The Endeavour astronauts tested the shuttle's re-entry systems today before packing up for the trip back to Earth Friday to close out a 16-day space station assembly mission. There are no technical problems of any significance, but forecasters are predicting a slight chance for rain and thunderstorms near Endeavour's Florida runway at the 10:48 a.m. EDT landing time.

Credit: NASA

Aboard the International Space Station, meanwhile, flight engineer Michael Barratt reviewed plans to troubleshoot another problem with the lab's U.S. carbon dioxide removal assembly, or CDRA, which is currently out of action after a restart failure.

The station's six-man crew relies on the CDRA and a Russian device known as the Vozdukh to scrub CO2 from the lab's air supply. Both systems are required to support six crew members, but lithium hydroxide canisters are available as a backup if either system fails.

An apparent heater controller problem caused a CDRA shutdown and circuit breaker trip last weekend. Engineers initially came up with a manual work-around and then a software patch to bypass the open circuit breaker, returning the CDRA to normal operation. Early today, the crew was informed of another problem.

"We had a CDRA failure again, so we'll be needing your assistance with the troubleshooting plan," Zach Jones called from Houston during the crew's morning planning conference. "As you know, during the docked mission the primary heaters on bed 2 failed and we implemented a work around to support the docked mission. Yesterday, during the powerup and restart we noticed that the procedure failed due to a firmware controller on bed 2. This is the same bed as the heater failure, so we suspect the controller is what is the problem here.

"Our troubleshooting plan will call for attempting to re-power the CDRA from an alternate power source. ... If that re-power attempt is unsuccessful, we'll have you back out of that jumper config and we'll subsequently perform a firmware controller R & R (replacement). We're still pulling together that plan and we anticipate starting that activity around 12:30 GMT. We'll have Mike as the prime crew member performing the task, probably with Bob (Thirsk) assisting throughout. We anticipate the task to take a total of six hours and we'll be clearing your schedule in the afternoon to accommodate the R & R task.

"If this plan is unsuccessful for whatever reason, we will have a plan in place to install LIOH canisters prior to crew sleep."

More than 1,000 miles ahead of the space station in a slightly lower orbit, Endeavour commander Mark Polansky, pilot Douglas Hurley and flight engineer Julie Payette worked through a standard day-before-entry timeline, testing the ship's hydraulic power system, steering jets and control systems.

Along with finishing work to stow loose gear, the astronauts also planned to break out their pressure suits and set up a recumbent seat for returning space station flight engineer Koichi Wakata to ease his return to gravity after four months in the weightlessness of space.

There were no problems of any significance during the flight control system checkout and while one forward thruster failed a "hot-fire" test, flight controllers said it would have no impact on entry.

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

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

02:03 AM...14...08...00...STS crew wakeup
04:28 AM...14...10...25...PILOT operations
05:13 AM...14...11...10...Cabin stow
05:28 AM...14...11...25...FCS checkout
07:03 AM...14...13...00...SEITE-2 thruster plume experiment
07:24 AM...14...13...21...Orbit adjust rocket firing
07:28 AM...14...13...25...RCS hotfire (actual: about 4:40 AM)
08:00 AM...14...13...57...Augustine committee hearing
08:33 AM...14...14...30...Dragon deploy
09:18 AM...14...15...15...Crew meal
10:18 AM...14...16...15...PAO event
10:38 AM...14...16...35...Deorbit review
01:00 PM...14...18...57...Mission status briefing
01:22 PM...14...19...19...ANDE deploy
01:28 PM...14...19...25...Ergometer stow
01:53 PM...14...19...50...Recumbent seat setup
01:58 PM...14...19...55...Wing leading edge sensor deact
02:18 PM...14...20...15...PGSC stow (part 1)
02:23 PM...14...20...20...LES checkout
02:53 PM...14...20...50...KU antenna stow
04:00 PM...14...21...57...Post-MMT briefing
06:03 PM...15...00...00...Crew sleep begins
07:00 PM...15...00...57...Daily highlights

As of Wednesday evening, the Spaceflight Meteorology Group at the Johnson Space Center in Houston was predicting scattered clouds at 8,000 feet, a broken deck at 25,000 feet, light winds out of the south-southeast and a slight chance of showers and thunderstorms within 30 nautical miles of the runway. The chance for rain increases for the second opportunity one orbit later.

