BY SPACEFLIGHT NOW

Follow the STS-104 flight of space shuttle Atlantis to deliver the Joint Airlock to the international space station as well as progress of the Expedition Two crew's stay aboard the outpost. Reload this page for the very latest.

MONDAY, JULY 23, 2001
0245 GMT (10:45 p.m. EDT)

NASA's Johnson Space Center issued the following Mission Status Report at 2300 GMT (7 p.m. EDT):

Atlantis crewmembers, Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly, will spend their day preparing the spacecraft for its return to Earth Monday night.

Lindsey and Hobaugh will do a test firing of the reaction control system jets that will be used to maneuver Atlantis as it begins to re-enter the Earth's atmosphere. The pair also will check out the orbiter's flight control surfaces that will be used to maneuver Atlantis when it reaches the lower portions of the atmosphere. Finally, they will test Atlantis' communications systems.

Kavandi, Gernhardt and Reilly will put away some of the equipment they used during their eight days docked to the International Space Station. They also will stow some of the 2,550 pounds of equipment they are bringing home from the station. Atlantis is almost 100 statute miles ahead of the space station and increasing the separation by almost nine miles per 90-minute orbit.

Atlantis is scheduled to land at Kennedy Space Center in Florida on Monday at 11:37 p.m. CDT. Another landing opportunity is available on the subsequent orbit, which would see Atlantis touch down at 1:13 a.m. Tuesday. Though the outlook was improving, forecasts for landing time still carried the possibility of clouds and rain.

During the afternoon, Russian flight controllers performed the first two firings of thrusters of the Progress resupply vehicle docked at the rear of the station's Service Module. These burns and three subsequent firings of the Progress thrusters this week will adjust the inclination of the station's orbit. The slight adjustment is being made to prepare for arrival of Discovery on the STS-105 mission and the next Progress, both in August, and the launch of the Russian Docking Compartment in September.

The Atlantis crew was awakened at 4:36 p.m. Sunday by the song "Orinoco Flow" sung by Enya. The song was played for Mike Gernhardt.

All systems aboard Atlantis continue to function normally as the spacecraft orbits the Earth at an average altitude of 240 statute miles.

SUNDAY, JULY 22, 2001
0616 GMT (2:16 a.m. EDT)

The final separation maneuver by Atlantis has been performed and the shuttle is now quickly departing the vicinity of the international space station at a rate of about eight nautical miles per orbit.

The shuttle crew will enjoy some off duty time to relax later today before going to bed at 8:34 a.m. EDT. They will awakened at 4:34 p.m. to begin packing up the crew cabin and checking out Atlantis' flight control aerosurfaces, hydraulics and steering jets in preparation for reentry and landing back at the Kennedy Space Center in Florida. Touchdown is scheduled for Monday night/Tuesday morning at 12:34 a.m. EDT.

0614 GMT (2:14 a.m. EDT)

Atlantis is now above the station. Pilot Charlie Hobaugh will soon fire the shuttle's jets to leave the vicinity of the station.

0604 GMT (2:04 a.m. EDT)

Shuttle Atlantis is now at a point directly in front the station in terms of the direction of travel. This is known as the +V bar.

0552 GMT (1:52 a.m. EDT)

The shuttle is now reaching a point directly beneath the international space station, passing the so-called +R bar. There is half-a-lap to go in this flyaround.

0543 GMT (1:43 a.m. EDT)

Atlantis is now reaching a point directly behind the station in terms of the direction of travel of the two spacecraft around the Earth. This is known as the -V bar. The separation distance is about 450 feet.

0538 GMT (1:38 a.m. EDT)

Subscribers of our Mission Theater can watch a movie of today's undocking. We also have a clip of the astronauts' farewell ceremony between the shuttle and station crews.

If you aren't a subscriber yet, here is how you can sign up! And click here for a complete listing of all the videos currently available to watch.

0529 GMT (1:29 a.m. EDT)

Atlantis is reaching a point directly above the international space station.

In a pre-flight interview commander Steve Lindsey explained why the shuttle performs this flyaround maneuver:

"There's a couple of reasons why we want to do a flyaround around the station...we do a lot of photo-documentation of it each time we build to note the changes to the station; engineers and scientists can get a lot of information on how the station is doing just by doing the pictures as we fly around.

"On our flight we're also carrying a IMAX 3-D camera out in the payload bay -- several flights have been carrying it -- and we're doing it for, eventually they're going to do a movie on space station assembly, so we'll be doing a lot of documentation with that camera as well.

"The other thing it provides for Charlie in particular, is a chance for a Pilot to fly the vehicle. And which is why I would like him to do that. So he gets a chance to feel what the vehicle flies like. For myself, I've never had an opportunity to fly the vehicle on my previous two flights...But by giving him this opportunity, eventually he'll probably be sitting in my shoes as a Commander someday -- it gives him experience and confidence in flying the vehicle as well."

0520 GMT (1:20 a.m. EDT)

Under the control of pilot Charlie Hobaugh, Atlantis is now beginning the lap-and-a quarter flyaround of the international space station. The flyaround starts with the shuttle in front of the station, takes Atlantis to a point directly above the complex, then behind and below the outpost, back out in front and finally above where the final separation engine firing will be performed.

0517 GMT (1:17 a.m. EDT)

Distance now just over 350 feet.

0456 GMT (12:56 a.m. EDT)

Now 20 feet. Separation rate nearly two-tenths of a foot per second. Also, the station has resumed its own attitude control.

0455 GMT (12:55 a.m. EDT)

Distance now 10 feet as the two two spacecraft separate 240 miles above the North Atlantic Ocean. Pilot Charlie Hobaugh is at the controls of Atlantis.

0454 GMT (12:54 a.m. EDT)

UNDOCKING! Atlantis is slowing backing away from the international space station after an eight-day stay at the outpost. The shuttle delivered and inaugurated the Joint Airlock Quest -- the station's new doorway for spacewalking astronauts.

0452 GMT (12:52 a.m. EDT)

Two minutes until undocking. The command has been issued to begin driving open the hooks holding Atlantis and station together. Once the hooks and latches are opened, one final command will be sent to undock the shuttle.

0450 GMT (12:50 a.m. EDT)

Now four minutes from the planned undocking time. The steering jets on Atlantis are inhibited for the period of physical undocking from the station. The separation occurs when large springs push the two craft apart.

0446 GMT (12:46 a.m. EDT)

The space shuttle flight control team has been polled and all systems are "go" for undocking.

0439 GMT (12:39 a.m. EDT)

Now about 15 minutes from Atlantis' undocking from the international space station.

0429 GMT (12:29 a.m. EDT)

Atlantis' docking mechanism is now powered up. And the international space station's solar arrays -- the U.S. P6 wings and arrays on the Russian modules -- are being turned to an edge-on position relative to Atlantis. The repositioning is done to ensure the jet thruster plumes from the shuttle during departure don't damage the delicate arrays.

0424 GMT (12:24 a.m. EDT)

Now 30 minutes from undocking. At the time of separation the shuttle and station will be flying about 240 miles above the Northern Atlantic, just east of North America.

0408 GMT (12:08 a.m. EDT)

The vestibule between the docking ports of Atlantis and station has been depressurized and successfully leak checked.

