks to be in pretty darn good shape."

During today's work aboard the space station, the astronauts continued outfitting and activating the Japanese Kibo lab module and re-establishing connections between Kibo and a smaller logistics module that was mounted atop the new laboratory on Friday.

Japanese astronaut Akihiko Hoshide also moved Kibo's robot arm, which will be used in the future to manipulate externally mounted payloads and experiments, for the first time to give Fossum and Ronald Garan access to launch locks that will be removed during Sunday's spacewalk.

The arm "was too close in the launch configuration to the module itself so that Ron and Mike cannot access those launch locks," Hoshide said in a NASA interview. "So what we're trying to do is to deploy it just a little bit, and that's called the 'initial deploy,' so they can access. We'll have them take off the launch locks and then we'll do a final deploy so that's away from the module and then later in the mission we'll do a checkout of the arm, making sure that the brakes are working correctly and then move it into a storage configuration."

Late today, flight controllers told the astronauts that analysis of about 70 800-millimeter telephoto images of two leading edge wing panels that the crew took Friday showed the reinforced carbon carbon panels were in good shape. The pictures were taken after data from an impact sensors behind the panels showed a spike during final approach to the station Monday.

Hoshide and shuttle commander Mark Kelly will take a call from Japanese Prime Minister Yasuo Fukuda at 7:02 p.m.

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

EDT........DD...HH...MM...EVENT

06/07/08
06:02 AM...06...13...00...Crew wakeup
08:02 AM...06...15...00...ISS daily planning conference
08:52 AM...06...15...50...Shuttle robot arm maneuver
09:02 AM...06...16...00...Airlock preps for EVA-3
09:27 AM...06...16...25...Middeck transfers
09:47 AM...06...16...45...EVA-3: Tools configured
10:27 AM...06...17...25...Kibo robot (JRMS) arm setup
11:17 AM...06...18...15...JRMS hold/release mechanism test
12:17 PM...06...19...15...JRMS initial deploy
01:32 PM...06...20...30...ISS crew meal
02:02 PM...06...21...00...Crew media interviews
02:22 PM...06...21...20...Shuttle crew meal
03:22 PM...06...22...20...Logistics module vestibule outfitting
05:02 PM...07...00...00...Station robot arm maneuver
05:27 PM...07...00...25...EVA-3: Procedures review
07:02 PM...07...02...00...Japanese VIP event
07:30 PM...07...02...28...Mission status briefing on NTV
07:57 PM...07...02...55...EVA-3: Mask pre-breathe/tool config
08:30 PM...07...03...28...VIP event replay with English translation; on NTV
08:42 PM...07...03...40...EVA-3: Airlock depress to 10.2 psi
09:02 PM...07...04...00...ISS crew sleep begins
09:32 PM...07...04...30...STS crew sleep begins
10:00 PM...07...04...58...Daily video highlights reel on NTV

Additional coverage for subscribers:
VIDEO: MEDIA INTERVIEWS WITH SHUTTLE AND ISS CREWS PLAY
VIDEO: KIBO LAB'S ROBOTIC ARM FLEXES FOR FIRST TIME PLAY
VIDEO: NARRATED PREVIEW OF ARM'S FIRST MOVEMENTS PLAY
VIDEO: SATURDAY'S FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING UPWARD PLAY
VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING INBOARD PLAY
VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING DOWNWARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING UPWARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING DOWNWARD PLAY

VIDEO: THE FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW ASKED TO TAKE PHOTOS OF WING PANELS PLAY
VIDEO: JAPANESE LOGISTICS MODULE MOVED TO KIBO LAB'S ROOF PLAY
VIDEO: STATION'S ROBOT ARM GRAPPLES LOGISTICS MODULE PLAY
VIDEO: MEDIA INTERVIEWS WITH SHUTTLE AND ISS COMMANDERS PLAY
VIDEO: FRIDAY'S FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: NARRATED PREVIEW OF LOGISTICS MODULE MOVE PLAY

