BY JUSTIN RAY

TUESDAY, OCTOBER 30, 2007

Engineers are scrambling to recover from a solar array hang up that ripped a two-and-a-half-foot tear in one fragile panel as the hinged blanket was pulled from its storage box today. The disheartening, hard-to-reach hang up occurred as the Discovery astronauts were "95 percent of the way to a perfect day," as one NASA official put it, moving the 17-ton P6 solar array truss segment to its permanent mounting point on the far left end of the lab's main power truss.

Read our full story.

1800 GMT (2:00 p.m. EDT)

Spaceflight Now Plus subscribers can watch a movie of the solar array being deployed and the damage occurring. The movie is posted here.

Learn more about Spaceflight Now Plus here.

1740 GMT (1:40 p.m. EDT)

Read our updated story.

1732 GMT (1:32 p.m. EDT)

The solar wing has been turned to give a different view of the damage. An image is posted here.

1706 GMT (1:06 p.m. EDT)

Another half-section has been retracted. The crew had gotten 25 of the 31 sections deployed originally.

1703 GMT (1:03 p.m. EDT)

The half-section retraction did ease some of the tension around the damage area.

1700 GMT (1:00 p.m. EDT)

Two blankets making up one side of the newly installed P6 solar arrays were successfully re-extended today after the 17-ton truss segment was bolted to the far left end of the space station's main power truss. But the astronauts aborted extension of a second set of panels after noticing an apparent guidewire hangup and a jagged tear in one of the two remaining blankets.

Read our full story.

1657 GMT (12:57 p.m. EDT)

Mission Control has asked the crew to retract the array one-half section, or bay. This is designed to lessen the tension on the tear.

1645 GMT (12:45 p.m. EDT)

A closer view of the hole in the blanket is posted here.

1640 GMT (12:40 p.m. EDT)

The crew is taking high-resolution digital images of the array for downlink to the ground. Mission Control says the wing will be rotated to allow further imagery to be taken so engineers can get a full understanding of this tear and the condition of the array.

1637 GMT (12:37 p.m. EDT)

A full view of the solar array is posted here.

1631 GMT (12:31 p.m. EDT)

An image of the tear is posted here.

1627 GMT (12:27 p.m. EDT)

The array is 25 sections, or bays, extended of the wing's total 31-bay length.

1626 GMT (12:26 p.m. EDT)

There appeared to be a snag and then a tear in the blanket resulted.

1625 GMT (12:25 p.m. EDT)

Some significant damage has just occurred on the array blankets. The deploy has been halted.

1622 GMT (12:22 p.m. EDT)

The array deployment has resumed.

1614 GMT (12:14 p.m. EDT)

Deployment has been halted by the crew due to poor visibility with the available camera views. Commander Pam Melroy said the deploy will restart in a few minutes. The array is a little more than 50 percent extended, with no problems encountered on the solar wing so far.

1608 GMT (12:08 p.m. EDT)

Extension of the second solar wing to its full length is now underway.

1554 GMT (11:54 a.m. EDT)

EVA ENDS. Repressurization of the Quest airlock module began at 11:53 a.m. EDT, marking the official end of today's spacewalk by Scott Parazynski and Doug Wheelock.

The EVA lasted 7 hours and 8 minutes, bringing the total time for the three STS-120 spacewalks to 19 hours and 55 minutes.

1543 GMT (11:43 a.m. EDT)

The spacewalkers are back inside the airlock.

1532 GMT (11:32 a.m. EDT)

The first array has reached full deployment! The 2B solar wing on the station's Port 6 truss now stretches 115 feet in length.

1523 GMT (11:23 a.m. EDT)

So far, so good with the deploy.

1520 GMT (11:20 a.m. EDT)

Full deployment of the first P6 truss solar array is underway, commander Pam Melroy reports.

1512 GMT (11:12 a.m. EDT)

Mission Control has given the astronauts a "go" to take over the solar array deployment work and proceed with the unfurling.

1456 GMT (10:56 a.m. EDT)

Both wings have been deployed another section, or bay. Each wing is comprised of 31 bays.

1445 GMT (10:45 a.m. EDT)

Now six hours into the EVA. The astronauts are about to wrap up the spacewalk.

1440 GMT (10:40 a.m. EDT)

The solar wing has been unfurled one section. This is the first step in deploying the array this morning.

1430 GMT (10:30 a.m. EDT)

The two spacewalkers have mounted the spare main bus power unit to the external stowage platform No. 2 outside the space station. The unit was launched on the sidewall of shuttle Discovery's payload bay. With the unit now at the station, it can be used to replace a failed device in the future.

1419 GMT (10:19 a.m. EDT)

Deployment of the first P6 solar wing will begin at 10:40 a.m. EDT.

1407 GMT (10:07 a.m. EDT)

Perched on the end of shuttle Discovery's robot arm, spacewalker Doug Wheelock is carrying a 525-pound main bus power switching unit from the payload bay. The spare unit will be stowed on the station.

1355 GMT (9:55 a.m. EDT)

Spacewalker Scott Parazynski opened up a second solar array rotary joint today, peered inside and told ground controllers he saw no signs of any internal contamination like the metal shavings fellow spacewalker Dan Tani discovered in the space station's right-side rotary joint during a spacewalk Sunday.

Read our full story.

1344 GMT (9:44 a.m. EDT)

Latches holding shut the array blanket boxes on the two P6 solar wings are about to be opened by Mission Control. The wings will be unfurled over the next couple of hours.

1318 GMT (9:18 a.m. EDT)

No metal shavings or debris have been found in the port-side joint, Parazynski reports.

1305 GMT (9:05 a.m. EDT)

Parazynski's next task will be opening a cover on the station's port-side rotary joint for inspections to compare that normally-operating mechanism with the condition seen on the suspect starboard joint. Meanwhile, Wheelock will be moving a spare power switching unit from the shuttle payload bay up to a station external stowage deck.

1253 GMT (8:53 a.m. EDT)

The long photovoltaic radiator has deployed on the Port 6 solar power truss.

1245 GMT (8:45 a.m. EDT)

Today's spacewalk has been underway for four hours now. Scott Parazynski has released cinches holding a retracted radiator on the P6 truss. That radiator will be unfolded via commands from Mission Control.

1200 GMT (8:00 a.m. EDT)

The spacewalkers are working together to remove protective thermal shrouds placed over equipment on the P6 truss. The covers had been installed during the first spacewalk of the mission to shield the hardware during the truss relocation.

1129 GMT (7:29 a.m. EDT)

Four power and data umbilicals between the P5 and P6 truss have been mated. And the station's robot arm has ungrappled P6 following today's installation.

1112 GMT (7:12 a.m. EDT)

P6 was firmly bolted down at 7:10 a.m. Seven years after the Port 6 solar power truss was launched to the space station, the structure has been secured at its permanent location on the outpost.

Later today, the two solar wings of the truss will be redeployed to stretch 240 feet tip-to-tip. One array was retracted during shuttle mission STS-116 last December; the other in June on STS-117.

1105 GMT (7:05 a.m. EDT)

Three of the four corner bolts have been secured. Wheelock will tighten the final bolt as Parazynski begins connecting umbilical lines.

1045 GMT (6:45 a.m. EDT)

Now two hours into today's spacewalk. While Wheelock works to hook up the ground straps at each corner of the truss, Parazynski is engaging the initial torque to bolts that will firmly install the truss.