In a pre-flight interview commander Steve Lindsey gave a description of the activities upcoming for today's undocking:

"Well, once we close hatches for the final time what we're going to do is prepare to undock. And in this case, the roles are reversed: my Pilot, Charlie Hobaugh, will be flying in the aft station, he'll be doing the manual flying, and I'll essentially be doing his role in the front, which is monitoring the vehicle systems and kind of coaching him, just like he coached me on the rendezvous and docking phase. So Janet and Mike Gernhardt are our primary docking system operators, they'll be actually doing the physical undocking from the station; once we're separate then Charlie's going to back the vehicle back to about 450 feet or so away from the station, and he's going to start a flyaround and just do a big circle around the space station -- probably one or two laps, depending on how much propellant we have -- and then when he's done with that then he'll do a couple of separation burns and we'll separate away from the station. So it's his first opportunity to fly the vehicle."

0401 GMT (12:01 a.m. EDT)

Space shuttle Atlantis has now assumed control of the station's attitude in preparation for the undocking at 12:54 a.m. EDT. The station's control system has been inhibited.

0254 GMT (10:54 p.m. EDT Sat.)

The hatchway between space shuttle Atlantis and the international space station has been closed in preparation for tonight's undocking, which is about two hours away.

SATURDAY, JULY 21, 2001
2200 GMT (6:00 p.m. EDT)

The astronauts of space shuttle Atlantis have been awakened for Flight Day 11 of this STS-104 mission. The crew will bid farewell to the international space station residents over the next couple of hours before closing the hatches between the two spacecraft at 9:59 p.m. EDT. Atlantis is scheduled to undock from the station at 12:54 a.m. EDT after an eight-day visit that saw the delivery of the Joint Airlock Quest and four high-pressure gas tanks.

1100 GMT (07:00 a.m. EDT)

Astronauts Michael Gernhardt and James Reilly staged a third and final spacewalk today, the first to use the international space station's new $164 million airlock module. Other than taking longer to vent down to vacuum than expected, the new portal worked flawlessly, opening a new era for the international outpost. Read the full story.

0837 GMT (4:37 a.m. EDT)

EVA ENDS. The international space station's Joint Airlock Quest is now being repressurized, officially bringing today's spacewalk by Mike Gernhardt and Jim Reilly to a conclusion at 4:37 a.m. EDT. The successful EVA lasted four hours and two minutes.

0832 GMT (4:32 a.m. EDT)

The spacewalkers are back inside the Quest airlock with the hatchway closed. This EVA will officially conclude when repressurization begins.

0749 GMT (3:49 a.m. EDT)

Checks of the solar array wing bearing didn't reveal anything that would explain the binding sometimes experienced when the structure moves to track the sun. And with that all the activities of today's spacewalk are completed. The spacewalkers are now headed back to the airlock.

0738 GMT (3:38 a.m. EDT)

Reilly reports none of the status indicator lights on the Floating Potential Probe are lit.

0735 GMT (3:35 a.m. EDT)

Now three hours into today's spacewalk. Gernhardt and Reilly are currently climbing up the P6 solar array truss of the international space station to inspect a suspect drive motor on one of the solar wings and the Floating Potential Probe device, which hasn't functioned properly since it was deployed.

0708 GMT (3:08 a.m. EDT)

The spacewalkers are working on some other chores including stowing a cable on the Destiny module no longer needed and installing thermal covers on bolts of the robotic arm.

0648 GMT (2:48 a.m. EDT)

The nitrogen tank checkout has been completed successfully, confirming the tank was connected properly.

0608 GMT (2:08 a.m. EDT)

The second high-pressure nitrogen tank has been mounted to the hull of the Joint Airlock Quest. The airlock now has all four of its gas tanks attached.

0607 GMT (2:07 a.m. EDT)

The station's robot arm has ungrappled the nitrogen tank. The two spacewalkers are now manually moving the dog house-shaped structure in their hands for attachment to the airlock.

Over the past hour the spacewalkers completed work to install thermal covers over the grapple fixtures on the other high-pressure gas tanks.

0500 GMT (1:00 a.m. EDT)

The station's robot arm is now lifting the 1,200-pound nitrogen gas tank from the Spacelab pallet in Atlantis' payload bay, beginning the approximate one-hour process of manuevering the tank into position for mounting to the Joint Airlock.

Meanwhile, spacewalker Jim Reilly is hooking up a cable to Quest that will route communications when spacewalks featuring Russian Orlan spacesuits are staged from the airlock in the future.

0450 GMT (12:50 a.m. EDT)

Now outside the airlock, spacewalker Mike Gernhardt is making his way into Atlantis' payload bay to release latches holding the nitrogen gas tank. This will free the station's arm to move the tank.

0438 GMT (12:38 a.m. EDT)

EVA BEGINS. Astronauts Mike Gernhardt and Jim Reilly switched their spacesuits to internal battery power at 12:35 a.m. EDT, signalling the official start of today's historic first spacewalk from the international space station's new Joint Airlock Quest.

The EVA is the 108th in U.S. space program history, 24th dedicated to international space station construction and third of three planned during Atlantis' current mission. This is Gernhardt's fourth EVA and Reilly's third.

0434 GMT (12:34 a.m. EDT)

With only a half-pound of pressure per square inch left in the Quest airlock, the "go" has been given to open the outer hatch to space.

0424 GMT (12:24 a.m. EDT)

Mission Control has checked over the data to ensure there isn't any mis-configuration that would allow air to leak into the airlock as it is being depressurized. No problems were noted. The depressurization continues with the pressure less than 1 psi.

0414 GMT (12:14 a.m. EDT)

The airlock depressurization is nearing completion. This is taking a bit longer than expected. But there are no problems reported.

0405 GMT (12:05 a.m. EDT)

The nitrogen gas tank has been grappled by the station's robotic arm. The tank will be attached to the Joint Airlock during tonight's spacewalk.

0353 GMT (11:53 p.m. EDT, Fri.)

Canadarm2 is now moving into position to grapple the remaining high-pressure gas tank riding in Atlantis payload bay. The arm will move the tank to a point near the Joint Airlock where the spacewalkers will take it in their hands and manually dock it to Quest's hull.

0331 GMT (11:31 p.m. EDT, Fri.)

The space station's robot arm is in motion with Jim Voss at the controls in the Destiny module.

0328 GMT (11:28 p.m. EDT, Fri.)

Hobaugh is starting the 30-minute-long depressurization process.

0321 GMT (11:21 p.m. EDT, Fri.)

The Houston space station mission control, which is overseeing its first spacewalk, has given a "go" to begin depressurization of the airlock. Meanwhile, Janet Kavandi is activating the shuttle's robot arm and Susan Helms has asked for permission to prepare the station's arm.

0320 GMT (11:20 p.m. EDT, Fri.)

Hobaugh has now closed the hatch between the airlock's equipment lock and crew lock compartments. Depressurization will begin shortly and should take about half an hour to complete.

0315 GMT (11:15 p.m. EDT, Fri.)

The two spacewalkers have floated through the hatch into the crew lock portion of the airlock.