Here is a list of all landing opportunities through Sunday (in EDT throughout; best viewed with fixed-width font):

ORBIT...SITE...DEORBIT.......LANDING

Friday, July 31

248.....KSC...09:42 AM.......10:48 AM
249.....KSC...11:16 AM.......12:22 PM

Saturday, Aug. 1

264.....KSC...10:05 AM.......11:08 AM
265.....NOR...11:37 AM.......12:39 PM
.........KSC...11:41 AM.......12:43 PM
266.....EDW...01:10 PM.......02:12 PM
.........NOR...01:12 PM.......02:14 PM
267.....EDW...02:46 PM.......03:48 PM

Sunday, Aug. 2

279.....KSC...08:50 AM.......09:53 AM
280.....KSC...10:25 AM.......11:27 AM
281.....EDW...11:55 AM.......12:58 PM
..........NOR...11:57 AM.......12:59 PM
282.....EDW...01:30 PM.......02:32 PM
..........NOR...01:33 PM.......02:34 PM
283.....EDW...03:07 PM.......04:08 PM

Additional coverage for subscribers:
VIDEO: FLIGHT DAY 15 HIGHLIGHTS MOVIE PLAY
VIDEO: DRAMATIC DOCKING OF CARGO SHIP TO SPACE STATION PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY

VIDEO: FLIGHT DAY 14 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE FLIES AWAY FROM STATION PLAY
VIDEO: STUNNING VIEWS OF STATION DURING FLYAROUND PLAY
VIDEO: FOOTAGE OF ENDEAVOUR DURING THE VICTORY LAP PLAY
VIDEO: THE TWO SPACECRAFT PASS INTO ORBITAL SUNRISE PLAY
VIDEO: ENDEAVOUR UNDOCKS FROM THE SPACE STATION PLAY
VIDEO: FAREWELL CEREMONY BETWEEN SHUTTLE AND ISS CREWS PLAY
VIDEO: CREW FLOATS INTO ENDEAVOUR AND CLOSES HATCHWAY PLAY
VIDEO: ASTRONAUTS LEAVE THEIR MARK INSIDE THE STATION PLAY
VIDEO: NARRATED ANIMATION OF UNDOCKING AND FLYAROUND PLAY
VIDEO: TUESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 13 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: FIFTH AND FINAL SPACEWALK COMPLETED PLAY
VIDEO: SECOND CAMERA PUT ON JAPAN'S EXPOSED FACILITY PLAY
VIDEO: FIRST TELEVISION CAMERA INSTALLED BY SPACEWALKERS PLAY
VIDEO: CASSIDY RE-WIRES STATION ELECTRICAL CABLES PLAY
VIDEO: MONDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 12 HIGHLIGHTS MOVIE PLAY
VIDEO: INTERNATIONAL NEWS CONFERENCE WITH ASTRONAUTS PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SUNDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 12 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 11 HIGHLIGHTS MOVIE PLAY
VIDEO: INTERNATIONAL MESSAGE FROM SHUTTLE AND ISS CREWS PLAY
VIDEO: INDY, CBS NEWS AND MEMPHIS MEDIA INTERVIEWS PLAY
VIDEO: SATURDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 10 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: DELIVERY PALLET RETURNS TO SHUTTLE PLAY
VIDEO: LAST OF THE OLD BATTERIES STOWED AWAY PLAY
VIDEO: SIXTH AND FINAL NEW BATTERY IS PLUGGED IN PLAY
VIDEO: SPACEWALKERS RESUME WORK WITH BATTERY CHARLIE PLAY
VIDEO: FRIDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 9 HIGHLIGHTS MOVIE PLAY
VIDEO: THURSDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: MORE INTERVIEWS WITH LAS VEGAS, HOUSTON AND FOX PLAY
VIDEO: NORTH CAROLINA, MAINE AND ORLANDO TV INTERVIEWS PLAY
VIDEO: COMMUNICATIONS PACKAGE PUT ON SCIENCE DECK PLAY
VIDEO: X-RAY ASTRONOMY PAYLOAD INSTALLED ON STATION PLAY
VIDEO: THURSDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 9 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 8 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: EARLY END TO SPACEWALK NO. 3 DECLARED PLAY
VIDEO: SECOND FRESH BATTERY PUT INTO STATION TRUSS PLAY
VIDEO: FIRST OF THE NEW BATTERIES INSTALLED PLAY
VIDEO: SPACEWALKERS REMOVE FIRST OLD BATTERY PLAY
VIDEO: CHRIS CASSIDY PREPS JAPANESE EXPERIMENTS PLAY
VIDEO: WEDNESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 3 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: FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: CREW ANSWERS PUBLIC'S QUESTIONS FROM SPACE PLAY
VIDEO: EXPOSED FACILITY RECEIVES EXPERIMENT CARRIER PLAY
VIDEO: JAPANESE EXPERIMENTS UNBERTHED FROM SHUTTLE PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 7 ACTIVITIES PLAY
VIDEO: TUESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: REPLACEMENT COOLING PUMP PUT ON STATION PLAY
VIDEO: SPARE COMMUNICATIONS ANTENNA TRANSFERRED PLAY
VIDEO: SPACEWALKER HOPS ABOARD STATION ARM PLAY
VIDEO: WOLF AND MARSHBURN BEGIN EVA NO. 2 PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 6 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 2 PLAY
VIDEO: MONDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 6 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 2 PLAY