1032 GMT (6:32 a.m. EDT)

The capture claw has been closed around a bar on the base of P6. Ground straps will be hooked up now between the P5 and P6 trusses.

1023 GMT (6:23 a.m. EDT)

The arm has been limped while the capture claw pulls P6 to its new home on the outer port edge of the space station.

1017 GMT (6:17 a.m. EDT)

Doug Wheelock is driving closed a claw-like device to capture the P6 truss to its attachment point. P6 can't get away now, the spacewalkers joked.

1007 GMT (6:07 a.m. EDT)

Just six inches left to go. The robot arm has been paused again for a final clearance check.

0958 GMT (5:58 a.m. EDT)

The arm has P6 about a foot away from installation while the spacewalkers give an update on alignment.

0947 GMT (5:47 a.m. EDT)

The truss has reached the pre-install position now, about four feet away from its mounting point on the station's P5 truss.

0945 GMT (5:45 a.m. EDT)

Spacewalkers Scott Parazynski and Doug Wheelock are giving visual reports to robot arm operators Stephanie Wilson and Dan Tani as the P6 truss is maneuvered into position for attachment. The arm controllers do not have any good camera views for this truss installation job, making the spacewalkers' calls on alignment most crucial.

0920 GMT (5:20 a.m. EDT)

The spacewalkers are climbing to the far end of the station where the P6 truss will be attached this morning. The station's robot arm has the truss poised to move the final few feet to the installation spot.

0845 GMT (4:45 a.m. EDT)

EVA BEGINS. Scott Parazynski and Doug Wheelock switched their suits to internal battery at 4:45 a.m. EDT, marking the official start time for today's EVA. The airlock has been depressurized and the hatchway is open.

0800 GMT (4:00 a.m. EDT)

Astronauts Scott Parazynski and Doug Wheelock are gearing up for a dramatic spacewalk today to re-attach the 35,000-pound P6 solar array truss after a two-day, 145-foot move, bolting it to the far left end of the space station's main power truss where it will remain for the life of the lab complex. Parazynski also plans to carry out a brief inspection of a second solar array rotary joint to provide more insight into what might be causing contamination in a joint inspected Sunday.

Read our full story.

MONDAY, OCTOBER 29, 2007
2200 GMT (6:00 p.m. EDT)

Flight controllers have adjusted the shuttle Discovery's revised landing time. The latest projections show a deorbit rocket firing at 4:09 a.m. EST on Nov. 7 with landing expected around 5:11 a.m.

1944 GMT (3:44 p.m. EDT)

Flight extended. The Mission Management Team has formally extended space shuttle Discovery's flight by one day, allowing spacewalk No. 4 to be dedicated for inspecting the station truss joint. Landing at Kennedy Space Center is now targeted for about 4 a.m. EDT on Nov. 7.

1900 GMT (3:00 p.m. EDT)

Space station managers today recommended extending the shuttle Discovery's mission by one day to permit a dedicated spacewalk devoted to inspecting an apparently contaminated solar array rotary joint. NASA managers want to track down the source of metallic shavings found inside the joint during a brief inspection Sunday to help figure out what might be needed to fix it.

Read our full story.

0900 GMT (5:00 a.m. EDT)

The space station's robot arm handed a 35,000-pound solar array truss segment to the shuttle's arm today as part of a carefully choreographed, step-by-step procedure to move the stowed arrays to the far left end of the station's main power truss.

Read our full story.

SUNDAY, OCTOBER 28, 2007

Space station engineers are scrambling to determine the source of unexpected debris in a critical solar array rotary joint and considering whether to order an additional, more thorough spacewalk inspection to help figure out what sort of downstream repair work might be necessary.

Read our full story.

1615 GMT (12:15 p.m. EDT)

Astronauts Scott Parazynski and Dan Tani began repressurizing the space station's Quest airlock module today at 12:05 p.m. to officially end a six-hour 33-minute spacewalk, the second of five planned for the shuttle Discovery's mission.

Read our full story.

1606 GMT (12:06 p.m. EDT)

EVA ENDS. Repressurization of the Quest airlock module began at 12:05 p.m. EDT, marking the official end of today's spacewalk by Scott Parazynski and Dan Tani.

The EVA lasted six hours and 33 minutes, bringing the total time for the two STS-120 spacewalks to 12 hours and 47 minutes.

1545 GMT (11:45 a.m. EDT)

The crew is wrapping up this spacewalk and heading back to the airlock now. Replacement of a faulty circuit breaker and electrically hooking up the new robot arm grapple base will be pushed off to an EVA on another day.

1530 GMT (11:30 a.m. EDT)

Astronauts Scott Parazynski and Dan Tani have attached a grapple fixture on the hull of the Harmony module to be used by the space station robotic arm. This arm base had to be launched separately in Discovery's payload bay due to clearance issues.

1450 GMT (10:50 a.m. EDT)

The spacewalkers are getting ready to install an additional robot arm grapple base on the Harmony module.

1432 GMT (10:32 a.m. EDT)

Passing the five-hour mark of the EVA.

1402 GMT (10:02 a.m. EDT)

Now, Tani is reconfiguring cabling inside the space station's Starboard 0 truss segment. The work is being done in preparation to route power from the Port 6 truss when it is installed and its arrays are redeployed on Tuesday.

1348 GMT (9:48 a.m. EDT)

Tani closed up the cover on the rotary joint. He's now configuring equipment that will allow ground controllers to command a radiator deployment on the Starboard 1 truss. Meanwhile, Parazynski continues his work installing handrails and fixtures on the outside hull of the Harmony module.

1317 GMT (9:17 a.m. EDT)

Spacewalker Dan Tani, inspecting a massive solar array rotary joint that has been experiencing high vibration and power usage, reported a large number of metal shavings inside the mechanism after removing a thermal cover and to get a glimpse at the joint's inner workings.

"Great discovery, Dan," spacewalker Scott Parazynski radioed. "I didn't think you'd be able to see anything, but..."

"It's quite clear," Tani said. "There's metal-to-metal scraping, or something, and it's widespread."

"Wow."

Read our full story.

1315 GMT (9:15 a.m. EDT)

Tani has scooped up some samples of the metal filings using tape that can be returned to the ground for analysis.

1258 GMT (8:58 a.m. EDT)

Scott Parazynski is bringing Dan Tani another camera and some sticky tape to take some additional photos and retrieve some of these metail filings he discovered around the starboard-side solar array rotation joint.

1240 GMT (8:40 a.m. EDT)

After removing one of the protective covers surrounding the rotary joint, Tani spotted a large amount of metal shavings around the mechanism.

1230 GMT (8:30 a.m. EDT)

Astronaut Dan Tani is spending some time inspecting the large rotary joint on the starboard 3/Starboard 4 truss segment to look for any signs of what might be causing excessive friction in the mechanism that turns outboard solar panels to track the sun.

1154 GMT (7:54 a.m. EDT)

The station arm with the P6 truss in its grasp has reached a spot off the port side of shuttle Discovery where it will remain for the next day.

1145 GMT (7:45 a.m. EDT)

Astronauts Scott Parazynski and Dan Tani disconnected electrical grounding straps, used power tools to unscrew four bolts and then released a final capture latch holding the 35,000-pound P6 solar array truss segment in place atop the international space station.

Read our full story.