0255 GMT (10:55 p.m. EDT, Fri.)

With Gernhardt and Reilly safely sealed in their suits, the hatch between the Quest airlock the rest of the space station has been opened and we have seen our first television views of the suited astronauts inside the airlock.

0220 GMT (10:20 p.m. EDT, Fri.)

Atlantis pilot Charlie Hobaugh, who has been assisting the spacewalkers get into their suits inside the airlock, is repressurising the airlock to 14.7 psi. This will allow Hobaugh to reopen the hatch between the airlock and the Unity module. Once Gernhardt and Reilly complete their pre-breathe inside the suit they will move into the crew lock portion of the airlock.

0216 GMT (10:16 p.m. EDT, Fri.)

The spacesuits are being purged before the astronauts resume their pre-breathe of pure oxygen. Depressurization of the airlock is expected to start about an hour and 10 minutes from now. The spacewalk is now expected to start a little before 0400 GMT (midnight EDT) as preparations are running slightly ahead of schedule.

0205 GMT (10:05 p.m. EDT, Fri.)

The two spacewalkers have donned their spacesuit helmets and activated the suit fans. They will shortly climb into the crew lock portion of the airlock.

0122 GMT (9:22 p.m. EDT, Fri.)

The pre-breathe period is now complete. Gernhardt and Reilly, assisted by shuttle pilot Charlie Hobaugh, will now start to put on their spacewalking gear.

0041 GMT (8:41 p.m. EDT, Fri.)

Shuttle skipper Steve Lindsey reports the airlock's depressurization pump is not making the "painfully loud" noise encountered by the crew during tests earlier this week. A faulty hose appears to be to blame for the noise.

0035 GMT (8:35 p.m. EDT, Fri.)

Gernhardt and Reilly, along with shuttle crewmate Charlie Hobaugh are sealed in the Quest airlock which is now being depressurised to 10.2 psi, part of the continuing process to ensure the spacewalkers do not suffer the bends. Hobaugh will help assist the spacewalkers into their suits before they enter the crew lock from where they will begin their EVA.

0015 GMT (8:15 p.m. EDT, Fri.)

Jim Reilly has completed a short but intense workout on the station's exercise bike, part of a new protocol to remove nitrogen from astronauts' blood prior to a spacewalk and avoid the condition known as the "bends". Gernhardt will now take his turn on the bike.

Mission Theater subscribers can see a video feature about the station's new airlock. Non-subscribers can sign-up here.

FRIDAY, JULY 20, 2001
2355 GMT (7:55 p.m. EDT)

Astronauts Mike Gernhardt and Jim Reilly began a two-hour pre-breathe of pure oxygen at 2345 GMT (7:45 p.m. EDT) to rid their blood of nitrogen in preparation for tonight's spacewalk.

2200 GMT (6:00 p.m. EDT)

The crew of Atlantis were awakened at 2104 GMT (5:04 p.m. EDT) to begin flight day ten of their mission, a day that will feature the inaugural spacewalk from the space station's newly installed Quest airlock.

Preparations for that spacewalk are expected to start at about 2304 GMT (7:04 p.m. EDT) this evening. The hatch on the Quest airlock is due to swing open into the void of space for the first time at 0409 GMT (12:09 a.m. EDT).

During tonight's planned 4 hour 25 minute excursion the astronauts will mount the fourth and final high pressure gas tank to the hull of the airlock, check a joint on one of the station's large U.S. solar arrays, and inspect the name plate of the Unity node, which appears to be cracking.

0430 GMT (12:30 a.m. EDT)

NASA has proclaimed the newly installed Quest airlock ready to support Friday night's planned 4 1/2-hour spacewalk by astronauts Mike Gernhardt and Jim Reilly. The two men rehearsed spacewalk preparations in the airlock over the past couple of hours.

"We've been training and planning for this for four years and we're really looking forward to that," Gernhardt told reporters during a news conference. "We're really happy things have gone well the last couple of days and we have the airlock in a posture that will support that EVA. We're going to spend the rest of the day doing some final touches and then try to get a good night's sleep.

"It will be very exciting as we open the hatch and come out. As you know, the hatch is facing Earth so it'll be like stepping off into the big void, dropping down toward Earth, so we're looking forward to that. We've got one more tank to put on to complete the mission objectives and some little clean up tasks so it should be a nice nominal EVA and we're really looking forward to it."

0005 GMT (8:05 p.m. EDT Thurs.)

Here is the latest NASA status report:

The eight Atlantis and International Space Station crewmembers will start their day with a dry run of a spacewalk from the station's new Quest airlock, completing their testing and activation of the airlock. Atlantis spacewalkers Mike Gernhardt and Jim Reilly, assisted by Pilot Charlie Hobaugh and Expedition Two Flight Engineer Jim Voss, will simulate spacewalk preparations beginning around 8 p.m.

Atlantis Commander Steve Lindsey and Mission Specialist Janet Kavandi will assist with the final checks of the airlock later in the morning. Subsequently, all eight crewmembers will gather to review the procedures for Friday's spacewalk, the third of the mission. During that spacewalk, Gernhardt and Reilly will attach the final nitrogen gas tank to the airlock, assisted by Voss and Expedition Two Flight Engineer Susan Helms who will be operating the station's robotic arm. At 11:11 p.m., the two crews will participate in a joint news conference with media representatives at several NASA centers and the Russian Mission Control Center in Korolev. That conference will run for 26 minutes and will be shown live on NASA TV. In addition, Lindsey is scheduled to downlink a tour of the Quest airlock around 4 a.m.

Station Commander Yury Usachev will perform various periodic maintenance duties on the station's Russian systems, as well as help fellow crewmates Voss and Helms prepare for robotics operations related to Friday evening's spacewalk.

The Atlantis crew was awakened at 5:04 p.m. by the song "A Time To Dance" by Janet Giroux played by the Space Center Intermediate School Symphonic Band. The band was directed by Giroux and the song was played for Reilly.

THURSDAY, JULY 19, 2001
1430 GMT (10:30 a.m. EDT)

After fixing one leak, the station crew has encountered others. This time between the airlock's equipment and crew locks. The leaks were discovered after a hatch had been installed between the two compartments of the Quest airlock and the pressure inside the crew lock portion was lowered to 5 psi.

The leakage of about 0.37 psi per hour is thought to originate from pressure equalization valve and a depressurization pump line fitting. Station astronaut Jim Voss used an ultra-sonic leak detector to help pinpoint the location.

Flight controllers believe the leaks, which are considered minor, can be plugged or worked around without any impact to the first spacewalk from the station planned for tomorrow night.

"At this point is doesn't appear to be an issue," said NASA mission commentator Kyle Herring.

0330 GMT (11:30 p.m. EDT Wed.)

Astronauts aboard the international space station successfully swapped out a leaky inter-module ventilation valve tonight, taking an unused valve from the Destiny module to replace the troublesome valve between the Unity node and newly installed Joint Airlock Quest. This leaky valve was part of the reason work fell behind schedule to outfit the airlock this week, forcing NASA officials to extend Atlantis' mission by one day.

Other activities underway tonight will include continued work to move equipment into Quest in support of Friday night's spacewalk from the new airlock. And the hatch designed to separate the two chambers of the airlock module will be installed.