VIDEO: THE FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: BUZZ LIGHTYEAR TOY ON THE LOOSE IN SPACE PLAY
VIDEO: ASTRONAUTS INVITE VIEWERS TO DINNER PLAY
VIDEO: THURSDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: INSPECTION OF THE PORT-SIDE SOLAR ROTARY JOINT PLAY
VIDEO: FAULTY TV CAMERA REMOVED FROM STATION PORT TRUSS PLAY
VIDEO: THERMAL SLEEVE PLACED ON KIBO TRUNNION PIN PLAY
VIDEO: LAUNCH LOCKS RELEASED ON KIBO'S UPPER PORT PLAY
VIDEO: SPACEWALKERS INSTALL PAIR OF TV CAMERAS ON KIBO PLAY
VIDEO: MIKE FOSSUM EMERGES FROM AIRLOCK FOR EVA NO. 2 PLAY
VIDEO: NARRATED PREVIEW OF SPACEWALK NO. 2 PLAY
VIDEO: THURSDAY'S FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: THE FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: ASTRONAUTS ENTER THE KIBO MODULE FOR FIRST TIME PLAY
VIDEO: CEREMONY BEFORE KIBO HATCH OPENING PLAY

VIDEO: THE FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: KIBO SCIENCE LAB ATTACHED TO THE SPACE STATION PLAY
VIDEO: KIBO MODULE UNBERTHED FROM SHUTTLE PAYLOAD BAY PLAY
VIDEO: CLOSEUP INSPECTION OF STATION'S SOLAR ROTARY JOINT PLAY
VIDEO: FOSSUM UNBOLTS LOCKS ON KIBO'S WINDOW COVERINGS PLAY
VIDEO: SPACEWALKERS REMOVE COVERS ON KIBO'S PORT PLAY
VIDEO: SHUTTLE POWER UMBILICALS UNHOOKED FROM KIBO PLAY
VIDEO: SHUTTLE INSPECTION BOOM RETRIEVED FROM THE STATION PLAY
VIDEO: SPACEWALKER RON GARAN REMOVES COVER ON BOOM PLAY
VIDEO: SPACEWALKER MIKE FOSSUM FREES ARM'S ELBOW CAMERA PLAY
VIDEO: ANIMATION OF KIBO MODULE INSTALLATION PLAY
VIDEO: ANIMATION OF INSPECTION BOOM RETRIEVAL PLAY
VIDEO: NARRATED PREVIEW OF SPACEWALK NO. 1 PLAY
VIDEO: TUESDAY'S FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: THE FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: CREW'S REMARKABLE CAMCORDER FOOTAGE FROM MONDAY PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED INTO STATION PLAY
VIDEO: DISCOVERY DOCKS TO SPACE STATION PLAY
VIDEO: SHUTTLE PERFORMS RENDEZVOUS BACKFLIP PLAY

VIDEO: THE FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: CREW'S CAMCORDER FOOTAGE FROM FLIGHT DAY 2 PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY

VIDEO: THE FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: EXTERNAL TANK SEEN AFTER SEPARATION PLAY
VIDEO: LAUNCH REPLAY: VAB ROOF PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-1 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-2 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-6 PLAY
VIDEO: LAUNCH REPLAY: FRONT CAMERA PLAY
VIDEO: LAUNCH REPLAY: BEACH TRACKER PLAY
VIDEO: LAUNCH REPLAY: PAD PERIMETER PLAY
VIDEO: LAUNCH REPLAY: UCS-12 TRACKER PLAY
VIDEO: LAUNCH REPLAY: UCS-23 TRACKER PLAY
VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY
VIDEO: LAUNCH REPLAY: PATRICK AIR FORCE BASE PLAY
VIDEO: LAUNCH REPLAY: PRESS SITE PLAY
VIDEO: LAUNCH REPLAY: WEST TOWER PLAY
VIDEO: LAUNCH REPLAY: CAMERA 009 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 041 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 049 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 050 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 051 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 054 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 060 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 061 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 063 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 070 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 071 PLAY