1132 GMT (7:32 a.m. EDT)

Now two hours into today's spacewalk. As the station arm continues slowly maneuvering the P6 truss toward an overnight park position away from the outpost, the spacewalkers have turned their attention to other tasks. Scott Parazynski has begun external outfitting of the newly-installed Harmony module while Dan Tani is doing some inspections of railing around an equipment cart to look for sharp edges that could snag spacewalkers' gloves.

1103 GMT (7:03 a.m. EDT)

The space station's Port 6 solar power module has been detached from the spot it has called home for the past seven years. Launched to the station and activated in November 2000 by the STS-97 shuttle crew, the two solar wings of the P6 truss provided electrical power during the early years of the outpost's life.

Now, the P6 is being relocated to its permanent location outboard on the end of the station's truss backbone. Over the next two days, P6 will be moved by the station and shuttle robotic arms. Its installation to the P5 truss and redeployment of the solar arrays is scheduled for Tuesday morning during the third spacewalk of Discovery's mission.

1100 GMT (7:00 a.m. EDT)

The "go" has been given for the crew inside the station operating the robot arm to demate the P6 truss.

1053 GMT (6:53 a.m. EDT)

All four bolts between the P6 and Z1 trusses have been released by the spacewalkers. A claw-like capture device is still holding the trusses together. That will be disengaged shortly, leaving P6 in the hand of the station robot arm for removal.

1045 GMT (6:45 a.m. EDT)

Two of the four bolts have been released -- one by Parazynski and the other by Tani.

1033 GMT (6:33 a.m. EDT)

Tani is completing the unhooking of all four grounding straps.

1026 GMT (6:26 a.m. EDT)

Releasing of the four corner bolts that have held P6 to the station is underway.

1015 GMT (6:15 a.m. EDT)

Parazynski and Tani have moved swiftly through their work to disconnect and cap off the nine umbilicals running between the P6 and Z1 trusses atop the space station. A series of ground straps need to be removed next.

1000 GMT (6:00 a.m. EDT)

The spacewalkers have made their way up to the Port 6 truss to begin removing nine data and power umbilical cables running from the Z1 truss.

0932 GMT (5:32 a.m. EDT)

EVA BEGINS. Scott Parazynski and Dan Tani switched their suits to internal battery at 5:32 a.m. EDT, marking the official start time for today's EVA. The airlock has been depressurized and the hatchway is open.

Meanwhile, the station's robot arm has grappled the Port 6 truss in advance of the spacewalkers disconnecting cabling and unbolting the massive structure this morning.

0815 GMT (4:15 a.m. EDT)

Astronauts Scott Parazynski and Dan Tani suited up and made final preparations for a dramatic six-and-a-half-hour spacewalk today to disconnect a 35,000-pound solar array segment for a two-day move to the far left end of the space station's main power truss.

Read our full story.

SATURDAY, OCTOBER 27, 2007
1305 GMT (9:05 a.m. EDT)

Space station commander Peggy Whitson and Italian astronaut Paolo Nespoli opened the hatch to the newly installed Italian-built Harmony module at 8:24 a.m. today and floated into the roomy, brightly lighted room that will serve as the gateway to European and Japanese research modules scheduled for launch late this year and early next.

Read our full story.

FRIDAY, OCTOBER 26, 2007

NASA managers said today's installation of the new Harmony module on the space station, and work by two spacewalking astronauts to prepare the P6 truss for its long-awaited detachment during a second spacewalk Sunday, went "extremely well." A task added to Sunday's EVA is a visual inspection of the massive rotary joint on the right side of the station's main power truss.

Read our full story.

1645 GMT (12:45 p.m. EDT)

Astronauts Scott Parazynski and Doug Wheelock, after waiting out a routine ammonia decontamination procedure, repressurized the space station's airlock today to officially close out a successful six-hour 14-minute spacewalk. A half hour earlier, at 11:38 a.m., the new 31,500-pound Harmony module was attached to its temporary home on the left side of the central Unity module to accomplish one of the major objectives of the shuttle Discovery's mission.

Read our full story.

1616 GMT (12:16 p.m. EDT)

EVA ENDS. Repressurization of the Quest airlock module began at 12:16 p.m. EDT, marking the official end of today's spacewalk by Scott Parazynski and Doug Wheelock. The EVA lasted six hours and 14 minutes.

1610 GMT (12:10 p.m. EDT)

Having released its grip on the Harmony module, the station robot arm is now backing away.

1600 GMT (12:00 p.m. EDT)

The spacewalkers are back in the airlock. Before full repressurization can begin, however, the crew will be completing some additional ammonia contamination checks as a precaution.

1557 GMT (11:57 a.m. EDT)

Electrically-driven bolts have been engaged to firmly join the Harmony connecting module to the space station, the crew reports. Harmony has been attached to the station's Unity node where it will remain for a couple of weeks until the Expedition 16 crew installs a docking port and relocates the new module to its final destination on the front-end of the Destiny laboratory module.

1540 GMT (11:40 a.m. EDT)

The second stage of capture now confirmed.

1535 GMT (11:35 a.m. EDT)

The first stage of capture between Harmony and the station has occurred.

Meanwhile, the spacewalkers are back at the airlock module conducting a tool and equipment inventory. They have successfully completed the day's EVA to-do list.

1522 GMT (11:22 a.m. EDT)

Harmony is nearing the final few feet for installation to the station.

1500 GMT (11:00 a.m. EDT)

Astronauts Stephanie Wilson and Dan Tani, operating the space station's robot arm, carefully pulled the 31,500-pound Harmony module from the shuttle Discovery's cargo bay today for attachment to the international lab complex. Spectacular video beamed down from the shuttle showed the massive module being slowly maneuvered above the spaceplane over toward the left side of the outpost where it will be installed on the central Unity module.

Read our full story.

1450 GMT (10:50 a.m. EDT)

The spacewalkers are working together to complete the two-man job of installing a large thermal shroud over a retracted radiator on the Port 6 truss structure.

1429 GMT (10:29 a.m. EDT)

Wheelock did not see any signs of ammonia contamination.

1422 GMT (10:22 a.m. EDT)

Doug Wheelock is making a precautionary inspection of Scott Parazynski's to look for any contamination from a few ammonia crystals seen escaping from one of the fluid lines being disconnected between the Z1 and P6 trusses.

1402 GMT (10:02 a.m. EDT)

Now passing the four-hour mark in today's EVA. Work continues at the P6 truss for the spacewalkers.

With astronauts Stephanie Wilson and Dan Tani at the controls, the space station's Canadian-made robot arm is gently maneuvering the Italian-built Harmony connecting module toward its attachment port on the international outpost.

1355 GMT (9:55 a.m. EDT)

Up on top of the space station, Scott Parazynski is disconnecting a series of fluid lines between the Z1 and P6 trusses while Doug Wheelock prepares thermal covers to be installed around components on P6.

1346 GMT (9:46 a.m. EDT)

Harmony is now clear of the payload bay.

1340 GMT (9:40 a.m. EDT)

With the restraint latches released to free Harmony from the shuttle, the station robot arm is slowly hoisting Harmony out of the payload bay.

1330 GMT (9:30 a.m. EDT)

Astronaut Doug Wheelock, anchored to the end of the space station's robot arm, manually carried a large S-band antenna assembly down to a stowage location in the shuttle Discovery's cargo bay for return to Earth. Wheelock and Scott Parazynski then tethered a robot arm grapple fixture to the new Harmony module and prepared it for attachment to the international space station.