WEDNESDAY, JULY 18, 2001

After a computer scare reminiscent of problems that crippled the international space station in April, two spacewalkers successfully attached three high-pressure gas tanks to the lab's new airlock today, manually wrestling the 1,200-pound canisters into place. Read our full story of the spacewalk.

0933 GMT (5:33 a.m. EDT)

EVA ENDS. Space shuttle Atlantis' airlock is now being repressurized, officially bringing today's spacewalk by Mike Gernhardt and Jim Reilly to a conclusion at 5:33 a.m. EDT. The EVA lasted six hours and 29 minutes, an hour longer than expected because the astronauts transferred three of the high-pressure gas tanks from the shuttle to the Joint Airlock instead of the two that were scheduled, basically allowing the spacewalkers to get ahead with the remaining tasks left to be performed during the EVA on Friday night.

It was the 107th spacewalk by astronauts on U.S. space missions, the 66th in shuttle program history, the 23rd dedicated to space station assembly and the second of three planned during Atlantis' current flight.

0912 GMT (5:12 a.m. EDT)

The oxygen tank checkout has been completed successfully, confirming the tank was connected properly. The spacewalkers are now making their way back to Atlantis' payload bay to stow their equipment and tools before climbing back into the shuttle airlock.

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

The second high-pressure oxygen tank has been mounted to the hull of the Joint Airlock Quest. Spacewalker Gernhardt will now mate a quick-disconnect line from the tank to the airlock. And then the spacewalkers will clean up and head back into Atlantis' airlock to wrap up today's EVA.

0844 GMT (4:44 a.m. EDT)

The station's robot arm has ungrappled the second oxygen tank. The two spacewalkers are now manually moving the dog house-shaped structure in their hands for attachment to the airlock.

0834 GMT (4:34 a.m. EDT)

Now five-and-a-half hours into today's spacewalk. The second oxygen tank is nearly in place for release from the robot arm and into the hands of the spacewalkers.

0752 GMT (3:52 a.m. EDT)

The second high-pressure oxygen gas tank has been grappled by the station's robotic arm. The tank will be lifted off the Spacelab pallet it has been riding on in Atlantis' payload bay and moved to its new home on the exterior of the Joint Airlock Quest over the course of the next hour or so.

Today's spacewalk was originally slated to last around 5 1/2 hours, but that duration has been extended by about an hour with the decision to move this second oxygen tank as a get-ahead task. The tank was supposed to be moved during the mission's third spacewalk on Friday night.

0731 GMT (3:31 a.m. EDT)

Canadarm2 is now making its way to grapple the second oxygen tank riding in Atlantis' payload bay for transfer to the airlock today.

0714 GMT (3:14 a.m. EDT)

Good pressures are reported from the nitrogen tank to Quest, confirming a successful hookup. With one oxygen and one nitrogen tank, the stage is now set for Quest's maiden use on Friday night when Gernhardt and Reilly conduct the third spacewalk of Atlantis' mission from the station's new airlock.

0710 GMT (3:10 a.m. EDT)

The spacewalkers report success in getting the quick-disconnect attached between the nitrogen tank and airlock.

0704 GMT (3:04 a.m. EDT)

Now four hours into today's spacewalk.

0654 GMT (2:54 a.m. EDT)

The spacewalkers are struggling a bit with mating the quick-disconnect fitting between the airlock and the newly installed nitrogen tank. They are waiting for orbital sunrise to warm up the line before trying again to connect it.

0642 GMT (2:42 a.m. EDT)

With the spacewalk going well, officials have decided to install a third tank today. Plans had called for two tanks to be mounted to the airlock today and the other two tanks during spacewalk No. 3, which is scheduled for Friday night. But it was decided to get ahead and transfer the second oxygen tank now. The Canadarm2 will be heading back to the payload bay to pick up the tank.

0639 GMT (2:39 a.m. EDT)

The first nitrogen tank has been attached to the Joint Airlock Quest, giving the station's newest module two of its four high-pressure gas tanks.

0637 GMT (2:37 a.m. EDT)

The station's robot arm has ungrappled the nitrogen tank, leaving the dog house-sized structure in the hands of the two spacewalkers to manually mount it to the airlock.

0624 GMT (2:24 a.m. EDT)

Mission Control reports the oxygen tank mounted to the airlock earlier during this spacewalk is functioning normally. Oxygen is flowing into the airlock as planned, valves are working properly and leak checks have been successfully passed.

0619 GMT (2:19 a.m. EDT)

Canadarm2 is performing a roll maneuver to get the nitrogen tank in the right position for spacewalkers Jim Reilly and Mike Gernhardt to manually grab the 1,200-lb structure and dock it to the airlock.

0555 GMT (1:55 a.m. EDT)

Helms has reconfigured one of the quick-disconnects on the interior of the airlock Quest, successfully resolving the flow problem from the high-pressure oxygen gas tank. There were some mis-labeled valves inside the station, which caused the mix up.

0552 GMT (1:52 a.m. EDT)

Susan Helms has handed the Canadarm2 controls to Jim Voss, who is now flying the arm with the nitrogen tank.

0540 GMT (1:40 a.m. EDT)

Controlling the station's robot arm from inside the Destiny lab, the Expedition Two crew is now slowing lifting the nitrogen tank off the Spacelab pallet in the shuttle's payload bay.

Meanwhile, the astronauts are checking the configuration of lines inside the station that could be causing the lack of oxygen flow from the newly installed oxygen tank.

0530 GMT (1:30 a.m. EDT)

The station robotic arm has grappled the high-pressure nitrogen gas tank riding in Atlantis' payload bay in preparation for transporting the dog house-sized unit for mating to the airlock Quest.

0504 GMT (1:04 a.m. EDT)

We are now two hours into the spacewalk.

0500 GMT (1:00 a.m. EDT)

Mission control has asked Reilly to check all the latches are closed on the newly installed oxygen tank. One appeared to be in the "ready" position in television images from orbit.

0455 GMT (12:55 a.m. EDT)

The Canadarm2 is back in motion, returning to the payload bay to collect high pressure tank No. 4, the first nitrogen tank.

Meanwhile, the environmental systems officer in the station flight control room believes a mis-configured quick-disconnect could be responsible for the lack of oxygen flow to the airlock from the newly installed tank 1.

0448 GMT (12:48 a.m. EDT)

Reilly has closed the isolation valve on the oxygen tank while flight controllers try to determine why they are not seeing the expected pressure rise in the airlock's oxygen system.

0444 GMT (12:44 a.m. EDT)

Mission control has instructed the crews to proceed with the installation of the second tank, this time containing nitrogen. The station arm will move back into the payload bay to pick up tank No.4 and Gernhardt will make his way back to the bay to assist in the unlatching of the tank.

0441 GMT (12:41 a.m. EDT)

Mission control reports it is still not seeing an expected pressure increase in the airlock oxygen lines when the spacewalkers open an isolation valve on the newly installed tank.

0438 GMT (12:38 a.m. EDT)

Jim Reilly has reopened an isolation valve on the oxygen tank. Gernhardt had opened the valve earlier but flight controllers did not see the expected pressure rise in the airlock lines.

0430 GMT (12:30 a.m. EDT)

Checks are underway to ensure the oxygen tank is correctly seated on the connectors to the airlock.

