The Discovery astronauts are gearing up to undock from the International Space Station today to close out a successful resupply mission. After a 360-degree photo-documentation fly around, the astronauts will carry out a final inspection of the shuttle's critical nose cap and wing leading edge panels to set the stage for re-entry and landing Thursday.

Credit: NASA

Undocking is scheduled for 3:26 p.m. EDT. With shuttle pilot Kevin Ford at the controls, the shuttle will pull away directly in front of the space station before kicking off the fly-around maneuver, looping up above the lab complex at a distance of roughly 600 feet.

Shuttle pilots normally use smaller vernier jets, two in the nose and four in the tail, when maneuvering near the station. But one of Discovery's forward verniers suffered a leak shortly after launch, prompting flight controllers to close a shared propellant manifold that took out both forward jets. That action disabled the vernier system for the duration of the fight.

NASA engineers approved an alternate digital autopilot, or ALT-DAP, technique for using the the shuttle's more powerful primary reaction control system jets to reorient the shuttle-station complex for undocking, and for carrying out the planned fly around. Procedures were put in place to make sure no thruster plumes hit the station's delicate solar arrays.

Commander Frederick Sturckow successfully used the big jets for docking and flight controllers did not anticipate any problems for today's fly around.

"It should be a real thrill," Ford told CBS News before launch. "It's the reverse of the docking process. Some hooks will open and some springs will give us a little push off. And then my job is to make sure we stay pretty tight on the tolerances as we back away.

"The exciting part starts when we get to a certain range, maybe about 400 feet, I'll do some ups and we'll start a maneuver that takes the orbiter up and over the top of the space station and we'll do this full 360-degree fly around at about 650 feet.

"It's a great range, it's far enough away that the jets don't really impinge on station and it's also a good range for photography and a chance for us to take a lot of photos of the exterior of the station for documentation. And of course, sometimes the station gets some pictures of the orbiter flying around it. It'll be really spectacular."

Ford will be assisted by commander Rick Sturckow, flight engineer Jose Hernandez, John "Danny" Olivas, Patrick Forrester, European Space Agency astronaut Christer Fuglesang and returning space station flight engineer Timothy Kopra.

Kopra was replaced aboard the station by astronaut Nicole Stott, who was ferried to the lab complex aboard Discovery. She plans to remain aboard the station until November when another shuttle crew delivers more supplies and equipment.

After today's fly-around is complete, Discovery will leave the area. The shuttle crew then will turn its attention to a final heat shield inspection, using a laser scanner on the end of a 50-foot-long boom to look for any signs of damage to the shuttle's reinforced carbon carbon nose cap and wing leading edge panels.

The so-called "late inspection" is identical to a procedure carried out the day after launch to look for signs of ascent impact damage. This time around, engineers will be looking for any signs of damage from orbital debris or micrometeoroid impacts that might have occurred since the initial inspection.

The late inspection should be complete by around 11 p.m. The astronauts plan to spend the day Wednesday packing up and testing the shuttle's re-entry systems. Landing is targeted for 7:05 p.m. Thursday, weather permitting.

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

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

09/08
10:59 AM...10...11...00...00...STS/ISS crew wakeup
12:19 PM...10...12...20...00...ISS daily planning conference
01:04 PM...10...13...05...00...Group B computer powerup
01:29 PM...10...13...30...00...Maneuver to undocking attitude
02:44 PM...10...14...45...00...Undocking timeline begins
03:13 PM...10...15...14...12...Sunset
03:26 PM...10...15...27...00...UNDOCKING
03:27 PM...10...15...28...00...Initial separation
03:28 PM...10...15...28...40...ISS holds attitude
03:31 PM...10...15...32...00...Range: 50 feet; reselect -X jets
03:33 PM...10...15...34...00...Range 75 feet; low Z
03:34 PM...10...15...35...00...ISS: Undocking video
03:43 PM...10...15...43...47...Sunrise
03:55 PM...10...15...56...00...Range: 400 feet; start fly around
04:05 PM...10...16...05...30...Range: 600 feet
04:07 PM...10...16...07...30...Shuttle directly above ISS
04:14 PM...10...16...14...46...Noon
04:18 PM...10...16...19...00...Shuttle directly behind ISS
04:30 PM...10...16...30...30...Shuttle directly below ISS
04:41 PM...10...16...42...00...Separation burn No. 1
04:45 PM...10...16...45...44...Sunset
05:09 PM...10...17...10...06...Separation burn No. 2
05:14 PM...10...17...15...00...Post-undocking PGSC reconfig
05:14 PM...10...17...15...00...Group B computer powerdown
05:15 PM...10...17...15...26...Sunrise
05:29 PM...10...17...30...00...Crew meals begin
05:30 PM...10...17...31...00...Post-MMT briefing
05:59 PM...10...18...00...00...OBSS starboard wing survey
07:39 PM...10...19...40...00...Nose cap survey
07:49 PM...10...19...50...00...EVA unpack and stow
08:19 PM...10...20...20...00...PST ISS EVA entry preps
08:29 PM...10...20...30...00...Port wing survey
09:00 PM...10...21...01...00...Mission status briefing
11:14 PM...10...23...15...00...OBSS berthing

