Shuttle Endeavour pulled away from the international space station on Monday and headed for home after a heartfelt farewell between the two crews.
It culminated 12 days of shared work, the longest mission ever of its kind.
The 10 space travelers performed a record-tying five spacewalks, put together a space station robot and provided a new Japanese compartment — and resident — for the orbiting complex.
"In my mind, in my view, it's been an extraordinary mission," said LeRoy Cain, chairman of the mission management team. "It's just been a textbook mission up and down the line in every way that I look at it."
Before the hatches were closed in the late afternoon, a few hours before the shuttle's undocking, astronaut Garrett Reisman pretended he was going to float into Endeavour. Space station commander Peggy Whitson grabbed him around the waist and pulled him back.
"I already feel the nostalgia coming on about the (shuttle) crew," Reisman said.
Reisman flew up aboard Endeavour to replace French astronaut Leopold Eyharts, who was going home on the shuttle. They embraced and patted each others' backs as they parted company; the other astronauts did the same.
"Up to you, Garrett. It's your turn," said Eyharts, who spent 1 1/2 months at the space station, less time than planned because of the previous shuttle flight's delay in getting him there. "C'est la vie."
Endeavour, Eyharts and six others are due back on Earth on Wednesday evening. It will wind up a 16-day trip for the shuttle.
Slideshow 12 photos
Month in Space: January 2014
The three astronauts left behind on the space station, meanwhile, won't have time to get bored.
Europe's new cargo carrier, Jules Verne, will dock April 3; it blasted into orbit this month. One week later, a Russian Soyuz spacecraft will arrive, carrying a fresh space station crew.
NASA's next visit will be in late May. That's when Discovery is due to arrive with the Japanese lab, Kibo, which means hope. Endeavour delivered the first section of the lab, a storage compartment.
But the Hubble Space Telescope mission, at the end of August, might wind up being postponed because of a slowdown in shuttle fuel-tank production.
Only now, five years after the Columbia accident, are fuel tanks and their insulating foam skin being built from scratch, Cain noted. The fuel tank used to propel Endeavour into orbit on March 11 was the last one that was already in production when Columbia was destroyed, and so it was easier to make the post-accident safety changes.
These changes, most if not all of them involving foam, took time to refine. NASA also became bogged down by a recurring fuel-gauge problem that finally was resolved a few months ago.
"We're on a learning curve here," Cain said.