0421 GMT (12:21 a.m. EDT)

Oxygen tank No.1 is "soft-docked" to the hull of the airlock.

0420 GMT (12:20 a.m. EDT)

The robot arm has backed away from the tank and the spacewalkers are lowering the tank.

0418 GMT (12:18 a.m. EDT)

Canadarm2 has released oxygen tank No.1, leaving it in the hands of spacewalkers Gernhardt and Reilly. They will now manually lower the tank into position on the hull of the airlock.

0416 GMT (12:16 a.m. EDT)

The spacewalkers have the tank in their hands and they have given the station crew a "go" to release the robot arm's grip on the housing.

0350 GMT (11:50 p.m. EDT)

Helms is carefully inching the dog house-shaped oxygen tank towards the airlock, putting it within reach of the two spacewalkers who will manually lower the housing into place on the metallic hull of the airlock.

0340 GMT (11:40 p.m. EDT)

Gernhardt and Reilly are on the hull of the airlock setting up their tools, as the oxygen tank rises towards them on the station arm.

0327 GMT (11:27 p.m. EDT)

The 56-ft-long Canadarm2 had begun lifting the first high pressure gas tank from the shuttle's payload bay.

0319 GMT (11:19 p.m. EDT)

The spacewalkers are preparing to release oxygen tank No.1 from its craddle in the payload bay. The station arm now has a firm grip on the 1,200 lb housing.

0313 GMT (11:13 p.m. EDT)

Canadarm2 is moving in to grapple oxygen tank No.1.

0310 GMT (11:10 p.m. EDT)

Mike Gernhardt has emerged from the airlock hatch.

This EVA is the 107th in U.S. space program history, the 66th to occur from the space shuttle, 23rd dedicated to international space station construction and second of third of Atlantis' current mission. This is Gernhardt's third EVA and Reilly's second.

0305 GMT (11:05 p.m. EDT)

The official start of today's spacewalk was 0304 GMT (11:04 p.m. EDT), when the astronauts switched their space suits to internal battery power.

The space station crew has been given a "go" to grapple the first high pressure gas tank, oxygen tank number 1.

0303 GMT (11:03 p.m. EDT)

Atlantis' airlock has been fully depressurized and is at a vacuum. The spacewalkers have been given a "go" to open the hatch.

0252 GMT (10:52 p.m. EDT)

Atlantis' airlock is being depressurized. Once the 15-minute-long operation is complete, Gernhardt and Reilly will perform last-minute suit checks before switching to their suit battery power and stepping outside.

0217 GMT (10:17 p.m. EDT)

The space station's robot arm is moving into position to grapple the first of the high pressure gas tanks.

0102 GMT (9:02 p.m. EDT)

A reset of the Command and Control computer No.3 hard disk appears to have solved the problem, clearing the way for the use of the station's robot arm as planned during tonight's spacewalk.

0100 GMT (9:00 p.m. EDT)

As flight controllers continue to weigh their options following tonight's computer failure, spacewalk preparations have resumed with Mike Gernhardt about to climb into his spacesuit.

Meanwhile engineers with Honeywell, responsible for the failed computer hard disk, have determined the disk is spinning but its software may have crashed. Susan Helms has been instructed to reset the disk in the hope of restoring operation of the computer.

Currently tonight's spacewalk is not likely to get underway before 10:45 p.m. EDT.

0038 GMT (8:38 p.m. EDT)

Here's what we know so far about the computer failure aboard the space station:

Command and Control (C&C) computer No.3, the station's primary computer, suffered a hard disk failure at around 6:45 p.m. EDT as engineers were performing a data dump on one of the backup computers, C&C No.1. Mission control is now attempting to reset a card in the computer in the hope of restoring it.

Without the primary computer Susan Helms cannot activate and operate the station's robot arm and flight controllers on the ground cannot monitor its health. The arm was to be used during tonight's spacewalk to hand off two high pressure gas tanks to the spacewalkers for installation on the hull of the airlock.

If the primary computer cannot be reactivated, the station crew could switch to the back up computer, C&C No.1, which is also loaded with the robotics software.

In a worst case, the shuttle arm could be used to lift another, but identical set of gas tanks. However, flight controllers are evaluating whether the current position of the station arm would get in the way.

For the time being flight controllers have told the Atlantis crew to put spacewalk preparations on hold while they study the problem. They also instructed the crew to review the back-up proceedures for using the shuttle's arm.

"The space station flight control team is currently working to analyze the data as to what exactly tripped off command and control computer number 3," mission commentator Rob Navias said. "The expectation is that the mass storage device will be restored and command and control computer number 3 will be brought back on line before the end of spacewalking preparations."

0005 GMT (8:05 p.m. EDT)

Mission control has told the shuttle crew to hold off spacewalk preparations as engineers continue to evaluate the failure of the hard disk used by the station's primary command and control computer.

The computer is needed to operate the station's robot arm, which plays a crucial role in tonight's spacewalk.

Flight controllers are considering switching to a back up station computer. If that doesn't work the shuttle arm could be used in a worst case.

The Atlantis crew are already reviewing proceedures for using the shuttle's arm if necessary.

0005 GMT (8:05 p.m. EDT)

Mission control has told the shuttle crew to hold off spacewalk preparations as engineers continue to evaluate the failure of hard disk in the station's primary command and control computer.

0005 GMT (8:05 p.m. EDT)

Mission control has told the shuttle crew to hold off spacewalk preparations as engineers continue to evaluate the failure of hard disk in the station's primary command and control computer.

The computer is needed to operate the station's robot arm, which plays a crucial role in tonight's spacewalk.

Flight controllers are considering switching to a back up station computer. If that doesn't work the shuttle arm could be used in a worst case.

The Atlantis crew are already reviewing proceedures for using the shuttle's arm if necessary.

TUESDAY, JULY 17, 2001
2327 GMT (7:27 p.m. EDT)

The mass memory device, or hard disk, on the space station's primary computer has suffered a failure. Flight controllers are looking into the problem.

A NASA spokesman said at present the glitch is not expected to impact tonight's planned space walk as two other computers are working normally. The station computer systems are needed for the operation of the station's robot arm, which plays a crucial role in tonight's work to attach high pressure gas tanks to the station's airlock.

During the last shuttle visit to the station, hard disk failures caused the loss of all three station computers and left the complex crippled for several days.

Meanwhile, we have received updated landing times for Atlantis. Following the mission extension, touchdown is now expected at 12:36 a.m. EDT on Tuesday, July 24.

2125 GMT (5:25 p.m. EDT)

The crew of space shuttle Atlantis was awakened at 5:08 p.m. EDT (2108 GMT) with a musical birthday greeting for mission specialist Janet Kavandi who celebrates her 42nd birthday today. The crew was also informed that their mission has been extended a day.

Flight controllers have refined their landing times and now put Atlantis' touchdown at the Kennedy Space Center at 11:46 p.m. ET on July 23.

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

The mission management team has decided to extend the flight of Atlantis by one day to relax the workload for the station and shuttle crews. The third spacewalk of the mission, the first from the station's Quest airlock, will now take place on Friday night.

Landing is now scheduled for Tuesday morning at around 2 a.m. EDT.