09/09
12:14 AM...11...00...15...00...SRMS powerdown
01:09 AM...11...01...10...00...Undocking video playback
02:59 AM...11...03...00...00...STS crew sleep begins
03:00 AM...11...03...01...00...Daily highlights
10:59 AM...11...11...00...00...Crew wakeup

Additional coverage for subscribers:
VIDEO: TUESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 11 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY EVENING'S MISSION STATUS BRIEFING PLAY
VIDEO: FAREWELL BETWEEN SHUTTLE AND STATION CREWS PLAY
VIDEO: LEONARDO MODULE RETURNED TO THE PAYLOAD BAY PLAY
VIDEO: ASTRONAUTS ANSWER QUESTIONS SUBMITTED BY PUBLIC PLAY
VIDEO: TELEMUNDO, TAMPA AND UNIVISION CREW INTERVIEWS PLAY
VIDEO: EL PASO AND AUSTIN TELEVISION CREW INTERVIEWS PLAY
VIDEO: JOSE HERNANDEZ LIVE INTERVIEWS FROM ORBIT PLAY
VIDEO: MONDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 10 HIGHLIGHTS MOVIE PLAY
VIDEO: EUROPEAN SPACE AGENCY ASTRONAUT EVENT PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 10 PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 9 PLAY
VIDEO: SUNDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: POST-EVA MISSION STATUS BRIEFING PLAY
VIDEO: FLIGHT DAY 9 HIGHLIGHTS MOVIE PLAY
VIDEO: FUGLESANG'S HELMET-CAM COMES LOOSE PLAY
VIDEO: ROUTING AVONICS CABLES FOR TRANQUILITY PLAY
VIDEO: FAILED ORIENTATION SENSOR REMOVED PLAY
VIDEO: WORK TO DEPLOY PAYLOAD MECHANISM PLAY
VIDEO: EVA NO. 3 BEGINS PLAY
VIDEO: SATURDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: ASTRONAUTS' HOME MOVIES: DAY 8 PLAY
VIDEO: INTERNATIONAL CREW NEWS CONFERENCE PLAY
VIDEO: FLIGHT DAY 8 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY AFTERNOON'S MISSION STATUS BRIEFING PLAY
VIDEO: FRIDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

HIGH DEFINITION TV DAY 7: SPACEWALKERS COME BACK INSIDE PLAY
HIGH DEFINITION TV DAY 7: MORE WORK WITH LEONARDO PLAY
HIGH DEFINITION TV DAY 7: OLIVAS AND FUGLESANG ON EVA PLAY

VIDEO: FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 7 PLAY
VIDEO: POST-EVA MISSION STATUS BRIEFING PLAY
VIDEO: OLD TANK MOVED TO SHUTTLE FOR RECYCLING PLAY
VIDEO: NEW TANK HOOKED UP TO STATION UMBILICALS PLAY
VIDEO: CHRISTER FUGLESANG CARRIES NEW AMMONIA TANK PLAY
VIDEO: PREPS IN SHUTTLE BAY TO UNPACK NEW AMMONIA TANK PLAY
VIDEO: DANNY OLIVAS FLOATS OUT OF AIRLOCK TO START EVA PLAY
VIDEO: THURSDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 2 PLAY

HIGH DEFINITION TV DAY 6: PREPPING FOR NEXT EVA PLAY
HIGH DEFINITION TV DAY 6: MOVING FROZEN SCIENCE PLAY
HIGH DEFINITION TV DAY 6: EMPTYING OUT LEONARDO PLAY

