A space shuttle left the International Space Station for the last time Tuesday, heading home to end the 30-year run of a vessel that kept astronauts flying to and from orbit longer than any other U.S. rocketship.
Atlantis slipped away as the two spacecraft soared about 400 kilometres above the Pacific.
All that remains of NASA's final shuttle voyage is the touchdown, targeted for the pre-dawn hours of Thursday back home in Florida.
As a final salute, the space station was rotating 90 degrees to provide never-before-seen views of the complex. The shuttle and its crew of four were to fly halfway around the station, cameras whirring aboard both vessels to record the historic event.
Emotions ran high, both in orbit and at Mission Control. The naval ship's bell aboard the space station chimed three times as Atlantis slowly backed away.
"Atlantis departing the International Space Station for the last time," announced space station astronaut Ronald Garan Jr.
"We'll miss you guys. Godspeed."
Shuttle commander Christopher Ferguson thanked the six station residents for their hospitality, then added:
"We'll never forget the role the space shuttle played in its creation. Like a proud parent, we anticipate great things to follow ... Farewell, ISS. Make us proud."
Flight controllers savoured the dual TV images of the shuttle, the last ever seen from orbit, and the station. Mission Control called it the second-best view on Earth.
"It must look pretty spectacular," Ferguson replied.
And it was: Atlantis sailing serenely against the black void of space, its payload bay wide open, and the space station, its huge solar wings glowing golden in the sunlight.
Year's worth of supplies left behind
Atlantis spent 8½ days at the space station and left behind a year's worth of supplies, insurance in the event commercial providers encounter delays in launching their own cargo ships.
It was the 37th shuttle mission, over more than 12 years, dedicated to building and maintaining the space station — the largest structure ever to orbit the planet. All told, shuttles spent 276 days, or nearly 40 weeks, docked to the station. It's now a sprawling complex with multiple science labs — 13 rooms in all and more than 408,000 kilograms of mass, most of that delivered by shuttles.
With the retirement of the shuttle fleet, the space station now must rely solely on other countries for restocking, at least until the first privately funded rocket blasts off with a load. That could come by year's end.
Astronaut launches from U.S. soil, however, are three to five years away, at best. Until then, Americans will continue flying to and from the space station via Russian Soyuz capsules at a hefty price.
Before leaving, the Atlantis crew gave their station colleagues a small U.S. flag that flew on the inaugural shuttle voyage in 1981. The flag is the prize for the first rocket maker that brings Americans back to the station, launching from America.
U.S. President Barack Obama described it last week as "a capture-the-flag moment here for commercial spaceflight."
Obama wants private companies taking over Earth-to-orbit operations so NASA can concentrate on sending astronauts beyond.
The goals: an asteroid by 2025 and Mars by the mid-2030s.
As for NASA's three shuttles, they will become museum displays.
Atlantis will join Discovery and Endeavour in retirement after this 13-day journey, the 135th for the shuttle program.