The Endeavour astronauts are prepping the shuttle for undocking and separation from the International Space Station this evening, leaving the lab complex more than 98 percent complete after the delivery of a new habitation module and multi-window cupola.

Credit: NASA

Aboard the space station, meanwhile, commander Jeffrey Williams and T.J. Creamer plan to carry out a detailed internal inspection of the lab's U.S. water recycling racks to look for any signs of a leak or other problem that might explain the apparent loss of about two pints of urine.

The loss was noted after the water processing racks were moved into the new Tranquility module and reactivated. Engineers do not believe any urine actually leaked out of the processor's plumbing, but it's not yet clear what went wrong during two attempts to re-activate the urine processing system. The inspections will not conflict with Endeavour's scheduled undocking.

With pilot Terry Virts at the controls, undocking is planned for 7:54 p.m. EST. Virts plans to pull out directly in front of the station before beginning a 360-degree photo-documentation fly around.

"Undocking day's always a big day for the pilot because we get to fly the undocking and so that's going to be a lot of fun," Virts said in a NASA interview. "We're going to slowly back away from the station. At about 400 feet, we'll start to fly up above the station. We're going to fly a 600-foot circle around it and we should get some great views.

"What we'll be seeing will be the first time that the station is in basically its final configuration. We'll see node 3 (Tranquility), the cupola, all the major station modules will be there at that point and so that's going to be a lot of fun."

At the end of the fly around, Virts and commander George Zamka will oversee a rocket firing around 9:37 p.m. to leave the area. The shuttle astronauts plan to spend the rest of their "day" inspecting the ship's reinforced carbon carbon nose cap and wing leading edge panels to look for any signs of micrometeoroid impact damage that might have occurred since a similar inspection the day after launch.

"The whole crew will be involved in doing a late inspection where we take the boom sensor system and we move it around the shuttle to look to make sure there hasn't been any damage to the shuttle while we were in space, during our, roughly, two weeks in space," Virts said.

A mission status briefing is planned for 1:30 a.m. Saturday and the crew will call it a day at 7:14 a.m. The astronauts plan to pack up and test Endeavour's entry systems overnight Saturday.

Landing back at the Kennedy Space Center is targeted for 10:16 p.m. Sunday, weather permitting. The forecast for Sunday and Monday night at both Kennedy and Edwards Air Force Base, Calif., calls for showers, or a chance for showers, within 30 nautical miles.

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

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

02/19
03:14 PM...11...11...00...Crew wakeup
05:09 PM...11...12...55...ISS daily planning conference
05:45 PM...11...13...30...53...US Arrays Feathered
05:59 PM...11...13...45...Group B computer powerup
06:07 PM...11...13...53...14...Sunset
06:39 PM...11...14...24...54...Maneuver to Undock Attitude
06:42 PM...11...14...28...37...Sunrise
07:07 PM...11...14...52...53...Orbiter/ISS in Undock Attitude
07:09 PM...11...14...55...Undocking timeline begins
07:10 PM...11...14...56...38...Noon
07:38 PM...11...15...24...39...Sunset
07:44 PM...11...15...30...Russian Segment Arrays Feathered

07:54 PM...11...15...40...Undocking

07:55 PM...11...15...41...Initial Separation Pulses
07:55 PM...11...15...41...40...ISS Holds Current Attitude
07:59 PM...11...15...45...Range = 50 feet
08:01 PM...11...15...47...Range = 75 feet
08:14 PM...11...16...11...Sunrise
08:14 PM...11...16...12...RS Arrays Resume Tracking
08:23 PM...11...16...09...Range = 400 ft; Start Flyaround
08:32 PM...11...16...18...30...Range = 600 feet
08:32 PM...11...16...18...31...US Arrays Resume Tracking
08:33 PM...11...16...18...54...ISS Maneuver to normal attitude begins
08:34 PM...11...16...20...30...Shuttle directly above ISS
08:42 PM...11...16...28...08...Noon
08:46 PM...11...16...32...Shuttle directly behind ISS
08:57 PM...11...16...43...30...Shuttle directly below ISS
09:09 PM...11...16...55...Sep 1 Burn
09:10 PM...11...16...56...05...Sunset
09:37 PM...11...17...23...Sep 2 Burn
09:39 PM...11...17...25...Post-undocking PGSC reconfig
09:54 PM...11...17...40...Group B computer powerdown
10:09 PM...11...17...55...Crew meals begin
10:34 PM...11...18...20...Playback ops