Read our full story.

1315 GMT (9:15 a.m. EDT)

Harmony has been grappled by the station robot arm in advance of the module's unberthing from the payload bay. Meanwhile, the spacewalkers are headed up to the Port 6 solar array truss to remove fluid lines and install some shrouds over a radiator and electronics boxes in preparation for the structure's relocation this weekend.

1259 GMT (8:59 a.m. EDT)

The spacewalkers have completed their part in readying Harmony to move from the space shuttle to the space station. Now it's up to the station's robot arm to reach down and pull the module out of the payload bay.

1240 GMT (8:40 a.m. EDT)

Protective covers on Harmony's attachment port that will mate the module to the station have been taken off by the spacewalkers. And heaters are being deactivated so that the power cable running from the shuttle to the module can be disconnected.

1202 GMT (8:02 a.m. EDT)

Preparing the Harmony module for removal from the payload bay and today's installation to the space station is the focus for the astronauts now as the spacewalk passes the two-hour mark.

1125 GMT (7:25 a.m. EDT)

The spacewalkers have mounted the S-band antenna assembly to the starboard sidewall of space shuttle Discovery's payload bay. The communications device will ride home on the shuttle for repair and a later launch back to the station.

1055 GMT (6:55 a.m. EDT)

Perched on the end of the space station's robot arm, rookie astronaut Doug Wheelock is carrying the S-band antenna in his hands from the station's Z1 truss down to shuttle Discovery's payload bay. Spacewalker Scott Parazynski has made his way to the shuttle to help receive the antenna.

1032 GMT (6:32 a.m. EDT)

Now 30 minutes into today's spacewalk. The crew has removed the S-band antenna assembly from the space station. They will be taking it down to the shuttle payload bay where the antenna will be stowed for return to Earth.

1002 GMT (6:02 a.m. EDT)

EVA BEGINS. The airlock has been depressurized and the outer hatchway has swung open. The spacewalkers switched their suits to internal battery at 6:02 a.m. EDT, marking the official start time for today's EVA by Scott Parazynski and Doug Wheelock.

0930 GMT (5:30 a.m. EDT)

Astronauts Scott Parazynski and Doug Wheelock are gearing up for a six-and-a-half hour spacewalk today to help install the new Harmony module on the international space station. They also plan to retrieve an S-band antenna assembly for return to Earth and prepare a solar array truss segment for relocation later in the mission.

Read our full story.

THURSDAY, OCTOBER 25, 2007

The shuttle Discovery appears to have come through its launch and climb to space in good shape with no major heat shield problems and no need for any additional, "focused" inspections before undocking, NASA managers said Thursday.

Read our full story.

1715 GMT (1:15 p.m. EDT)

Commander Pam Melroy deftly guided the shuttle Discovery to a "picture-perfect" docking with the international space station today, setting the stage for the first of five spacewalks Friday to install a new module, move a huge solar array truss and test a potentially valuable heat shield repair technique.

Read our full story.

1440 GMT (10:40 a.m. EDT)

HATCHES OPEN. The hatchway between Discovery and the space station was opened at 10:39 a.m. EDT, and the shuttle crew is being welcomed aboard the outpost now.

1251 GMT (8:51 a.m. EDT)

The docking ring between the two craft has been retracted into Discovery's Orbiter Docking System, pulling the station to a tight mating. The hooks and latches are driving shut to firmly connect the two spacecraft.

Pressure and leak checks will be performed by the crews before the hatchway is opened.

1240 GMT (8:40 a.m. EDT)

CONTACT AND CAPTURE! Discovery has arrived at the space station to install the Harmony connecting module and relocate the Port 6 solar array power truss.

The relative motions of the shuttle and station will be allowed to damp out over the next few minutes by the spring-loaded docking system. Later, the hooks and latches will be closed to firmly join the two craft and Discovery's Orbiter Docking System docking ring will be retracted to form a tight seal.

The opening of hatches between the station and shuttle is expected in about 90 minutes. That will be followed by a welcoming ceremony and safety briefing.

1238 GMT (8:38 a.m. EDT)

The distance to docking is now 10 feet.

1237 GMT (8:37 a.m. EDT)

Now 15 feet separating the shuttle from the station. Discovery's thrusters are programmed to fire in a post-contact maneuver to force the two docking ports together. That procedure is being armed.

1235 GMT (8:35 a.m. EDT)

The final approach beginning. The alignment between docking ports on Discovery and the space station is acceptable and no "fly out" maneuver by the shuttle is necessary.

1231 GMT (8:31 a.m. EDT)

Discovery has closed to within 50 feet of the space station as the spacecraft near an orbital sunrise.

1221 GMT (8:21 a.m. EDT)

About 125 feet left to go.

1214 GMT (8:14 a.m. EDT)

Mission Control estimates docking time will be about 8:45 a.m., roughly 10 minutes late based on the shuttle's approach rate.

1208 GMT (8:08 a.m. EDT)

Now about 250 feet from docking. Discovery is closing at about two-tenths of a foot per second.

1200 GMT (8:00 a.m. EDT)

The shuttle's crew has been given a "go" for docking.

1159 GMT (7:59 a.m. EDT)

Discovery has reached the point directly in front of the station along the imaginary line called the velocity vector, or +V bar. The shuttle is about 390 feet from the station.

1150 GMT (7:50 a.m. EDT)

Discovery is beginning the arc from the point beneath the station to a point roughly 400 feet in front of the complex to align with the docking port on the Destiny module. Docking is less than 45 minutes away.

1143 GMT (7:43 a.m. EDT)

The pitch maneuver has been completed. Discovery is back in the orientation where it started, with the payload bay looking up at the station.

1140 GMT (7:40 a.m. EDT)

The main engine nozzles of Discovery are facing the station now as the shuttle points its tail upward.

1139 GMT (7:39 a.m. EDT)

This 360-degree, nose-first pirouette by Discovery gives the station crew about 100 seconds of quality photography time to snap detailed pictures of the orbiter's black tiles in the search for any launch impact damage.

1138 GMT (7:38 a.m. EDT)

The formal photo-taking period has started for the station crew, now that the shuttle has rotated its underside in view of the laboratory complex.

1137 GMT (7:37 a.m. EDT)

Discovery is nose-up facing the station as the two craft fly more than 200 miles above the Atlantic.

1134 GMT (7:34 a.m. EDT)

The rendezvous pitch maneuver -- the 360-degree flip -- is beginning. The shuttle is the under the control of commander Pam Melroy, who is flying the ship from the aft flight deck.

1125 GMT (7:25 a.m. EDT)

The shuttle is about 1,000 feet from the station. All has gone smoothly in this morning's rendezvous.

At a distance of about 600 feet directly below the station, commander Pam Melroy will carry out a slow 360-degree rendezvous pitch maneuver, or RPM, that will point the belly of the shuttle at the station.

As the shuttle's underside rotates into view, the station's crew will photograph Discovery's belly with handheld digital cameras equipped with 400- and 800-millimeter lenses.

The 800mm images should provide one-inch resolution for examination of landing gear door and external tank umbilical door seals. The 400mm will yield three-inch resolution.

After completing the RPM maneuver, Discovery will fly directly ahead of the space station with the shuttle's nose facing deep space and its cargo bay pointed at the lab complex. Then Melroy will guide the spacecraft to a docking with a pressurized mating adapter attached to the Destiny lab module.

