By Irene Klotz
CAPE CANAVERAL, Florida (Reuters) - Space shuttle Discovery eased away from the International Space Station on Wednesday, ending an eight-day visit that left the outpost with its first Japanese astronaut and enough power for full-time research and three more residents.
Shuttle commander Lee Archambault and pilot Tony Antonelli pulsed Discovery's steering jets at 3:53 p.m. EDT/7:53 p.m. British time to push the 100-ton spaceship out of its docking port.
Before leaving the station's orbit, Antonelli flew Discovery around the complex, which was outfitted during the shuttle's visit with a final set of glittering solar wing panels, making the station look like the illustrations that have been circulating around NASA for decades.
"You've made the space station much better than it was before," station commander Mike Fincke told the Discovery crew as they gathered to say good-bye.
Discovery's landing at the Kennedy Space Centre in Florida is scheduled for Saturday.
"It was really great having you up here," added Fincke, who, along with flight engineer Yury Lonchakov, will head back to Earth on April 7 after a six-month stay.
Their replacements, commander Gennady Padalka and flight engineer Michael Barratt -- along with space tourist Charles Simonyi, a former Microsoft executive flying for the second time -- are scheduled for launch on Thursday aboard a Russian Soyuz rocket from the Baikonur Cosmodrome in Kazakhstan.
The station's third crewmember, Koichi Wakata from Japan, is already aboard. He flew to the outpost with the shuttle Discovery crew, taking over for NASA astronaut Sandra Magnus.
"After four months up here and having a wonderful time, I'm looking forward to being outside," Magnus told reporters during an inflight interview."
STATION READIED FOR EXPANDED CREW
The primary goal of Discovery's flight, the first of five shuttle missions slated for this year, was to deliver the final segment of the space station's backbone -- a 31,000-pound (14,060-kg), $300 million (206 million pounds) girder that includes the last of four U.S.-built solar panel wings.
The power boost will provide enough electricity to double the number of medical, materials science, fluid physics and other experiments that can be conducted in the station's three laboratories.
To handle the extra work, the United States and its 15 space station partners plan to add another three astronauts to the three-member resident crew.
If schedules hold, another Soyuz rocket will blast off in May with the first expanded crew. NASA's next shuttle mission to the station, slated for June, is to install a Japanese-built porch for its Kibo complex so experiments can be directly exposed to the space environment.
The Discovery crew also delivered a new part to fix the station's water recycling system that purifies urine and condensate into water, which can be used for drinking or split into hydrogen and oxygen, for breathing.
The shuttle will bring home samples from the station's water system for analysis on Earth. NASA will not clear the station crew to use the water until that work is finished, though managers said there is enough water in storage aboard the outpost to proceed with expanding the crew.
With shuttle missions coming to an end -- and with that the ability to supply the station with water, which is a by-product of the shuttle's electrical generators -- the recycler is considered crucial to the station's long-term viability.
NASA plans to retire its shuttle fleet next year and develop a new fleet of spaceships, called Orion, that can fly to the moon as well as ferry crews to the space station, which orbits about 220 miles (355 km) above the planet.
(Editing by Jim Loney)