KENNEDY SPACE CENTER, Fla.--After 37 space station assembly flights over the past 12 and a half years, the shuttle Atlantis undocked from the lab complex for the final time today in a long-awaited milestone that marks the beginning of the end for NASA's last shuttle mission.
With pilot Douglas "Chunky" Hurley at the controls, Atlantis pulled away from the station's forward docking port at 2:28 a.m. EDT as the two spacecraft sailed through orbital darkness 243 miles above the Pacific Ocean east of Christchurch, New Zealand.
"Physical separation, Houston," commander Christopher Ferguson radioed as the shuttle pulled away.
A few moments later, space station flight engineer Ronald Garan rang the ship's bell in the Harmony module, saying "Atlantis, departing the International Space Station for the last time."
"Thank you for your 12 docked missions to the ISS and for capping off 37 space shuttle missions to construct this incredible orbiting research facility," he said. "We'll miss you guys. Godspeed, soft landing, and we'll see you back on Earth in the fall."
"Thank you, Ron, and to the station commander Andrey Borisenko, we appreciate your hospitality," Ferguson radioed. "What a generation can accomplish is a great thing. It's got a right to stand back and for just a moment, admire and take pride in its work. From our unique vantage point right here perched above the Earth, we can see the International Space Station as a wonderful accomplishment...Farewell, ISS. Make us proud."
After moving to a point about 600 feet directly in front of the orbital laboratory, Hurley paused for about a half hour while the station carried out a 90-degree yaw maneuver, lining up with the long axis of its solar power truss aimed at the shuttle.
"And station, Atlantis, you'll be happy to know you look just as good from the side as you do from the front," Ferguson radioed.
"Thanks, Fergie," Garan replied. "Not sure how to answer that one, but thanks."
"Hey, and that's our good side," quipped station flight engineer Michael Fossum.
The station normally is oriented with the truss at right angles to the lab's direction of travel and departing shuttles typically loop around the axis formed by the station's pressurized modules before leaving the area. But for this final departure, flight controllers gave the shuttle a different view to provide better photo documentation of the station's extremities.
"We'll be coming out underneath you and you should have a good view from the cupola," Ferguson radioed. "I'm not sure when we're going to break down the big loop (communications circuit), but if it's anytime soon we just wanted to give you a final goodbye."
"Hey thanks, Fergie, we'll be watching you from the SM (service module) windows," Garan replied. "You guys looked really good on the fly-around from what we can see. Again, thank you so much for all you guys have done for us up here. We really, really appreciate it."
With Atlantis' on-time departure, space shuttles have spent 276 days, 11 hours, and 23 minutes docked to the station since construction began in 1998, or more than nine months all together. Space station veteran Dan Tani called Atlantis from the lab's mission control center to say farewell.
"Hey Fergie, from the ULF-7 Orbit 1 team in the ISS mission control room here in Houston, we just wanted to let you know it's been a pleasure and an honor to support this, the 37th mission of the space shuttle to the ISS," he said. "We're proud to be the last in a countless line of mission control teams that have had the honor to watch over the ISS while Discovery, Endeavour, and Atlantis have visited over the last 13 years.
"From this room, we've watched and supported as the shuttle has enabled the station to grow from a humble single module that was grappled by the shuttle's arm, to a stunning facility that is so large some astronauts have even momentarily gotten lost in it. Of course, the ISS wouldn't be here without the space shuttle, so while we have the communication link up for the last time, we wanted to say thank you and farewell to the magnificent machines that delivered, assembled, and staffed our world class laboratory in space."
With the station undocking behind them, Ferguson, Hurley, Sandra Magnus, and Rex Walheim carried out a final heat shield inspection, looking for any signs of damage that might have occurred since a similar inspection the day after launch. They will test the shuttle re-entry systems tomorrow, pack up, and set their sights on re-entry Thursday and landing back at the Kennedy Space Center around 5:56 a.m. Good weather is expected.
The Atlantis astronauts left a flag behind on the space station that was first carried into orbit aboard the shuttle Columbia during the first shuttle mission in 1981. The flag will remain in place until U.S. astronauts, launched on new commercial spacecraft, retrieve it later this decade, a gap of uncertain duration.
Before Atlantis undocked, Tani tried to put that in perspective during a morning chat with space station flight engineer Ronald Garan.
"Today is the 36th anniversary of the undocking of the Apollo from the Soyuz at the end of the Apollo-Soyuz Test Program mission," Tani said from mission control in Houston. "The Apollo landing, which was two days later just like shuttle's, marked the beginning of the gap during which time the U.S. did not have any manned launches. That gap was closed five years and nine months later with the launch of (Columbia on) STS-1. So that's our mark to beat -- five years and nine months. We'll start the clock."
"All right, we just (started) our clock," Garan replied. "Thanks."
The inspection of the shuttle's reinforced carbon nose cap and wing leading edge panels is a standard feature of post-Columbia shuttle missions. As always, the shuttle's Canadian-built robot arm used an instrumented boom to scan the nose cap and wing leading edge panels, which experience the most extreme heating during re-entry.
In yet another bittersweet milestone for NASA, the inspection marked the final use of the 50-foot-long robot arm, a technological marvel that gave the shuttle its unique ability to precisely position spacewalking astronauts, to deploy and retrieve satellites like the Hubble Space Telescope, and to assemble the International Space Station.
Over the past three decades, experiencing virtually no technical problems, the robot arm deployed or retrieved seven satellites, assisted in 115 spacewalks, delivered 30 space station components, and grappled 72 payloads. Shortly after today's heat shield inspection, the arm was powered down for the last time, bringing Canada's hugely successful contribution to the shuttle program to a close.
Lead Flight Director Kwatsi Alibaruho's team in mission control ended its final shift around 6:30 a.m. Entry Flight Director Tony Ceccacci and his team will take over tomorrow to prepare for landing.
"Thanks for hanging with us for this week and a half or so. It's really been fantastic working with you," Ferguson radioed. "We promise we'll finish up in style here and see you back at JSC (Johnson Space Center) in a couple of days."
"Hey thanks, Fergie, as you mentioned it's the very last MCC shift for virtually all of us here, and we've got lots of words we'd love to say and we'll save then until you're safely back home," replied astronaut Steve Robinson in mission control. "We'll just say we're proud of you, we're proud of NASA, we're proud of our nation. Safe travels, and see you back home."
"That was great, Stevie Ray, thanks so much," Ferguson said. "You know, when you walk out the door of MCC there, turn around and make a memory."
"Safe flight home, Atlantis," Robinson said.