VIDEO: FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: CANADIANS IN SPACE PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: PALLET HANDED OFF TO SPACE STATION PLAY
VIDEO: CARGO CARRIER UNBERTHED FROM SHUTTLE BAY PLAY
VIDEO: SUNDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 5 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: SATURDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: UPDATE ON ENDEAVOUR'S HEAT SHIELD CHECKS PLAY
VIDEO: JAPANESE OUTDOOR SCIENCE PLATFORM ATTACHED PLAY
VIDEO: SHUTTLE AND STATION ARMS HANDOFF SCIENCE DECK PLAY
VIDEO: JAPAN'S EXPOSED FACILITY UNBERTHED FROM SHUTTLE PLAY
VIDEO: THERMAL COVER JETTISONED FROM THE KIBO MODULE PLAY
VIDEO: HELMET-CAMERA VIEWS AS KOPRA CLIMBS TO SHUTTLE PLAY
VIDEO: TIM KOPRA EMERGES FROM AIRLOCK FOR EVA NO. 1 PLAY
VIDEO: SATURDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 4 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 1 PLAY
VIDEO: NARRATED TOUR OF ENDEAVOUR'S PAYLOAD BAY PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: ENDEAVOUR DOCKS TO THE SPACE STATION PLAY
VIDEO: ASTRONAUTS' ONBOARD CAMCORDER FOOTAGE PLAY
VIDEO: SHUTTLE FLIES OUT IN FRONT OF STATION PLAY
VIDEO: ENDEAVOUR PERFORMS 360-DEGREE BACKFLIP PLAY
VIDEO: BEAUTIFUL VIEWS OF ENDEAVOUR APPROACHING PLAY
VIDEO: STATION CAMERA CATCHES ENDEAVOUR'S "TI BURN" PLAY
VIDEO: NARRATED PREVIEW OF RENDEZVOUS AND DOCKING PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: PREVIEW ANIMATION OF HEAT SHIELD INSPECTIONS PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: THE FULL STS-127 LAUNCH EXPERIENCE PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH 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: UCS-23 TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PATRICK AIR FORCE BASE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BANANA CREEK VIP SITE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD FRONT CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: WEST TOWER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CAMERA 070 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CAMERA 071 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CAMERA CS-1 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-2 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-6 PLAY

VIDEO: SHUTTLE ENDEAVOUR BLASTS OFF! PLAY | HI-DEF
VIDEO: STS-127 POST-LAUNCH NEWS CONFERENCE PLAY
VIDEO: FOOTAGE OF FUEL TANK AFTER JETTISON PLAY
VIDEO: ASTRONAUTS REACH PAD 39A PLAY | HI-DEF
VIDEO: CREW DEPARTS QUARTERS FOR LAUNCH PAD PLAY | HI-DEF
VIDEO: ASTRONAUTS DON SPACESUITS FOR LAUNCH PLAY | HI-DEF

VIDEO: WEATHER SCRUBS LAUNCH AGAIN PLAY | HI-DEF
VIDEO: CREW ARRIVES AT PAD 39A ON MONDAY PLAY | HI-DEF
VIDEO: CREW DEPARTS QUARTERS ON MONDAY PLAY | HI-DEF
VIDEO: ASTRONAUTS SUIT UP ON MONDAY PLAY | HI-DEF

VIDEO: THUNDERSTORMS SCRUB SUNDAY'S ATTEMPT PLAY | HI-DEF
VIDEO: CREW DEPARTS QUARTERS ON SUNDAY PLAY | HI-DEF
VIDEO: ASTRONAUTS SUIT UP ON SUNDAY PLAY | HI-DEF
VIDEO: NARRATED SUMMARY SHUTTLE'S PREPARATIONS PLAY | HI-DEF
VIDEO: NARRATED SUMMARY PAYLOADS' PREPARATIONS PLAY | HI-DEF