HIGH DEFINITION TV DAY 5: SPACEWALKERS CELEBRATE PLAY
HIGH DEFINITION TV DAY 5: OLIVAS AND STOTT ON EVA NO. 1 PLAY
HIGH DEFINITION TV DAY 5: COLBERT TREADMILL UNPACKED PLAY
HIGH DEFINITION TV DAY 5: SPACEWALKERS GET SUITED UP PLAY

HIGH DEFINITION TV DAY 4: LEONARDO MODULE OPENED PLAY
HIGH DEFINITION TV DAY 4: MOVING ITEMS FROM SHUTTLE PLAY

VIDEO: FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 6 PLAY
VIDEO: WEDNESDAY NIGHT'S MISSION STATUS BRIEFING PLAY
VIDEO: WEDNESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: POST-EVA MISSION STATUS BRIEFING PLAY
VIDEO: SPACEWALKERS PUT THIRD EXPERIMENT IN SHUTTLE PLAY
VIDEO: BRIEFCASE-LIKE PACKAGE RETRIEVED FROM STATION PLAY
VIDEO: EUROPEAN PAYLOAD MOVED FROM STATION TO SHUTTLE PLAY
VIDEO: SPACEWALKERS FREE COOLANT TANK FROM TRUSS PLAY
VIDEO: DANNY OLIVAS DISCONNECTS OLD AMMONIA TANK PLAY
VIDEO: ASTRONAUTS EMERGE FROM AIRLOCK TO START EVA PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 5 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 1 PLAY
VIDEO: TUESDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY NIGHT'S MISSION STATUS BRIEFING PLAY
VIDEO: NARRATED OVERVIEW OF THE LEONARDO PAYLOAD PLAY
VIDEO: ASTRONAUTS OPEN UP AND ENTER LEONARDO MODULE PLAY
VIDEO: TIME-LAPSE OF LEONARDO MODULE'S INSTALLATION PLAY
VIDEO: LEONARDO CARGO MODULE ATTACHED TO STATION PLAY
VIDEO: MONDAY'S MISSION MANAGEMENT TEAM UPDATE PLAY
VIDEO: MONDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY

HIGH DEFINITION TV DAY 3: NICOLE STOTT ABOARD STATION PLAY
HIGH DEFINITION TV DAY 3: UNITING STATION AND SHUTTLE PLAY
HIGH DEFINITION TV DAY 3: JOIN THE CREW DURING DOCKING PLAY
HIGH DEFINITION TV DAY 3: LIFE ON RENDEZVOUS DAY PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: SUNDAY NIGHT'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: DOCKING RING RETRACTED TO JOIN TWO CRAFT PLAY
VIDEO: TIME-LAPSE OF DOCKING FROM CENTERLINE PLAY
VIDEO: SHUTTLE FLIES OUT IN FRONT OF STATION PLAY
VIDEO: DISCOVERY PERFORMS 360-DEGREE BACKFLIP PLAY
VIDEO: BEAUTIFUL VIEWS OF DISCOVERY APPROACHING PLAY
VIDEO: TIME-LAPSE VIEW FROM SHUTTLE DOCKING PORT PLAY
VIDEO: STATION CAMERA CATCHES DISCOVERY'S "TI BURN" PLAY
VIDEO: SUNDAY'S MISSION MANAGEMENT TEAM UPDATE PLAY
VIDEO: NARRATED PREVIEW OF RENDEZVOUS AND DOCKING PLAY
VIDEO: THE MOON SINKS BELOW TAIL OF DISCOVERY PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 2 PLAY
VIDEO: ASTRONAUTS' HOME MOVIES: DAY 1 PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: SATURDAY NIGHT'S MISSION STATUS BRIEFING PLAY
VIDEO: NARRATED PREVIEW OF SHUTTLE INSPECTIONS PLAY

VIDEO: LAUNCH REPLAY: INSIDE MISSION CONTROL ROOM 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 CAEMRA 070 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD CAEMRA 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: PATRICK AIR FORCE BASE PLAY | HI-DEF

