NASA animation shows the P6 truss being hoisted into position for mounting to the international space station while the spacewalkers are getting into position. Photo: NASA TV/Spaceflight Now

Tanner and Noriega will begin their first spacewalk, or EVA, around 2 p.m. EST on Dec. 3, the day after docking. As the spacewalkers leave Endeavour's airlock, Garneau will use the robot arm to move the P6 array into a "pre-install" position with the base of the long spacer about three feet above the top of the Z1 truss.

At that point, the crew will face the first of several deadlines: If the P6 truss is not installed within the next 10 hours or so, critical systems could be damaged by thermal problems.

Tanner and Noriega will position themselves on opposite sides of the Z1 truss so they can see the mating interface and provide verbal cues to Garneau to help him precisely align the array truss. He will not be able to directly see that interface from inside the shuttle's crew cabin as he slowly lowers the P6 truss to within a few inches of the Z1 capture plate.

But Tanner and Noriega will provide a bird's eye view of the operation using a new wireless video system and small spacesuit TV cameras equipped with wide-angle lenses.

"We call them the Joecam and the Carloscam," Tanner joked. "You'll be able to see exactly what we're seeing. ... This is going to be real thrilling, it's a tremendous EVA tool.

Once the P6 truss is properly positioned, Tanner and Noriega will engage a large mechanical claw built into the top of the Z1 truss.

"It is a manually operated claw by the EVA astronauts," Reeves said. "They will crank the claw closed to capture (a) capture bar on P6 and pull it down and have a solid mate between Z1 and P6. At that point, the EVA crew will go to each corner of P6 and install a bolt that will hold P6 to Z1 permanently."

There are three bolts at each corner, a prime and two backups. Only the prime is required to firmly lock the array truss to Z1.

The new P6 truss towers above the international space station. Photo: NASA

Once that work is done, Noriega will anchor his feet to a work platform on the end of the robot arm, now operated by pilot Bloomfield, and begin connecting various electrical cables between P6 and the Z1 truss.

Tanner and Noriega then will "proceed up the stack, up P6, to unlatch the launch restraints on the solar array blanket boxes," Reeves said. "They will unlatch those restraints and it is at that point P6 can no longer be returned to Earth in the shuttle."

"So we are committed, after we get the four bolts in and we release the attach points on the solar array blanket boxes, to leaving P6 on orbit."

Whether it is left in orbit attached to the station or jettisoned depends on the success or failure of the crew's efforts to deploy the two big solar wings over the next two hours.

Noriega and Tanner will manually crank out the two solar array blanket boxes from their stowed positions against the side of the truss module. The next task will be to rotate each array boom canister to the solar wing unfurl position.

Before the arrays are deployed, however, Tanner and Noriega will release launch restraints on the P6 radiator assembly that will enable it to be extended during the lab installation mission in late January.

"Once they've completed all of that activity, they will go back to the airlock, go inside the airlock and go back on the umbilicals to the shuttle," Reeves said.

NASA animation shows arrays beginning to deploy. Only one side will extend at a time, however. Photo: NASA TV/Spaceflight Now

"We will keep them there to extend their EVA time if we need them. And it's at that point that the ground and the crew on board the shuttle will begin the commanding for the deployment of the solar array wings."

Jett will send the actual array deployment commands from a computer on Endeavour's flight deck. Only a full extension is allowed. Should one two-panel wing jam and fail to fully deploy, the wing likely would be jettisoned. While the station can operate with just one fully deployed wing, both will be needed down the road.

"If anything should go wrong, we have the (spacewalkers) ready to go out and assist," Reeves said. "But we're also in a safe configuration for the night if we need to work a problem and be ready to go out the next day.

"Once we're satisfied we don't have a major contingency that requires immediate attention, the crew will go ahead and close out the airlock, come inside and post-flight the suits."

But Tanner and Noriega will no doubt take time to enjoy the view of the arrays towering above the shuttle's open cargo bay.

"I think the view is going to be absolutely fantastic," Tanner said. "These things are huge, they're quite colorful and I think the view from th cameras in the crew module is going to be fantastic. Once the arrays are out, the station becomes the third brightest star in the heavens."

The solar arrays are fully extended to generate much-needed power for the space station as seen in NASA animation. Photo: NASA TV/Spaceflight Now

Venus is the brightest "star" in the night sky, reaching a magnitude of -4.3. It is outshone only by the sun and moon. Jupiter, currently at magnitude -2.69, is second while Sirius, at magnitude -1.47, is the brightest true star in the sky.

One assumes, based on Tanner's remarks, that the station will outshine Sirius, ranking third behind Venus and Jupiter. But other NASA officials have thrown the moon into the mix and it's not clear where the station actually ranks in apparent magnitude.

But it is certainly correct to say the outpost will be one of the brightest objects in the night sky once the highly reflective P6 arrays are deployed.

"The most thrilling time for both of us is going to be on the very top of P6," Tanner said. "We're over 85 feet from the sill (sidewall) of the orbiter. We spend a fair amount of time at the top of P6, working hard, of course, but enjoying the view. I think that's going to be fantastic."

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