1015 GMT (6:15 a.m. EDT)

Trailing the international space station by about 9.2 miles, shuttle commander Pam Melroy and pilot George Zamka fired Discovery's maneuvering rockets today at 5:55 a.m. to kick off the final stages of a two-day rendezvous procedure that began with launch Tuesday. If all goes well, Melroy will guide Discovery to a docking with pressurized mating adapter No. 2 on the front of the lab complex around 8:33 a.m.

Read our full story.

0956 GMT (5:56 a.m. EDT)

TI burn. The shuttle has performed the 12-second Terminal Initiation burn to begin the final phase of today's rendezvous. The brief firing used the left Orbital Maneuvering System engine on the tail of Discovery.

The TI burn puts the shuttle on a trajectory to directly intercept the orbiting station over the next orbit and a half. This burn is the latest in a series of maneuvers performed by Discovery during its two days of chasing the station since launch Tuesday.

Docking is anticipated at 8:33 a.m. EDT.

WEDNESDAY, OCTOBER 24, 2007

The shuttle Discovery's foam-covered external fuel tank performed well during launch, NASA officials said Wednesday, shedding only a half-dozen pieces of insulation - all well after the period when such debris can pose an impact hazard - with no signs of damage to the orbiter's heat shield.

Read our full story.

1615 GMT (12:15 p.m. EDT)

The shuttle Discovery's crew used a laser scanner and a high-resolution digital camera on the end of a long boom today to inspect the ship's reinforced carbon carbon nose cap and wing leading edge panels in a now-standard exercise for post-Columbia crews.

Today's scan took on a bit of added significance because of pre-launch concern over subtle degradation in a protective coating on three of the 44 wing leading edge panels, which experience some of the most extreme heating during re-entry.

Read our full story.

1550 GMT (11:50 a.m. EDT)

The inspections using the Orbiter Boom Sensor System have been completed for today. There were no obvious signs of impact damage to Discovery's critical wing leading edge panels or nose cap. But detailed analysis of the data and imagery will be performed by engineers on the ground before NASA can declare the heat shield in good shape.

Once the sensor boom is stowed back in the payload bay, the crew will turn its attention to preparing for tomorrow's docking to the station. The astronauts begin an eight-hour sleep period at 5:38 p.m. EDT.

1315 GMT (9:15 a.m. EDT)

Inspections of the orbiter are continuing aboard space shuttle Discovery. Scans of the starboard wing using the Orbiter Boom Sensor System have been completed. The nose cap checks are underway now. The port wing inspections are still to come today.

This is a multi-hour job to survey the shuttle to look for any signs of launch damage. The precautionary safety inspection has become a standard activity for all post-Columbia shuttle crews.

1000 GMT (6:00 a.m. EDT)

The Discovery astronauts are working through a busy day in space today, setting up a critical heat shield inspection and preparing the shuttle for docking Thursday with the international space station.

Commander Pam Melroy, pilot George Zamka, flight engineer Stephanie Wilson, Italian astronaut Paolo Nespoli, spacewalkers Scott Parazynski, Doug Wheelock and new space station crew member Dan Tani were awakened at 1:39 a.m. for their first full day in orbit. Today's wakeup music beamed up from mission control was a recording of "Lord of the Dance" performed by John Langstaff.

Read our full story.

TUESDAY, OCTOBER 23, 2007

The shuttle Discovery, carrying seven astronauts and a critical connecting module for the international space station, roared to life and rocketed into orbit today, kicking off a high-stakes five-spacewalk mission considered by many the most complex orbital construction work ever attempted.

Read our full story.

1618 GMT (12:18 p.m. EDT)

T+plus 40 minutes, 30 seconds. The twin Orbital Maneuvering System engines on the tail of Discovery have been fired successfully to propel the shuttle the rest of the way to orbit. The burn boosted the shuttle from a 136 by 36 mile orbit into a safe 141 by 121 mile orbit.

1547 GMT (11:47 a.m. EDT)

T+plus 9 minutes, 30 seconds. It was a nominal MECO. A quick boost from the Orbital Maneuvering System engines is not required to reach the planned preliminary sub-orbital trajectory.

1547 GMT (11:47 a.m. EDT)

T+plus 8 minutes, 50 seconds. The emptied external tank has been jettisoned from the belly of space shuttle Discovery. The tank will fall back into the atmosphere where it will burn up harmlessly.

1546 GMT (11:46 a.m. EDT)

T+plus 8 minutes, 35 seconds. MECO. Main Engine Cutoff confirmed! Speeding along at five miles per second above the Atlantic Ocean. Discovery is in space to deliver the Harmony module to the station.

1546 GMT (11:46 a.m. EDT)

T+plus 7 minutes, 45 seconds. The main engines are beginning to throttle down to ensure the shuttle does not experience forces greater than 3 g's as it continues to accelerate prior to engine shutdown.

1545 GMT (11:45 a.m. EDT)

T+plus 7 minutes, 20 seconds. Single engine press 104. The shuttle can reach orbit on the power from a single main engine should two fail at this point. But all three continue to fire properly.

1545 GMT (11:45 a.m. EDT)

T+plus 6 minutes, 45 seconds. Discovery is 66 miles in altitude, traveling at 10,700 mph.

1544 GMT (11:44 a.m. EDT)

T+plus 6 minutes, 30 seconds. "Press to MECO" Discovery can now achieve a safe orbit on two engines. All three remain in good shape.

1544 GMT (11:44 a.m. EDT)

T+plus 6 minutes. The shuttle has started rolling to a heads-up position to improve communications with the TDRS satellite network.

1543 GMT (11:43 a.m. EDT)

T+plus 5 minutes, 30 seconds. "Press to ATO". Discovery can reach an orbit, albeit a low orbit, on two engines should one shut down now. But all three powerplants are still running just fine.

1542 GMT (11:42 a.m. EDT)

T+plus 4 minutes, 30 seconds. Discovery will be tripling its speed in the next four minutes to reach orbital velocity of 17,500 mph.

1542 GMT (11:42 a.m. EDT)

T+plus 3 minutes, 57 seconds. Negative return. The shuttle has passed the point where Discovery could turn around and make an emergency landing at Kennedy Space Center in the event of a main engine problem. Landing sites in France and Spain are now available to Discovery in the unlikely event an abort occurs during the remainder of this evening's launch.

1542 GMT (11:42 a.m. EDT)

T+plus 3 minutes, 45 seconds. Discovery is 57 miles in altitude, 124 miles northeast of the launch pad, traveling at 4,600 mph.

1541 GMT (11:41 a.m. EDT)

T+plus 2 minutes, 50 seconds. Commander Pam Melroy just received the "Two-engine TAL" call from CAPCOM Terry Virts in Mission Control. The call means Discovery can now reach the Transatlantic Abort Landing site in Moron, Spain if one main engine fails. However, all three engines continue to burn normally.

1540 GMT (11:40 a.m. EDT)

T+plus 2 minutes, 30 seconds. The twin Orbital Maneuvering System engines on the ship's tail have ignited to provide an extra boost in thrust in addition to Discovery's three main engines.

1540 GMT (11:40 a.m. EDT)

T+plus 2 minutes, 20 seconds. Guidance is converging as programmed. Discovery's engine nozzles are swiveling to steer the ship toward a precise point for main engine cutoff about six minutes from now.