0808 GMT (4:08 a.m. EDT)

Lead STS-104 Flight Director Paul Hill says NASA is considering adding an extra day to the Atlantis mission to relax the pace of activities for the astronauts in preparation for the first spacewalk from the new Joint Airlock. The activities are running about a half-day behind schedule due to the cooling loop water leak yesterday and today's leaky ventilation valve that have pushed back the timeline.

No decision has been made, though it could come later this afternoon. Officials need to determine if all airlock outfitting can be finished in time to support Thursday's spacewalk from the new module. If more time is needed to complete the outfitting, then the mission could be extended by a day, delaying the milestone spacewalk to Friday night.

In space right now the spacewalkers are going through a rehearsal of the EVA protocols to practice the procedures that will be used during the maiden excursion from Quest.

0628 GMT (2:28 a.m. EDT)

The station crew has capped the leaky valve, clearing the way for spacewalkers Mike Gernhardt and Jim Reilly to practice procedures in Quest for a spacewalk later in the week from the newly installed airlock.

Troubleshooting efforts to fix the leak have been unsuccessful so far. However, Voss just reported the valve may not be seated properly. In any event, the valve is capped off to temporarily stop the leakage.

0232 GMT (10:32 p.m. EDT)

Station crewmember Jim Voss has informed mission control that the inter-module valve between Unity and Quest is still leaking, despite hours of troubleshooting. Flight controllers are now likely to recommend swapping the leaky valve with another valve in the vestibule.

0059 GMT (8:59 p.m. EDT)

Space station astronaut Susan Helms reports the purge of the oxygen system aboard the Quest airlock has been completed. This task was delayed from yesterday due to troubleshooting of the cooling system. Meanwhile, the Atlantis astronauts are preparing for a test to see how shuttle jet firings affect the station stack, in particular the solar arrays.

0005 GMT (8:05 p.m. EDT)

The crew of Atlantis was awakened at 5:19 p.m. EDT (2119 GMT) to the sound of "Nobody Does it Better" by Carly Simon from the soundtrack of the movie "The Spy Who Loved Me".

Today's flight plan for the shuttle and station crews includes: isolating and plugging an air leak between the Unity module and the Quest airlock; purging the airlock oxygen system; relocating a hatch inside the airlock module; various tasks to activate the airlock; and preparing spacewalk equipment.

MONDAY, JULY 16, 2001
1500 GMT (11:00 a.m. EDT)

A water coolant leak overnight slowed work to activate the space station's newly installed Quest airlock.

About half a litre of water spilled as the astronauts attempted to connect lines between the Unity module and the airlock. A small amount of leakage had been anticipated, but ground controllers believe air in the coolant loop or higher than expected temperatures may have forced the water out.

"We got towels on it right away," shuttle commander Steve Lindsey said in an interview with the Associated Press. "We contained the leak very quickly [and] put the cap back on before too much could come out."

When the lines were eventually connected, the space station's main computer detected a drop in pressure, which it interpreted as a leak, setting off a Klaxon-style alarm in the Destiny module and shutting down the cooling system.

"We anticipated some amount of air in those lines and we had all kinds of calculations to tell us exactly how much air there would be, whether or not the gas traps in the system were capable of taking that air out without hurting the pumps, etc.," said lead flight director Paul Hill.

"What we hadn't accounted for was the software response detecting that pressure drop and shutting the system down because it thought it had a leak. That surprised us."

The resulting troubleshooting has delayed some work to prepare the airlock for use, but controllers said there should be no significant impact. The crew was able to activate the airlock's computer, communications, smoke detector and ventilation systems.

Flight controllers detected an additional problem just before the crews went to bed Monday morning. Telemetry indicated an air leak in the vestibule between Unity and the airlock. Station astronaut Jim Voss was able to confirm the leak.

"Using our highly sensitive instrument -- our ears -- the starboard aft IMV valve seems to be where the leak is," Voss told flight controllers. "We can hear some air flow through there."

Voss closed a vent relief valve that will hold the pressure until the crew wakes up later on Monday and troubleshooting can resume.

"We'll have some words and a plan of action in the morning," station CAPCOM Dan Burbank radioed.

In the other major activity of flight day five, Atlantis' thrusters were fired in an hour-long maneuver to raise the space station's altitude by about 2.3 nautical miles.

SUNDAY, JULY 15, 2001
2300 GMT (7:00 p.m. EDT)

The astronauts are awake for Flight Day 5, which will see outfitting of the Joint Airlock begin in earnest. Also tonight the shuttle's thrusters will be used to reboost the station's altitude by about 3.7 km.

0939 GMT (5:39 a.m. EDT)

Station astronaut Susan Helms, operating the lab's new Canadarm2 space crane with a jeweler's precision, lifted a 6.5-ton airlock module from the shuttle Atlantis' cargo bay today and attached it to the side of the international space station. Read our full story.

0909 GMT (5:09 a.m. EDT)

EVA ENDS. Space shuttle Atlantis' airlock is now being repressurized, officially bringing today's spacewalk by Mike Gernhardt and Jim Reilly to a conclusion at 5:09 a.m. EDT. The EVA lasted five hours and 59 minutes, an hour shorter than expected. The excursion was extremely smooth and trouble-free.

It was the 106th spacewalk by astronauts on U.S. space missions, the 65th in shuttle program history and the 22nd dedicated to space station assembly. In the 22 station spacewalks to date, 24 astronauts and two Russian cosmonauts logged 145 hours and eight minutes putting the outpost together.

Meanwhile, the 16 electrically-driven bolts holding the airlock to the station have been tightened to their full 19,000 pounds of torque. This procedure was expected to occur later today after the docking mechanism seals were allowed to thermally equalize. But Mission Control moved up the activity since the equalization wasn't required.

0858 GMT (4:58 a.m. EDT)

Mission Control has activated the heaters on the Joint Airlock, confirming the power umbilicals connected by spacewalker Gernhardt were properly attached. This allows the spacewalkers, who are already back at Atlantis' airlock, to close up the hatch and begin repressurization to conclude today's EVA.

0837 GMT (4:37 a.m. EDT)

Gernhardt has been installing a couple of handrails to the exterior of Quest. However, he had some difficulty installing one of the fixtures when it didn't fit into the socket properly. So the ground told him to give up for today and try installing a different handrail during the next spacewalk. So the spacewalkers will now begin cleaning up and heading back inside Atlantis having completed all the chores on this highly successful day in space.

0814 GMT (4:14 a.m. EDT)

Canadarm2 has now ungrappled the Quest airlock, which is firmly mounted to the space station. Also, the shuttle's arm is being put away for the day having completed its job. Meanwhile, spacewalker Mike Gernhardt has connected the power cabling between the station and airlock and Jim Reilly is positioning equipment on the station exterior for use in future EVAs.

0740 GMT (3:40 a.m. EDT)

AIRLOCK INSTALLED! With the 16 bolts initially tightened, the Joint Airlock Quest is now firmly connected to the Unity node, officially becoming part of the international space station. The installation completes the initial phase of station assembly. In about 7 hours the bolts will be driven to their full 19,000 pounds of torque after the docking mechanism seals are able to thermally equalize.