02/20
12:19 AM...11...20...05...Starboard wing survey
01:30 AM...11...21...16...Mission status briefing on NTV
01:59 AM...11...21...45...EVA unpack and stow
02:04 AM...11...21...50...Nose cap survey
02:54 AM...11...22...40...Post EVA entry preps
02:54 AM...11...22...40...Port wing survey
04:39 AM...12...25...00...LDRI downlink
07:14 AM...12...03...00...STS crew sleep begins
08:00 AM...12...03...46...Daily highlights on NTV
03:14 PM...12...11...00...Crew wakeup

Additional coverage for subscribers:
VIDEO: PREVIEW OF FLIGHT DAY 13 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 12 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE AND STATION CREWS BID THEIR FAREWELLS PLAY
VIDEO: RIBBON-CUTTING CEREMONY FOR STATION'S CUPOLA PLAY
VIDEO: IN-FLIGHT CREW NEWS CONFERENCE FOR U.S AND JAPAN PLAY

VIDEO: FLIGHT DAY 11 HIGHLIGHTS MOVIE PLAY
VIDEO: THURSDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: OXYGEN GENERATOR RELOCATED TO TRANQUILITY PLAY
VIDEO: STATION'S TOILET INSTALLED IN THE NEW MODULE PLAY
VIDEO: WATER GENERATING EQUIPMENT MOVED INTO TRANQUILITY PLAY
VIDEO: PRESIDENT OBAMA CALLS SHUTTLE AND STATION CREWS PLAY

VIDEO: DAZZLING VIEWS FROM INSIDE CUPOLA PLAY
VIDEO: CUPOLA WINDOW SHUTTERS ARE TESTED PLAY
VIDEO: STATION ASTRONAUT'S CAMCORDER VIEWS OF CUPOLA PLAY
VIDEO: FLIGHT DAY 10 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: CUPOLA OPEN FOR VIEWING PLAY
VIDEO: FREEING THE SHUTTERS PLAY
VIDEO: CUPOLA IS UNVEILED! PLAY
VIDEO: FIRST HALF OF CUPOLA UNCOVERED PLAY
VIDEO: WIRING UP DOCKING ADAPTER ON TRANQUILITY PLAY
VIDEO: ACTIVATING TRANQUILITY'S OTHER COOLING LOOP PLAY
VIDEO: SPACEWALKERS FLOAT OUT OF AIRLOCK PLAY
VIDEO: STEP-BY-STEP PREVIEW OF SPACEWALK NO. 3 PLAY
VIDEO: PREVIEW OF FLIGHT DAY 10 ACTIVITIES PLAY

VIDEO: FLY WITH THE ASTRONAUTS IN THE COCKPIT PLAY
VIDEO: LOOKING OUT THE PILOT'S FRONT WINDOW 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 INBOARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING DOWNWARD PLAY
VIDEO: EXTERNAL TANK CAMERA FROM LIFTOFF TO SEPARATION PLAY

VIDEO: FLIGHT DAY 9 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: DOCKING ADAPTER PLACED ONTO TRANQUILITY PLAY
VIDEO: PREVIEW OF FLIGHT DAY 9 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 8 HIGHLIGHTS MOVIE PLAY
VIDEO: NEW YORK, ST. LOUIS AND MEMPHIS MEDIA INTERVIEWS PLAY
VIDEO: MONDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: OBSERVATION PORTAL RELOCATED TO NEW HOME PLAY
VIDEO: CUPOLA PLUCKED FROM OUTBOARD PORT PLAY
VIDEO: ROBOTIC ARM GRAPPLES CUPOLA PLAY
VIDEO: CREW'S EDUCATIONAL EVENT PLAY
VIDEO: PREVIEW OF FLIGHT DAY 8 ACTIVITIES PLAY
VIDEO: SUNDAY AFTERNOON'S FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: SUNDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: PREPPING CUPOLA'S NEW HOME PORT PLAY
VIDEO: SPACEWALKERS COMPLETE OTHER OUTFITTING WORK PLAY
VIDEO: AMMONIA BEGINS FLOWING TO COOL TRANQUILITY PLAY
VIDEO: PATRICK'S SPACESUIT CONTAMINATION CHECKS PLAY
VIDEO: SPACEWALKERS INSTALL SECOND COOLANT LOOP PLAY
VIDEO: FIRST SET OF AMMONIA LINES HOOKED UP PLAY
VIDEO: PREVIEW OF FLIGHT DAY 7 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP PREVIEW OF SPACEWALK NO. 2 PLAY