1540 GMT (11:40 a.m. EDT)

T+plus 2 minutes, 10 seconds. The twin solid rocket boosters have burned out and jettisoned. The shuttle continues its streak toward space on the power generated by the three liquid-fueled main engines.

1539 GMT (11:39 a.m. EDT)

T+plus 90 seconds. The space shuttle now weighs just half of what it did at liftoff. The solid rocket boosters are burning 11,000 pounds of propellant every second. The main engines are guzzling a half-ton of liquid fuel per second from the external tank.

1539 GMT (11:39 a.m. EDT)

T+plus 70 seconds. Discovery's three main engines have revved up to their 104 percent power setting. And Mission Control has given the "go at throttle up" call.

1539 GMT (11:39 a.m. EDT)

T+plus 60 seconds. One minute into the flight. Discovery is traveling more than 1,000 miles per hour as the main engines and twin solid rockets continue to generate nearly 7 million pounds of thrust.

1538 GMT (11:38 a.m. EDT)

T+plus 35 seconds. Discovery's three liquid-fueled main engines are easing back to two-thirds throttle to reduce the aerodynamic stresses on the vehicle as it powers through the dense lower atmosphere and breaks the sound barrier.

1538 GMT (11:38 a.m. EDT)

T+plus 20 seconds. Discovery has rolled on course for a 51.6 degree inclination orbit to rendezvous with the space station on Thursday morning.

1538:19 GMT (11:38:19 a.m. EDT)

LIFTOFF! Liftoff of space shuttle Discovery with the space station's Harmony connecting module, the global gateway to international science!

1537:48 GMT (11:37:48 a.m. EDT)

T-minus 31 seconds. AUTO SEQUENCE START! The handoff has occurred from the Ground Launch Sequencer to the space shuttle. Discovery's computers now controlling.

In the next few seconds, the solid rocket booster hydraulic steering system will be started, the orbiter's body flap and speed brake moved to their launch positions, the firing chain armed. Main engine ignition begins at T-minus 6.6 seconds.

1537:19 GMT (11:37:19 a.m. EDT)

T-minus 1 minute. Computers are verifying that the main engines are ready for ignition. Sound suppression water system is armed. The system will activate at T-minus 16 seconds to suppress the sound produced at launch. And the residual hydrogen burn ignitors are armed. They will be fired at T-minus 10 seconds to burn off hydrogen gas from beneath the main engine nozzles.

Shortly, the external tank strut heaters will be turned off; Discovery will transition to internal power; the liquid oxygen and liquid hydrogen outboard fill and drain valves will be closed; the payload bay vent doors will be positioned for the launch; and the gaseous oxygen vent arm will be verified fully retracted.

1536:19 GMT (11:36:19 a.m. EDT)

T-minus 2 minutes. The astronauts are being instructed to close and lock the visors on their launch and entry helmets.

At T-minus 1 minute, 57 seconds the replenishment to the flight load of liquid hydrogen in the external tank will be terminated and tank pressurization will begin.

1535:49 GMT (11:35:49 a.m. EDT)

T-minus 2 minutes, 30 seconds. The external tank liquid oxygen vent valve has been closed and pressurization of the LOX tank has started.

Discovery's power-producing fuel cells are transfering to internal reactants. The units will begin providing electricity for the mission beginning at T-50 seconds.

In the next few seconds, the gaseous oxygen vent hood will be removed from atop the external tank. Verification that the swing arm is fully retracted will be made by the ground launch sequencer at the T-minus 37 second mark.

1535:19 GMT (11:35:19 a.m. EDT)

T-minus 3 minutes. Orbiter steering check is now complete; the main engine nozzles are in their start positions.

1534:49 GMT (11:34:49 a.m. EDT)

T-minus 3 minutes, 30 seconds. The main engine nozzles now being moved through a computer controlled test pattern to demonstrate their readiness to support guidance control during launch today.

1534:19 GMT (11:34:19 a.m. EDT)

T-minus 4 minutes. Activation of the APUs is complete. The three units are up and running normally.

And the final helium purge sequence is underway in the main propulsion system. This procedure readies fuel system valves for engine start. In the next few seconds, the aerosurfaces of Discovery will be run through a pre-planned mobility test to ensure readiness for launch. This is also a dress rehearsal for flight of the orbiter's hydraulic systems.

1533:19 GMT (11:33:19 a.m. EDT)

T-minus 5 minutes. The "go" has been given for for Auxiliary Power Unit start. Pilot George Zamka is now flipping three switches in Discovery's cockpit to start each of the three APU's. The units, located in the aft compartment of Discovery, provide the pressure needed to power the hydraulic systems of the shuttle. The units will be used during the launch and landing phases of the mission for such events as moving the orbiter's aerosurfaces, gimbaling the main engine nozzles and deploying the landing gear.

Over the course of the next minute, the orbiter's heaters will be configured for launch by commander Pam Melroy, the fuel valve heaters on the main engines will be turned off in preparation for engine ignition at T-6.6 seconds and the external tank and solid rocket booster safe and arm devices will be armed.

1532:49 GMT (11:32:49 a.m. EDT)

T-minus 5 minutes, 30 seconds. APU pre-start is complete and the units are ready for activation. The orbiters flight data recorders have gone into the record mode to collect measurements of shuttle systems performance during flight.

1532:19 GMT (11:32:19 a.m. EDT)

T-minus 6 minutes. Pilot George Zamka has been asked by the orbiter test conductor to pre-start the orbiter Auxiliary Power Units. This procedure readies the three APU's for their activation after the countdown passes T-minus 5 minutes.

1530:49 GMT (11:30:49 a.m. EDT)

T-minus 7 minutes, 30 seconds. The Ground Launch Sequencer has started pulling the orbiter access arm away from the crew hatch on the port side of the vehicle. The arm was the passage way for the astronauts to board Discovery a few hours ago. The arm can be re-extended very quickly should the need arise later in the countdown.

1530:19 GMT (11:30:19 a.m. EDT)

T-minus 8 minutes and counting. Pilot George Zamka has flipped the switches in the cockpit of Discovery to directly connect the three onboard fuel cells with the essential power buses. Also, the stored program commands have been issued to the orbiter.

1529:19 GMT (11:29:19 a.m. EDT)

T-minus 9 minutes and counting! The Ground Launch Sequencer is now actively running this final phase of this morning's countdown to launch space shuttle Discovery.

1528:19 GMT (11:28:19 a.m. EDT)

Countdown clock will resume in one minute.

Once the countdown picks up, the Ground Launch Sequencer will be initiated. The computer program is located in a console in the Firing Room of the Complex 39 Launch Control Center. The GLS is the master of events through liftoff. During the last 9 minutes of the countdown, the computer will monitor as many as a thousand different systems and measurements to ensure that they do not fall out of any pre-determine red-line limits. At T-minus 31 seconds, the GLS will hand off to the onboard computers of Discovery to complete their own automatic sequence of events through the final half minute of the countdown.

1527 GMT (11:27 a.m. EDT)

NASA launch director Mike Leinbach has conducted his poll and given approval to resume the countdown for an on-time liftoff at 11:38 a.m. this morning!

1525 GMT (11:25 a.m. EDT)

The final readiness poll by the NASA test director Steve Payne confirms there are no technical issues being addressed. The Range also reports "go" on the local weather. And Mission Control is ready for the flight.

