After eight days together, space shuttle Discovery pulled away from the international space station Wednesday, ending a successful effort to boost electrical power and science research at the orbiting outpost.
The two spacecraft went separate ways as they soared above the Indian Ocean. The undocking puts Discovery and its seven-member crew on course for a Saturday touchdown.
"Godspeed," called out the space station's skipper, Mike Fincke. He added: "Come again."
NASA was eager to see the space station with its new glistening pair of solar wings following Discovery's departure. The shuttle took a victory lap around the station, primarily for picture-taking. But because there was no television availability during the flyaround, Mission Control and the rest of the world had to wait for the astronauts to beam down the recorded video views.
With the installation last week of the final set of solar wings, the space station finally resembles the artist renderings from years past, balanced with four wings on both sides.
NASA expects the extra electrical power to drastically increase the amount of research in the various labs that make up the 220-mile-high outpost.
"You made the space station much better than it was before," Fincke told the shuttle astronauts just before their departure. "You gave us more power, symmetry - which is not to be underrated - and you gave us a new crew member."
That new member, Japanese astronaut Koichi Wakata, remained behind on the space station with Fincke and a Russian cosmonaut.
Sandra Magnus, whom Wakata replaced, kept waving as she disappeared down the hatch and floated into Discovery. Wednesday marked her 131st day in space; she moved into the space station in mid-November.
"All of you guys, this is the toughest part of the mission, at least for me," Fincke said. "On one hand, it's a moment of triumph ... and yet on the other hand, we're going to really be missing you."
The two crews embraced as they said goodbye.
Fincke and his crew will be getting company again in just a few days. A Russian Soyuz rocket is set to lift off Thursday with two new station crewmates and a billionaire tourist along for the ride; they'll arrive this weekend. Fincke then will return to Earth with Microsoft Word and Excel developer Charles Simonyi and cosmonaut Yuri Lonchakov.
"Have happy travels, and let's get together when you get back," shuttle commander Lee Archambault told Fincke.
Discovery is bringing back five months' worth of experiments from the space station. The blood, urine and saliva samples need to be kept cold for as long as possible, and remained in the station freezer until the last possible moment.
The astronauts stuffed the shuttle freezer with as many samples as possible, and wrapped the remaining specimens in ice packs.
Discovery also is returning four to five liters of recycled water made from the astronauts' urine and sweat. NASA wants to make sure the water is safe before space station astronauts start drinking it there.
The reclaimed water is an essential part of NASA's plan to double the size of the space station crew, to six, in just another two months.
Discovery supplied the space station with a new urine processor to replace the original one, which malfunctioned.