VIDEO: FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: OPENING CUPOLA'S HATCHWAY BRIEFLY PLAY
VIDEO: ENTERING TRANQUILITY FOR FIRST TIME PLAY
VIDEO: SPACEWALKERS ANSWER TWITTER QUESTIONS PLAY
VIDEO: ASSOCIATED PRESS, CBS AND REUTERS MEDIA INTERVIEWS PLAY
VIDEO: SATURDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: PREVIEW OF FLIGHT DAY 6 ACTIVITIES PLAY

VIDEO: FRIDAY AFTERNOON'S MANAGEMENT TEAM UPDATE PLAY
VIDEO: FRIDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: STEP-BY-STEP PREVIEW OF SPACEWALK NO. 1 PLAY
VIDEO: PREVIEW OF FLIGHT DAY 5 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY NIGHT'S MISSION STATUS BRIEFING PLAY
VIDEO: SACRAMENTO, MOBILE AND ST. LOUIS MEDIA INTERVIEWS PLAY
VIDEO: WEDNESDAY AFTERNOON'S MANAGEMENT TEAM UPDATE PLAY
VIDEO: WEDNESDAY MORNING'S FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: PREVIEW OF FLIGHT DAY 4 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY MORNING'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: HATCHWAY OPENED BETWEEN TWO SPACECRAFT PLAY
VIDEO: ENDEAVOUR DOCKS TO THE SPACE STATION PLAY
VIDEO: SHUTTLE FLIES OUT IN FRONT OF STATION PLAY
VIDEO: ENDEAVOUR PERFORMS 360-DEGREE BACKFLIP PLAY
VIDEO: STUNNING SHOT OF SHUTTLE AGAINST HORIZON PLAY
VIDEO: STATION'S VIEW OF SHUTTLE ENGINE FIRING PLAY
VIDEO: PREVIEW OF FLIGHT DAY 3 ACTIVITIES PLAY
VIDEO: TUESDAY AFTERNOON'S MANAGEMENT TEAM UPDATE PLAY

VIDEO: AMAZING LAUNCH FOOTAGE FROM COCKPIT CAMERA PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: TIME-LAPSE OF WING INSPECTIONS PLAY
VIDEO: INSPECTION BOOM READIED FOR USE PLAY
VIDEO: PREVIEW OF FLIGHT DAY 2 ACTIVITIES PLAY
VIDEO: NARRATED TOUR OF ENDEAVOUR'S PAYLOAD BAY PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: THE FULL STS-130 LAUNCH EXPERIENCE PLAY
VIDEO: SHUTTLE ENDEAVOUR BLASTS OFF! PLAY | HI-DEF
VIDEO: GO BEHIND THE SCENES IN MISSION CONTROL PLAY
VIDEO: JETTISONED EXTERNAL FUEL TANK TUMBLES AWAY PLAY
VIDEO: PAYLOAD BAY DOORS OPENED FOLLOWING LAUNCH PLAY

VIDEO: CREW FINISHES GETTING SUITED UP PLAY
VIDEO: ASTRONAUTS LEAVE CREW QUARTERS PLAY | HI-DEF
VIDEO: CREW ARRIVES AT LAUNCH PAD 39A PLAY
VIDEO: ASTRONAUTS BOARD THEIR SPACECRAFT PLAY

VIDEO: LAUNCH REPLAY: VAB ROOF PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PRESS SITE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD PERIMETER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BEACH TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD CAMERA 070 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD CAMERA 071 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: UCS-23 TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD FRONT CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BANANA CREEK SITE PLAY | HI-DEF

VIDEO: NARRATED REVIEW OF SHUTTLE'S PREPARATIONS PLAY | HI-DEF
VIDEO: NARRATED REVIEW OF PAYLOADS' PREPARATIONS PLAY | HI-DEF

VIDEO: EXPLANATION OF WEATHER PROBLEMS PLAY | HI-DEF
VIDEO: LOW CLOUDS SCRUB FIRST COUNTDOWN PLAY | HI-DEF
VIDEO: ASTRONAUTS DEPART QUARTERS FOR PAD 39A PLAY | HI-DEF
VIDEO: CREW GETS SUITED UP FOR LAUNCH ATTEMPT PLAY | HI-DEF
VIDEO: PAD SERVICE GANTRY RETRACTED PLAY | HI-DEF
VIDEO: TIME-LAPSE OF MOBILE TOWER ROLLBACK PLAY