1523 GMT (11:23 a.m. EDT)

The Mission Management Team has been polled and all members are "go" for launch.

1521 GMT (11:21 a.m. EDT)

The small area of ice on the external tank's liquid hydrogen umbilical has been deemed not a constraint to launch. And the weather is still "go" for launch.

1519 GMT (11:19 a.m. EDT)

Ten minutes are remaining in this built-in hold. Final readiness polls will be conducted over the next few minutes.

1508 GMT (11:08 a.m. EDT)

Now 30 minutes from launch of Discovery. Liftoff remains set for 11:38 a.m. EDT.

1505 GMT (11:05 a.m. EDT)

The ice discussions continue. The buildup does, in fact, appear to be dissipating.

1500 GMT (11:00 a.m. EDT)

The solid rocket booster retrieval ships are positioned 140 nautical miles northeast of the launch pad, off the coast of Jacksonville, to await Discovery's liftoff this morning. The ships will recover the twin boosters after they parachute into the Atlantic Ocean. The motor casings are towed back to the Cape to begin the process of preparing the boosters for reuse.

1444 GMT (10:44 a.m. EDT)

T-minus 9 minutes and holding. Countdown clocks have gone into the planned 45-minute, 19-second built-in hold. Today's launch remains set for 11:38:19 a.m. EDT, pending the ice buildup concern. The ice appears to be diminishing in size, a NASA spokesman says. Weather remains "go" right now.

1440 GMT (10:40 a.m. EDT)

The Main Propulsion System helium system is being reconfigured by pilot George Zamka. Soon the gaseous nitrogen purge to the aft skirts of the solid rocket boosters will be started.

1438 GMT (10:38 a.m. EDT)

Now one hour away from launch of Discovery.

Pilot George Zamka is configuring the displays inside Discovery's cockpit for launch while commander Pam Melroy enables the abort steering instrumentation.

1435 GMT (10:35 a.m. EDT)

The inspection team has completed its special examination of the ice buildup around the external fuel tank liquid hydrogen outboard umbilical. They'll be briefing mission managers back at the launch control center on the situation to determine if this a constraint to liftoff today.

1433 GMT (10:33 a.m. EDT)

T-minus 20 minutes and counting. The countdown has resumed after a 10-minute hold. Clocks will tick down for the next 11 minutes to T-minus 9 minutes where the final planned hold is scheduled to occur. The hold length will be adjusted to synch up with today's preferred launch time of 11:38:19 a.m.

Discovery's onboard computers are now transitioning to the Major Mode-101 program, the primary ascent software. Also, engineers are dumping the Primary Avionics Software System (PASS) onboard computers. The data that is dumped from each of PASS computers is compared to verify that the proper software is loaded aboard for launch.

1427 GMT (10:27 a.m. EDT)

The Orbiter Closeout Crew is preparing to leave the pad now.

1423 GMT (10:23 a.m. EDT)

T-minus 20 minutes and holding. The countdown has paused for a 10-minute built-in hold. Launch is scheduled for 11:38:19 a.m. EDT.

During this built-in hold, all computer programs in Firing Room 4 of the Complex 39 Launch Control Center will be verified to ensure that the proper programs are available for the countdown; the landing convoy status will be verified and the landing sites will be checked to support an abort landing during launch today; the Inertial Measurement Unit preflight alignment will be verified completed; and preparations are made to transition the orbiter onboard computers to Major Mode 101 upon coming out of the hold. This configures the computer memory to a terminal countdown configuration.

1411 GMT (10:11 a.m. EDT)

The official target liftoff time has been adjusted a few seconds to 11:38:19 a.m. EDT.

1405 GMT (10:05 a.m. EDT)

The ground pyro initiator controllers (PICs) are scheduled to be powered up around this time in the countdown. They are used to fire the solid rocket hold-down posts, liquid oxygen and liquid hydrogen tail service mast and external tank vent arm system pyros at liftoff and the space shuttle main engine hydrogen gas burn system prior to engine ignition.

The shuttle's two Master Events Controllers are being tested. They relay the commands from the shuttle's computers to ignite, and then separate the boosters and external tank during launch.

1358 GMT (9:58 a.m. EDT)

The inspection team has arrived at the pad. An image of the ice taken by a launch pad video camera is available here.

1348 GMT (9:48 a.m. EDT)

The inspection team that have surveyed space shuttle Discovery earlier this morning is being dispatched back to pad 39A to get an upclose look at the ice around the hydrogen umbilical. The ice appears to be about four inches by 1.5 inches, with a thickness of 3/8ths of inch, NASA says.

1348 GMT (9:48 a.m. EDT)

The hatch is confirmed to be closed and latched.

1343 GMT (9:43 a.m. EDT)

Now passing the T-minus 1 hour mark in the countdown. Two scheduled holds are planned at T-minus 20 minutes and T-minus 9 minutes, leading to the target liftoff time of 11:38 a.m., if this ice formation issue on the external tank is deemed not a flight safety concern.

Meanwhile, the final pre-flight alignment of Discovery's guidance system inertial measurement units is underway.

1337 GMT (9:37 a.m. EDT)

The "go" has been given to close Discovery's crew module hatch.

1329 GMT (9:29 a.m. EDT)

An area of ice has formed around the liquid hydrogen umbilical line that connected to space shuttle Discovery. Engineers and managers are discussing the situation to determine if this is a safety constraint for launch.

1313 GMT (9:13 a.m. EDT)

T-minus 90 minutes and counting. Countdown clocks continue to tick down to T-minus 20 minutes where the next hold is planned. Countdown activities remain on track for liftoff at 11:38 a.m.

At this point in the count, the Ground Launch Sequencer software that will control the final nine minutes of the countdown has been initialized. Also, the solid rocket boosters' gas generator heaters in the hydraulic power units are turned on, the aft skirt gaseous nitrogen purge is starting and the rate gyro assemblies (RGAs) are being activated. The RGAs are used by the orbiter's navigation system to determine rates of motion of the boosters during the first stage of flight.

1308 GMT (9:08 a.m. EDT)

The final crewmember just boarded Discovery. Stephanie Wilson serves as mission specialist No. 2 and flight engineer on Discovery. She will ride in the flight deck's aft-center seat.

Read her biography here.

1256 GMT (8:56 a.m. EDT)

Doug Wheelock is mission specialist No. 3 for Discovery. He is climbing to the flight deck's aft-right seat.

Read his biography here.

1245 GMT (8:45 a.m. EDT)

Astronaut Dan Tani is taking the center seat on the middeck. He is headed for the space station to join the Expedition 16 crew.

Read his biography here.

1238 GMT (8:38 a.m. EDT)

Three hours and counting until liftoff time. Weather remains "go" at this time and no technical problems are being worked.

1234 GMT (8:34 a.m. EDT)

Scott Parazynski serves as mission specialist No. 1 on Discovery's STS-120 flight. He just entered the orbiter to take the middeck's left seat.

Read his biography here.

1232 GMT (8:32 a.m. EDT)

Pilot George Zamka, is making his way to the flight deck's front-right seat.

Read his biography here.

1223 GMT (8:23 a.m. EDT)

Italian astronaut Paolo Nespoli, the mission specialist No. 4 for STS-120, has boarded Discovery to take the middeck's right-side seat.

Read his biography here.