VIDEO: LIFTOFF OF DISCOVERY WITH KIBO LAB! PLAY
VIDEO: ONBOARD CAMERA FOOTAGE OF TANK FOAM FALLING PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: POST-LAUNCH NEWS CONFERENCE PLAY

VIDEO: FINAL PRE-LAUNCH POLLS GIVE "GO" FOR LIFTOFF PLAY
VIDEO: ASTRONAUTS ARRIVE AT LAUNCH PAD 39A PLAY
VIDEO: CREW DEPARTS QUARTERS FOR LAUNCH PAD PLAY
VIDEO: ASTRONAUTS DON SPACESUITS FOR LAUNCH PLAY
VIDEO: NARRATED RECAP OF KIBO LAB'S PRE-FLIGHT CAMPAIGN PLAY
VIDEO: NARRATED RECAP OF DISCOVERY'S PRE-FLIGHT CAMPAIGN PLAY
VIDEO: LAUNCH PAD GANTRY RETRACTED FRIDAY NIGHT PLAY
VIDEO: TIME-LAPSE OF GANTRY ROLLBACK PLAY
VIDEO: FRIDAY'S COUNTDOWN STATUS BRIEFING PLAY
VIDEO: PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: BRIEFING ON KIBO LABORATORY FACILITY PLAY
VIDEO: ASTRONAUTS ARRIVE AT THE CAPE FOR LAUNCH PLAY
VIDEO: WEDNESDAY'S COUNTDOWN AND WEATHER BRIEFING PLAY
VIDEO: NARRATED MISSION PREVIEW MOVIE PLAY

VIDEO: NEWS BRIEFING FOLLOWING FLIGHT READINESS REVIEW PLAY

VIDEO: INTERVIEW WITH COMMANDER MARK KELLY PLAY
VIDEO: INTERVIEW WITH PILOT KEN HAM PLAY
VIDEO: INTERVIEW WITH MS1 KAREN NYBERG PLAY
VIDEO: INTERVIEW WITH MS2 RON GARAN PLAY
VIDEO: INTERVIEW WITH MS3 MIKE FOSSUM PLAY
VIDEO: INTERVIEW WITH MS4 AKIHIKO HOSHIDE PLAY

VIDEO: ASTRONAUTS PRACTICE EVACUATION OF SHUTTLE PLAY
VIDEO: CREW BOARDS DISCOVERY FOR PRACTICE COUNTDOWN PLAY
VIDEO: TRAINING SESSIONS AT LAUNCH PAD AND BUNKER PLAY
VIDEO: CREW NEWS CONFERENCE AT LAUNCH PAD 39A PLAY
VIDEO: ASTRONAUTS ARRIVE FOR PRACTICE COUNTDOWN PLAY

VIDEO: TIME-LAPSE OF GANTRY ENCLOSING DISCOVERY PLAY
VIDEO: PAD'S ORBITER ACCESS ARM SWUNG INTO POSITION PLAY
VIDEO: TIME-LAPSE OF CRAWLER RETREATING AFTER ROLLOUT PLAY
VIDEO: SHUTTLE DISCOVERY ROLLED TO PAD 39A PLAY

VIDEO: SHUTTLE AND STATION PROGRAM BRIEFING PLAY
VIDEO: STS-124 MISSION OVERVIEW PART 1 | PART 2
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: KIBO LABORATORY TRAVELS TO THE LAUNCH PAD PLAY
VIDEO: TRANSPORT CANISTER WITH KIBO ROTATED UPRIGHT PLAY
VIDEO: CRANE PLACES KIBO MODULE INTO TRANSPORT CANISTER PLAY

VIDEO: DISCOVERY HOISTED FOR ATTACHMENT TO FUEL TANK PLAY
VIDEO: THE SHUTTLE MOVES TO THE VEHICLE ASSEMBLY BUILDING PLAY
MORE: STS-124 VIDEO COVERAGE
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