VIDEO: POST-LAUNCH BRIEFING PLAY
VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: THE FULL LAUNCH EXPERIENCE PLAY
VIDEO: LIFTOFF OF SPACE SHUTTLE DISCOVERY! PLAY | HI-DEF
VIDEO: COMMANDER RICK STURCKOW BOARDS DISCOVERY PLAY
VIDEO: PILOT KEVIN FORD BOARDS SHUTTLE DISCOVERY PLAY
VIDEO: MISSION SPECIALIST PAT FORRESTER BOARDS DISCOVERY PLAY
VIDEO: MISSION SPECIALIST JOSE HERNANDEZ BOARDS SHUTTLE PLAY
VIDEO: MISSION SPECIALIST DANNY OLIVAS BOARDS DISCOVERY PLAY
VIDEO: MISSION SPECIALIST CHRISTER FUGLESANG BOARDS PLAY
VIDEO: MISSION SPECIALIST NICOLE STOTT BOARDS DISCOVERY PLAY
VIDEO: ASTRONAUTS LEAVE CREW QUARTERS BUILDING PLAY | HI-DEF
VIDEO: CREW FINISHES GETTING SUITED UP PLAY | HI-DEF

VIDEO: NARRATED MISSION OVERVIEW MOVIE PLAY | HI-DEF
VIDEO: MEET SHUTTLE DISCOVERY'S ASTRONAUTS PLAY | HI-DEF
VIDEO: NARRATED REVIEW OF SHUTTLE'S PREPARATIONS PLAY | HI-DEF
VIDEO: NARRATED REVIEW OF PAYLOADS' PREPARATIONS PLAY | HI-DEF
VIDEO: THE "COLBERT" TREADMILL PLAY | HI-DEF

VIDEO: MANAGERS EXPLAIN REASON FOR SECOND SCRUB PLAY
VIDEO: WEATHER SCRUBS 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: LAUNCH PAD SERVICE GANTRY ROLLED BACK PLAY | HI-DEF

VIDEO: PRE-LAUNCH INTERVIEW WITH RICK STURCKOW PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH KEVIN FORD PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH PAT FORRESTER PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH JOSE HERNANDEZ PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH DANNY OLIVAS PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH CHRISTER FUGLESANG PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH NICOLE STOTT PLAY

VIDEO: AMERICAN AND EUROPEAN PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: THE LAUNCH COUNTDOWN GETS UNDERWAY PLAY
VIDEO: ASTRONAUTS ARRIVE AT THE CAPE FOR LAUNCH PLAY | HI-DEF
VIDEO: FLIGHT READINESS REVIEW SETS LAUNCH DATE PLAY

VIDEO: SHUTTLE AND STATION PROGRAM UPDATE PLAY
VIDEO: THE STS-128 MISSION OVERVIEW BRIEFING PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY
VIDEO: SHUTTLE PROGRAM MANAGER EXPLAINS FOAM ISSUES PLAY

VIDEO: PAYLOAD BAY DOORS CLOSED FOR FLIGHT PLAY | HI-DEF
VIDEO: MISSION CARGO LOADED ABOARD DISCOVERY PLAY | HI-DEF

VIDEO: CREW TOURS PAD'S CLEANROOM PLAY | HI-DEF
VIDEO: SHUTTLE EVACUATION PRACTICE PLAY | HI-DEF
VIDEO: ASTRONAUTS BOARD DISCOVERY 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: NIGHTTIME APPROACHES IN TRAINING AIRCRAFT PLAY | HI-DEF
VIDEO: TEST-DRIVING EMERGENCY ARMORED TANK PLAY | HI-DEF
VIDEO: INFORMAL CREW NEWS CONFERENCE AT LAUNCH PAD PLAY
VIDEO: ASTRONAUTS ARRIVE FOR PRACTICE COUNTDOWN PLAY

VIDEO: SHUTTLE DISCOVERY ROLLS OUT PAD 39A PLAY | HI-DEF
VIDEO: ORBITER HOISTED FOR MATING TO TANK PLAY | HI-DEF
VIDEO: DISCOVERY MOVED TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: TIME-LAPSE OF DISCOVERY ARRIVING IN VAB PLAY

VIDEO: PAYLOADS DELIVERED TO LAUNCH PAD PLAY | HI-DEF
VIDEO: LEONARDO PUT INTO TRANSPORTER PLAY | HI-DEF
VIDEO: STATION'S NEW AMMONIA TANK PLAY | HI-DEF
VIDEO: MPLM HATCH CLOSED FOR FLIGHT PLAY | HI-DEF
VIDEO: INSIDE SHUTTLE MAIN ENGINE SHOP PLAY | HI-DEF
VIDEO: CREW EQUIPMENT INTERFACE TEST PLAY | HI-DEF
SUBSCRIBE NOW