1219 GMT (8:19 a.m. EDT)

Commander Pam Melroy is the first astronaut to board the shuttle. She is taking the forward-left seat on the flight deck.

You can read her biography here.

1205 GMT (8:05 a.m. EDT)

Discovery's crew arrived at launch pad 39A at 8:05 a.m. The AstroVan came to a stop on the pad surface near the Fixed Service Structure tower elevator that will take the seven-person crew to the 195-foot level to begin boarding the shuttle.

1158 GMT (7:58 a.m. EDT)

The AstroVan is passing the 52-story Vehicle Assembly Building where Discovery was attached to its external tank and solid rocket boosters and the adjacent Launch Control Center en route to the pad.

1148 GMT (7:48 a.m. EDT)

With commander Pam Melroy leading the way, the seven-person astronaut crew just departed the Kennedy Space Center crew quarters to board the silver AstroVan for the 20-minute ride from the Industrial Area to launch pad 39A on the edge of the Atlantic Ocean.

Learn more about the astronauts here.

1143 GMT (7:43 a.m. EDT)

T-minus 3 hours and counting. The countdown clocks are ticking again after the planned two-and-a-half-hour built-in hold. Clocks will proceed to T-minus 20 minutes when the next hold is scheduled. A final hold occurs at the T-minus 9 minute mark to synch up with the 11:38 a.m. EDT launch time.

1127 GMT (7:27 a.m. EDT)

The crew has donned the day-glow orange launch and entry partial pressure spacesuits. After final adjustments and pressure checks, the astronauts will depart the suitup room and take the elevator down to the ground level of the Operations and Checkout Building to board the AstroVan for the trip to launch pad 39A around 7:48 a.m.

1110 GMT (7:10 a.m. EDT)

The Final Inspection Team is performing its observations of Discovery this afternoon.

The team is responsible for checking the shuttle and launch pad one last time prior to liftoff. The team is comprised of engineers and safety officials from NASA, United Space Alliance and tank-builder Lockheed Martin. At the conclusion of their two-hour tour-of-duty, the team will have walked up and down the entire fixed service structure and mobile launcher platform.

The team is on the lookout for any abnormal ice or frost build-up on the vehicle and integrity of the external tank foam insulation.

The team uses a portable infrared scanner that gathers temperature measurements on the surface area of the shuttle and can spot leaks. The scanner will be used to obtain temperature data on the external tank, solid rocket boosters, space shuttle orbiter, main engines and launch pad structures. The scanner can also spot leaks of the cryogenic propellants, and due to its ability to detect distinct temperature differences, can spot any dangerous hydrogen fuel that is burning. The team member also is responsible for photo documentation.

The team wears the highly visible day-glow orange coveralls that are anti-static and flame resistant. Each member also has a self-contained emergency breathing unit that holds about 10 minutes of air.

1050 GMT (6:50 a.m. EDT)

None of the weather rules are being violated right now. There's some clouds around the area, but the skies over Kennedy Space Center are star-filled at the moment.

1030 GMT (6:30 a.m. EDT)

Launch of space shuttle Discovery remains on schedule for 11:38 a.m. EDT today. Filling of the external tank was successfully completed at 5:12 a.m. this morning. The countdown is progressing smoothly with no significant issues under discussion by the launch team.

0625 GMT (2:25 a.m. EDT)

FUELING UNDERWAY. The filling of space shuttle Discovery's external fuel tank with a half-million gallons of supercold propellants has begun at pad 39A for this morning's launch.

The tanking operation commenced with the chilldown thermal conditioning process at 2:13 a.m. EDT. This three-hour process continues by the slow-fill mode and then the fast-fill mode.

The cryogenics are pumped from storage spheres at the pad, through feed lines to the mobile launcher platform, into Discovery's aft compartment and finally into the external fuel tank.

There are two tanks inside the shuttle's external fuel tank. The liquid oxygen tank occupies the top third of the bullet-shaped tank. It will be filled with 143,000 gallons of liquid oxygen chilled to minus 298 degrees Fahrenheit. The liquid hydrogen tank is contained in the bottom two-thirds of the external tank. It holds 385,000 gallons of liquid hydrogen chilled to minus 423 degrees Fahrenheit.

There are no technical issues being worked in the countdown and the weather outlook continues to predict a 40 percent chance of acceptable conditions at this morning's 11:38 a.m. EDT launch time.

MONDAY, OCTOBER 22, 2007

Space shuttle Discovery is getting closer and closer to liftoff on the daunting mission to deliver the space station's Harmony connecting module and move the massive Port 6 solar array power truss.

"Our systems are all good, we're in great shape and there are no issues we're tracking," said NASA Test Director Steve Payne told reporters this morning.

The gantry-like rotating service structure was pulled back to reveal Discovery shortly after 3 p.m. this afternoon, kicking off several hours of work to secure the pad for Tuesday's launch.

Other activities tonight will include configuring all of the switches in the cockpit, activating the shuttle's three power-producing fuel cells and clearing the blast danger area of non-essential personnel.

At 12:13 a.m., the countdown will be going into the two-hour planned hold at the T-minus 6 hour mark. The management team will be meeting to review the progress of the countdown, look at the weather and give the official "go" to begin fueling. The three-hour fueling process should begin around 2:13 a.m. when the count resumes.

The seven astronauts head to bed at 4:30 p.m. They will be awakened for launch day at 1:30 a.m., have breakfast at 2 a.m., pose for the traditional pre-flight photo at 6 a.m., begin suiting up at 7:18 a.m., depart their quarters for the pad at 7:48 a.m. and begin boarding Discovery at 8:18 a.m.

Weather forecasters are predicting a 40 percent chance that conditions will be acceptable for an on-time liftoff at 11:38 a.m. The possibility of clouds and isolated showers in the Kennedy Space Center area are the main concerns.

"We are concerned about the weather tomorrow for launch, mainly due to the fact that the launch time is right around the time our sea breeze will start developing," shuttle weather officer Kathy Winters said. "We're in a southeasterly flow pattern so usually what happens is the sea breeze develops and then pushes inland. The time of the launch is the same time that sea breeze will be forming and so with that, and the moisture in the atmosphere, we're expecting some cumulus cloud development. Also, we should see some coastal showers in the area and we also could have concern for (a low cloud) ceiling in the area right around that time. So with that, we do have a 60 percent chance of KSC weather prohibiting launch."

The outlook improves to 60 percent "go" on Wednesday and Thursday, but forecasters are predicting out-of-limits winds and rain showers at all three of NASA's emergency runways in Spain and France both days where at least one site must be acceptable for the launch to proceed.

SUNDAY, OCTOBER 21, 2007

Nine years after the United States and Russia began building the international space station, NASA is poised for what many agency insiders consider the most difficult assembly mission attempted to date, one that will test the limits of orbital construction.

Read our full story.

SATURDAY, OCTOBER 20, 2007

NASA's shuttle launch team has started Discovery's countdown for a launch attempt Tuesday on what many consider the most challenging space station assembly mission yet attempted. Forecasters are predicting a 60 percent chance of good weather.

Read our full story.

FRIDAY, OCTOBER 19, 2007

Discovery's crew arrived at Kennedy Space Center on Friday afternoon for Tuesday's planned launch. Commander Pam Melroy, speaking at the runway, said the crew agreed with the decision to press ahead with launch despite a recommendation from an independent engineering group to replace three wing leading edge panels.

Read our full story.