0731 GMT (3:31 a.m. EDT)

The $164 million Joint Airlock Quest has been docked to the berthing mechanism on the starboard side of the international space station's U.S. Unity node. Some 16 electrically-driven bolts will soon engage to firmly mount the 6.5-ton airlock to the station. And later this morning the spacewalkers will connect power cabling between the station and airlock to reactivate Quest's critical heaters.

0727 GMT (3:27 a.m. EDT)

The astronauts are tweaking the position of the robotic arm to fine-tune the alignment of the airlock relative to the station docking port.

0722 GMT (3:22 a.m. EDT)

As the airlock moved into the docking port only three of the four latch indicators engaged. The crew has to correct a slight misalignment to complete the capture.

0710 GMT (3:10 a.m. EDT)

Now four hours into today's spacewalk. The alignment verification for airlock installation is finally completed with Canadarm2 now moving again.

0635 GMT (2:35 a.m. EDT)

Canadarm2 operator Susan Helms is making final alignment checks to ensure the docking mechanisms on the airlock and station are properly lined up before the robot arm resumes moving Quest the final feet to installation.

0623 GMT (2:23 a.m. EDT)

The airlock is now in the so-called "pre-install" position, just a few feet away from its docking port.

0610 GMT (2:10 a.m. EDT)

Now three hours into today's spacewalk. The spacewalkers are currently just hanging out and enjoying the view on the Unity node as they await the airlock to move into position for attachment.

0545 GMT (1:45 a.m. EDT)

The "slow-motion ballet" of the station's robot arm to move the airlock continues smoothly. No problems have been reported during tonight's activities.

0527 GMT (1:27 a.m. EDT)

While the Canadarm2 continues to maneuver Quest, the spacewalkers have emerged from the shuttle's airlock sooner than planned and headed up to the station's Unity node. They made an inspection of the docking port where the Joint Airlock will be installed, looking for any debris left over from an antenna connector that broke around that area during a spacewalk during the last shuttle mission. No debris was found. Officials were worried such debris could have jammed the docking mechanism. The path is now clear for the airlock to be attached later this morning.

0510 GMT (1:10 a.m. EDT)

Riding on the end of the international space station's robot arm, the $164 million Joint Airlock "Quest" has begun moving out of Atlantis' payload bay. The 6.5-ton airlock will make an hour-plus trek from the shuttle to the starboard docking port of the station's U.S. Unity connection node where Quest will be attached.

0507 GMT (1:07 a.m. EDT)

All of the retention latches holding the airlock to Atlantis have been released. The station's arm is now free to lift the airlock out of the shuttle's payload bay.

0449 GMT (12:49 a.m. EDT)

The international space station's brand new robotic arm -- Canadarm2 -- has grappled the Joint Airlock riding in Atlantis' payload bay under the control of Expedition Two astronaut Susan Helms. Latches holding the airlock in place will now be released so the 58-foot arm can lift the 6.5-ton module out of the bay for the transfer to the station's open docking port on the side of the Unity node.

Meanwhile, the spacewalkers are retreating to Atlantis' airlock where they should spend about 45 minutes. Gernhardt explains why:

"The reason we're doing that is that we want to preserve our consumables in case this EVA goes long. Right now, it's planned for over seven hours, which is a long time, and of course it always has the threat of going longer, and so...we're going to be in the shuttle airlock on the umbilicals -- the service and coolant umbilicals -- just preserving our power and oxygen."

Once the airlock is in position for docking, the spacewalkers will head up the station stack to assist.

0425 GMT (12:25 a.m. EDT)

The spacewalkers have successfully completed the preparatory work to ready the Joint Airlock to be lifted out of Atlantis' payload bay and delivered to the international space station. Reilly is now stowing the "shower cap" cover, seal shields and disconnected power cabling. Soon both spacewalkers will return to the shuttle's airlock to hang out while the station's robotic arm hoists the Joint Airlock from the payload bay and maneuvers it into position for installation to the outpost.

0415 GMT (12:15 a.m. EDT)

The thermal clock is now counting for the astronauts. The spacewalkers have removed cabling running from Atlantis to the Joint Airlock which had provided power to the airlock's heaters since launch. The airlock will need to be hooked up to a similar power cable on the space station within the next few hours to ensure the water lines in the airlock don't freeze and rupture.

0412 GMT (12:12 a.m. EDT)

We have received confirmation that all three "towel bars" have been bolted to the airlock's hull by spacewalker Reilly. These are the fixtures are what the oxygen and nitrogen gas tanks will be attached to during the next two spacewalks. The bars couldn't be installed on the ground due to clearance issues with the shuttle's payload bay.

Also, Gernhardt has removed the covers from the airlock's docking mechanism seal.

0400 GMT (12:00 a.m. EDT)

For those of you keeping score at home, we have posted our updated spacewalk stats page.

0340 GMT (11:40 p.m. EDT Sat.)

The spacewalkers are now getting down to work. Gernhardt is removing a 12-foot wide thermal cover from the airlock -- called the "shower cap" -- that shields the module's docking mechanism that will attach to the station. He will then remove arc-shaped seal covers on the mechanism. Reilly, meanwhile, will install fixtures to the airlock that will allow the high-pressure gas tanks to be attached later on the mission.

0311 GMT (11:11 p.m. EDT Sat.)

EVA BEGINS. Astronauts Mike Gernhardt and Jim Reilly switched their spacesuits from shuttle-provided power to internal batteries at 11:10 p.m. EDT, signalling the official start of today's planned 7-hour spacewalk. The EVA is the 106th in U.S. space program history, the 65th to occur from the space shuttle, 22nd dedicated to international space station construction and first of third of Atlantis' current mission. This is Gernhardt's second EVA and Reilly's first.

The spacewalkers will soon float out of Atlantis' airlock and gather the tools and equipment needed for the initial chores of tonight's EVA. Over the next couple of hours the two men will ready the Joint Airlock for its removal from Atlantis' payload bay and subsequent docking to the international space station.

We will keep you posted on developments throughout the spacewalk and airlock installation with running updates throughout the night.

0258 GMT (10:58 p.m. EDT Sat.)

The airlock depressurization is now underway. Tonight's spacewalk should be in the next few minutes.

0235 GMT (10:35 p.m. EDT Sat.)

Subscribers of our Mission Theater can watch a movie giving a detailed preview of today's spacewalk. Crew wake-up from earlier this evening is also now available.

If you aren't a subscriber yet, here is how you can sign up! And click here for a complete listing of all the videos currently available to watch.

0220 GMT (10:20 p.m. EDT Sat.)

The spacewalkers are in the midst of a 75-minute procedure to breath pure oxygen in an effort to purge their blood streams of nitrogen to protect against "the bends" during today's excursion. That should wrap up shortly before the top of the hour. The 15-minute airlock depressurization will then follow. The spacewalk will officially start when the two crew members switch their suits to internal battery power -- expected aroun 11:10 p.m. EDT.

0122 GMT (9:22 p.m. EDT Sat.)

The spacewalkers are currently in the process of donning their spacesuits for the upcoming adventure outside Atlantis. However, the astronauts report activities are running nearly an hour behind schedule. So tonight's spacewalk likely won't begin until around 11 p.m.

