KENNEDY SPACE CENTER, Fla.--The crew of the shuttle Discovery, given a "Star Trek" send off by actor William Shatner, undocked from the International Space Station early today to close out an extended assembly and resupply mission, the shuttle's 13th and final visit to the orbital outpost.
With pilot Eric Boe at the controls, Discovery's docking system disengaged from the station's forward port at 7 a.m. ET as the two spacecraft sailed through orbital darkness above the western Pacific Ocean northeast of Australia.
"Houston and station, physical separation," commander Steven Lindsey called as the orbiter began backing away.
Manually guiding the shuttle to a point about 400 feet directly in front of the lab complex, Boe kicked off a 360-degree fly-around, looping up over, behind, and below the space station to capture photographs and video showing a final U.S. module in place, along with a full complement of visiting spacecraft from Europe, Japan, and Russia.
NASA managers earlier asked their Russian counterparts to consider undocking a Soyuz spacecraft for a fly-about to capture views of the station with Discovery attached. But Russian mission managers, citing technical considerations, declined.
Discovery's fly-around took a little more than an hour to complete. At 8:09 a.m. ET, the ship's maneuvering jets were fired in the first of two maneuvers to break away and leave the area.
"Steve, as you guys are heading home, I wanted to say one last time that we really enjoyed your company onboard," radioed Expedition 26 Commander Scott Kelly, who is scheduled to return to Earth March 16 aboard a Russian Soyuz spacecraft.
"Doing something as complicated as this really takes a team effort and that's, I think, what we've proven here this last week. I'd like to wish you guys a safe rest of your fight and a safe landing. And I will see you all back in Houston here in about a week or so."
"Hey Scott, I couldn't agree more, I think the team effort between our two crews and the larger ground team that planned this and put it all together enabled us to get well over 100 percent of our objectives," Lindsey replied. "It's been a pleasure working with your team and I look forward to seeing you guys. Have safe travels for everybody on board and we will see you in about a week."
"OK, take care," Kelly called. "Station out."
Over the course of an extended docked mission, the Discovery astronauts delivered a new storage module, an external spare parts platform, an extra set of radiator panels and several tons of supplies, science gear, and other equipment. They also staged two spacewalks to perform a variety of maintenance tasks outside the station and helped out with work to service one of the station's oxygen generators and a carbon dioxide removal system.
Throughout it all, Discovery performed flawlessly, allowing mission planners to extend the docked mission by two days.
"I think if I had to step back and characterize this entire mission, I would really call it an above-and-beyond mission." said Kenneth Todd, chairman of the space station Mission Management Team. "The systems performed very, very well to the point where we were able to add a couple of extra days, which we just don't do that often...Being able to get that work behind us now with a larger crew was very, very helpful for us."
But watching Discovery depart early Monday, he said, was a bittersweet moment.
"To see Discovery leave, she had done just a flawless mission for us in support of the program, and yet as she was backing away it was clear to us that that was the last time she was going to visit us," he said. "So we bid her adieu and certainly Godspeed to Steve and the rest of the crew on the way home."
Lindsey, Boe, and their crewmates--Nicole Stott, Michael Barratt, and spacewalkers Stephen Bowen and Alvin Drew--got in the proper spirit for undocking with a 3:23 a.m. ET wake-up song from Houston that was voted the second most popular in a NASA contest: the Alexander Courage theme from the 1960s television series "Star Trek."
As with the original, Shatner began with the familiar phrase "Space...the final frontier." But the rest was a tribute to Discovery, making its 39th and final flight since its maiden launch in 1984.
"Space...the final frontier," Shatner said as the music played. "These have been the voyages of the space shuttle Discovery. Her 30-year mission: to seek out new science, to build new outposts, to bring nations together on the final frontier, to boldly go and do what no spacecraft has done before."
"And good morning, Houston," Lindsey replied when the music faded. "And that was, I believe, the second most popular selection from the song contest for the space shuttle program and I'd like to thank William Shatner for taking the time to record that special introduction for us."
The song voted most popular in the wake-up music contest--"Blue Sky" by Big Head Todd and the Monsters--will be beamed up to the astronauts Tuesday.
The rest of the shuttle crew's day was devoted to carrying out a final inspection of the shuttle's reinforced carbon nose cap and wing leading edge panels to look for any signs of impact damage from micrometeoroids or orbital debris since a similar inspection the day after launch.
The so-called "late inspection" was completed around 3:45 p.m. ET. Analysts at the Johnson Space Center in Houston will review photos and laser scans to make sure the heat shield is in good shape for re-entry.
The astronauts plan to pack up and test Discovery's re-entry systems Tuesday before dropping out of orbit and landing back at the Kennedy Space Center around noon Wednesday.