VIDEO: LIGHTNING STRIKES POSTPONE ENDEAVOUR LAUNCH PLAY
VIDEO: FRIDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: THURSDAY'S STATUS REPORT ON THE COUNTDOWN PLAY
VIDEO: COUNTDOWN PREVIEW AND WEATHER BRIEFING PLAY
VIDEO: ASTRONAUTS RETURN TO CAPE FOR LAUNCH PLAY | HI-DEF

VIDEO: NO LEAKS FOUND DURING SPECIAL TEST PLAY
VIDEO: EXPLANATION OF THE HYDROGEN LEAK AND THE REPAIR PLAY

VIDEO: POST-SCRUB NEWS BRIEFING PLAY
VIDEO: FIRING ROOM UPDATE WITH LAUNCH DIRECTOR PLAY
VIDEO: SCRUB NO. 2 DECLARED DUE TO HYDROGEN LEAK PLAY

VIDEO: SUNDAY'S UPDATE FROM MISSION MANAGEMENT TEAM PLAY
VIDEO: LEAK POSTPONES SHUTTLE ENDEAVOUR LAUNCH PLAY

VIDEO: TIME-LAPSE OF SUN SETTING OVER PAD 39A PLAY
VIDEO: ANOTHER TIME-LAPSE OF GANTRY RETRACTION PLAY
VIDEO: TIME-LAPSE OF LAUNCH PAD TOWER ROLLBACK PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH MARK POLANSKY PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH DOUG HURLEY PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH CHRIS CASSIDY PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH JULIE PAYETTE PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH TOM MARSHBURN PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH DAVE WOLF PLAY

VIDEO: THE STS-127 MISSION PREVIEW MOVIE PLAY
VIDEO: THURSDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: JAPANESE SCIENCE FACILITIES ABOARD STATION PLAY
VIDEO: COUNTDOWN BEGINS TICKING FOR SATURDAY'S LAUNCH PLAY
VIDEO: LAUNCH COUNTDOWN PREVIEW BRIEFING PLAY
VIDEO: CREW ARRIVES JUST BEFORE MIDNIGHT PLAY | HI-DEF
VIDEO: GET TO KNOW ENDEAVOUR'S ASTRONAUTS PLAY

VIDEO: ASTRONAUTS PRACTICE EVACUATION OF SHUTTLE PLAY | HI-DEF
VIDEO: CREW BOARDS SHUTTLE FOR PRACTICE COUNT PLAY | HI-DEF
VIDEO: ASTRONAUTS SUIT UP FOR DRESS REHEARSAL PLAY | HI-DEF
VIDEO: CREW INSPECTS CARGO IN THE PAYLOAD BAY PLAY | HI-DEF
VIDEO: TRAINING SESSIONS AT LAUNCH PAD AND BUNKER PLAY | HI-DEF
VIDEO: INFORMAL CREW NEWS CONFERENCE AT LAUNCH PAD PLAY
VIDEO: ASTRONAUTS ARRIVE FOR PRACTICE COUNTDOWN PLAY

VIDEO: FLIGHT READINESS REVIEW SETS LAUNCH DATE PLAY

VIDEO: PAD 39A GANTRY ENCLOSES SHUTTLE PLAY | HI-DEF
VIDEO: ROLLAROUND MOVES ENDEAVOUR TO PAD 39A PLAY | HI-DEF
VIDEO: ENDEAVOUR IS HAULED OFF LAUNCH PAD 39B PLAY | HI-DEF
VIDEO: TIME-LAPSE OF SHUTTLE'S LAUNCH PAD SWITCH PLAY

VIDEO: SHUTTLE AND STATION PROGRAM UPDATE PLAY
VIDEO: THE STS-127 MISSION OVERVIEW BRIEFING PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: PAD 39B AND ITS LAST SPACE SHUTTLE PLAY | HI-DEF
VIDEO: ENDEAVOUR'S SUNRISE ARRIVAL AT PAD 39B PLAY | HI-DEF
VIDEO: MIDNIGHT ROLLOUT FROM ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: ENDEAVOUR HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: CRANE ROTATES ENDEAVOUR VERTICALLY PLAY | HI-DEF
VIDEO: ENDEAVOUR MOVES TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: ORION AND ARES ROCKET PROGRESS REPORT PLAY
SUBSCRIBE NOW