VIDEO: INTERVIEW WITH COMMANDER GEORGE ZAMKA PLAY
VIDEO: INTERVIEW WITH PILOT TERRY VIRTS PLAY
VIDEO: INTERVIEW WITH MISSION SPECIALIST 1 KAY HIRE PLAY
VIDEO: INTERVIEW WITH MISSION SPECIALIST 2 STEVE ROBINSON PLAY
VIDEO: INTERVIEW WITH MISSION SPECIALIST 3 NICK PATRICK PLAY
VIDEO: INTERVIEW WITH MISSION SPECIALIST 4 BOB BEHNKEN PLAY

VIDEO: ENDEAVOUR'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: THURSDAY STATUS AND WEATHER UPDATE PLAY
VIDEO: COUNTDOWN PREVIEW BRIEFING PLAY
VIDEO: ASTRONAUTS ARRIVE FOR LAUNCH PLAY | HI-DEF

VIDEO: LAUNCH DATE SET AT FLIGHT READINESS REVIEW PLAY
VIDEO: PAYLOAD BAY DOORS CLOSED FOR LAUNCH PLAY | HI-DEF
VIDEO: CREW SEES TRANQUILITY LOADED INTO SHUTTLE PLAY | HI-DEF

VIDEO: SHUTTLE EVACUATION PRACTICE PLAY | HI-DEF
VIDEO: ASTRONAUTS BOARD ENDEAVOUR PLAY | HI-DEF
VIDEO: THE LAUNCH DAY SIMULATION BEGINS PLAY | HI-DEF
VIDEO: PAD BUNKER TRAINING FOR THE CREW PLAY | HI-DEF
VIDEO: CREW BRIEFED ON EMERGENCY PROCEDURES PLAY | HI-DEF
VIDEO: TEST-DRIVING AN EMERGENCY ARMORED TANK PLAY | HI-DEF
VIDEO: NIGHTTIME APPROACHES IN TRAINING AIRCRAFT PLAY | HI-DEF
VIDEO: ASTRONAUTS CHAT WITH REPORTERS AT PAD 39A PLAY
VIDEO: SPACEWALKER UPDATES COOLING HOSE FIX PLAY | HI-DEF
VIDEO: ROBINSON'S THOUGHTS ON SHUTTLE RETIREMENT PLAY | HI-DEF
VIDEO: ASTRONAUTS ARRIVE FOR PRACTICE COUNTDOWN PLAY | HI-DEF

VIDEO: TRANQUILITY DELIVERED TO PAD 39A PLAY | HI-DEF
VIDEO: PAYLOAD TRANSPORTER GOES UPRIGHT PLAY | HI-DEF
VIDEO: PACKING UP PAYLOAD FOR LAUNCH PLAY | HI-DEF

VIDEO: SHUTTLE ENDEAVOUR'S FRIGID ROLLOUT TO PAD PLAY | HI-DEF
VIDEO: ENDEAVOUR HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: CRANE ROTATES THE ORBITER VERTICALLY PLAY | HI-DEF
VIDEO: ENDEAVOUR MOVES TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: TIME-LAPSE SHOWS ENDEAVOUR ASCENDING IN VAB PLAY
VIDEO: TIME-LAPSE SHOWS THE MOVE TO ASSEMBLY BUILDING PLAY

VIDEO: ORBITER READY TO LEAVE HANGAR PLAY | HI-DEF
VIDEO: EXTERNAL TANK ATTACHED TO BOOSTERS PLAY | HI-DEF
VIDEO: ENDEAVOUR'S MAIN ENGINE INSTALLATION PLAY | HI-DEF
VIDEO: ASTRONAUTS VISIT THEIR SPACECRAFT PLAY | HI-DEF
VIDEO: CREW INSPECTS MISSION PAYLOADS PLAY | HI-DEF
VIDEO: FUEL TANK UNLOADED FROM THE BARGE PLAY | HI-DEF
VIDEO: EXTERNAL TANK ARRIVES AT SPACEPORT PLAY | HI-DEF
VIDEO: FORWARD THRUSTER POD CHECKED OUT PLAY | HI-DEF
VIDEO: ENDEAVOUR TOWED OFF RUNWAY FROM STS-127 PLAY | HI-DEF

VIDEO: TRANQUILITY HATCH SEALED FOR LAUNCH PLAY | HI-DEF
VIDEO: CUPOLA ATTACHED TO TRANQUILITY PLAY | HI-DEF
VIDEO: THE SPACE STATION'S NEW CUPOLA PLAY | HI-DEF
VIDEO: TRANQUILITY UNPACKED IN FLORIDA PLAY | HI-DEF
VIDEO: NEW MODULE ARRIVES FROM EUROPE PLAY | HI-DEF
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