Meanwhile, the shuttle and station robotic arms have been brought to life for use this evening. Atlantis' arm will be used to maneuver the spacewalkers around; the station's new Canadarm2 has the job of lifting the 6.5-ton airlock from the shuttle's payload bay and installing it on the station's Unity node.

SATURDAY, JULY 14, 2001
2330 GMT (7:30 p.m. EDT)

Mike Gernhardt and Jim Reilly have begun preparing for tonight's spacewalk to lend a hand in installing the Joint Airlock to the international space station. The 7-hour excursion is expected to start shortly after 10 p.m. EDT. In a pre-flight interview Reilly gave an overview of the spacewalk events:

"The first thing we have to do is basically pick up our tools and get ourselves set. We'll configure the shuttle arm so that we can put the Portable Foot Restraint on the arm, which is what I'll use to ride the arm. We'll also put some covers on there, which we put on, on EVA 2, on the airlock, we'll put that as one bundle on the arm and then there's another bag that's got some of the tools and things that we'll, that I'll be using, I'll hang that on the arm. And then we drive the arm over; while I go pick up the Portable Foot Restraint, Mike is then going down to get ready to remove some covers off of the airlock so that it will be ready for berth.

"As I go down the side with the Portable Foot Restraint, Mike is going back and what he does he's got two PFRs set up in the aft part of the payload bay, he'll be removing a very large shower cap-like device -- well, we actually call it the "shower cap" -- and what it is, is a contamination and thermal cover that covers the CBM, the joining mechanism for the airlock to the station, with that thermal cover. And it's a pretty big, it's like a, the best way to describe it would be like a, about a twelve-foot diameter, about an eight-foot, eight- or nine-foot diameter, Mylar balloon, you know, that he's got to pick up and carry it off; it's very similar to the one that Bob Curbeam took off on the Lab.

"After he completes that then he'll be taking off some contamination covers off the seal ring that forms the metal-to-metal seal with the Node, and once those are complete, by that point, I have been in the, I'll get in the arm, get in the PFR on the arm, drive back and then we have some guideposts and other attachment devices for the tanks that I'll be installing on the top of the equipment lock as you look at it in the payload bay. And once those are in place, then I'll go down, drop off the bag with the remaining items that will be installed on EVA 2 on the side of the crew lock, along with the covers which I've already installed; we'll then pick up the contamination covers and the thermal cover, the big thermal cover, bring all that stuff back and stow it in the tool stowage assembly, which is on the starboard side of the shuttle payload bay.

"Once that's complete then Mike and I basically get out and we give a "go" for unberth of the airlock, and that's when Susan and Jim pick up the airlock and take it up. In that period Mike and I are back in the shuttle airlock -- we get back on shuttle power and oxygen -- until the crew, or until the airlock is up and just about ready to be berthed. And once it's close then we'll egress the airlock on the shuttle again, then we'll climb up the stack of the Lab to the Node, and we'll be up there in case that Susan has a problem with mating the airlock.

"This will be the first time that the operators will not have a direct mating cue -- in other words, they won't have anything to look at like a centerline target that verifies exactly the alignment, so this'll be the first time that the Space Vision System, the SVS, which is the digital targeting software, will be used as the primary means of docking a module. So if there's any problem with that, Mike and I will be up there to give them external cues, but we don't expect they'll have any problems with that. So by the time we get there we expect that the airlock'll be in place.

"Mike will then attach some launch-to-activation cables, which will power the heater strings for the airlock, and while he's doing that I'll be picking up some Articulated Portable Foot Restraints, APFRs, and I'll be positioning those APFRs for our EVA 2, so when we're getting ready to dock our first tank. And that will be basically the end of the EVA; once that's complete then we'll go back down the stack to the shuttle, ingress the airlock, and that'll be the end of that first day outside."

2104 GMT (5:04 p.m. EDT)

The shuttle Atlantis have been awakened by Mission Control for Flight Day 4 -- the key day of this mission that will see the Joint Airlock attached to the international space station with the assistance by two spacewalking astronauts. See our flight plan for a timeline of tonight's activities.

0830 GMT (4:30 a.m. EDT)

Space shuttle Atlantis pulled up and latched ahold of the international space station while cruising 230 miles above South America on Friday night, kicking off a week-long visit that will see a $164 million airlock added to the orbiting outpost. See the full report.

0750 GMT (3:50 a.m. EDT)

The airlock install dress rehearsal is getting underway. Station astronaut Susan Helms has been using the Canadarm2 robotic arm to survey Atlantis' payload over the last hour. She will now practice the motions the arm will move through during the airlock installation process.

0537 GMT (1:37 a.m. EDT)

Subscribers of our Mission Theater can watch a video clip of today's hatch opening ceremony.

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0512 GMT (1:12 a.m. EDT)

See a snapshot of the hatch opening ceremony.

0500 GMT (1:00 a.m. EDT)

HATCH OPENING. The astronauts of space shuttle Atlantis and the international space station have been united with the opening of hatches between the two spacecraft. Greetings are underway inside the U.S. Destiny science lab of the station.

0445 GMT (12:45 a.m. EDT)

Astronauts aboard the shuttle and station are in the process of opening hatches between the two spacecraft.

0421 GMT (12:21 a.m. EDT)

Subscribers of our Mission Theater can watch a video clip of today's docking.

If you aren't a subscriber yet, here is how you can sign up!

And click here for a complete listing of all the videos currently available to watch.

0350 GMT (11:50 p.m. EDT Fri.)

The shuttle crew is performing the initial hatch leak checks following today's docking. And also the station's control-moment gyros have assumed attitude control of the ISS-shuttle stack, taking over from Atlantis.

0328 GMT (11:28 p.m. EDT Fri.)

The docking ring has been retracted and hooks have driven closed. The shuttle's docking mechanism is now being powered down.

Plans call for the hatches between the two spacecraft to be opened at around 12:30 a.m. EDT, followed by a welcoming ceremony. The big task still ahead for both the shuttle and station astronauts will be a robotic arm dress rehearsal of tomorrow night's airlock installation. The dry run test is expected to commence around 2:45 a.m.

0319 GMT (11:19 p.m. EDT Fri.)

See a snapshot of Atlantis docked to the international space station.

0312 GMT (11:12 p.m. EDT Fri.)

The extension ring on the shuttle's docking system is being retracted, bringing the international space station's docking port to a firm seal with Atlantis. The five astronauts aboard Atlantis and the three-person space station Expedition Two crew are now orbiting together in a single, joined spacecraft.

0309 GMT (11:09 p.m. EDT Fri.)

The docking occurred at 11:08 p.m. above northeastern South America. Currently, the rates between the shuttle and station are being damped out. Later the hooks and latches will be closed to firmly join the two spacecraft and Atlantis' Orbiter Docking System docking ring will be retracted.

0308 GMT (11:08 p.m. EDT Fri.)

CONTACT AND CAPTURE! Space shuttle Atlantis has docked to the international space station for a seven-day visit, marking the 10th U.S. mission to the outpost. Atlantis brings with it the Joint Airlock Quest to be attached to the station tomorrow night, giving the complex a gateway for American and Russian spacewalks.

Read our earlier status center coverage.