This story was updated at 5:35 p.m. EDT.
The space shuttle Discovery and its crew of seven astronauts cast off from the International Space Station on Wednesday after an eight-day visit that boosted the orbiting lab to full power.
Discovery undocked from the space station at about 3:53 p.m. EDT (1953 GMT) as the spacecraft flew 216 miles (347 km) above the Indian Ocean. A camera aboard the shuttle beamed views of the space station's new solar wings back to Earth.
?You look clean and dry,? station skipper Michael Fincke told the shuttle crew after undocking as they passed over Houston, home of NASA?s Mission Control. ?What a beautiful sight.?
Discovery?s crew delivered the station?s last of four U.S. solar arrays, unfurling them to their 240-foot (73-meter) wingspan to complete the outpost?s power grid. The new wings balanced out the station, giving it two solar arrays per side, each with four expansive wings.
?We?re very proud to have left the space station with more power,? Discovery commander Lee Archambault said before leaving the outpost.
Discovery slowly pulled away toward a point about 600 feet (182 meters) from the station, where pilot Dominic ?Tony? Antonelli flew it around the station in a victory lap so his crewmates could snap their first photographs of the outpost?s new look.
?I?d like to say thank you and your crew for an outstanding mission,? Fincke told Archambault before the shuttle departed. ?You made the space station much better than it was before. You gave it more power and symmetry, which is not to be underrated.?
Station at full power
The new solar arrays boosted the station?s power grid by 25 percent, leaving the outpost capable of generating enough electricity to power a neighborhood of 42 average size homes. The space station will need that extra power to support its planned shift to six-person crews- double the current size - later this year.
Discovery also delivered last piece of the space station?s backbone-like main truss, which now extends more than a football field in length and can easily be spotted from Earth by the naked eye.
The space station is now 81 percent complete and weighs nearly 1 million pounds (453,592 kg), with up to eight more shuttle missions planned to finish its construction by 2010. NASA has reserved a ninth shuttle flight to overhaul the Hubble Space Telescope in May.
While Discovery was docked at the station, astronauts installed a vital spare part for the space station?s urine recycler during the joint mission.
The recycler is part of a larger system to convert astronaut urine, sweat, condensation from the outpost?s atmosphere and other wastewater back into pure water for drinking, food preparation and other uses. The system is vital for the space station to support larger crews for the long-term, and Discovery is returning four or five liters of recycled water for analysis on Earth.
The shuttle is also bringing home about five months? worth of blood and other biological samples from experiments, many of them conducted by NASA astronaut Sandra Magnus, who is also returning to Earth aboard Discovery.
Magnus is wrapping up a 4 1/2-month mission to the station and was replaced by Japanese astronaut Koichi Wakata, who will stay aboard the station for three months as Japan?s first long-duration spaceflyer.
As the two crews bid farewell to Each other, Magnus lingered by the hatches between Discovery and the station, waving some last-minute goodbyes to Fincke and fellow crewmate Yury Lonchakov of Russia.
?It?s been a very memorable time up here, and I guess I?m leaving with a sense of satisfaction that we did get so much done,? Magnus said before leaving the station.
Discovery?s undocking comes one day before the planned launch of a new station crew and American billionaire Charles Simonyi - the world?s first repeat space tourist - who is paying about $35 million for his second trip into orbit.
The new station crew and Simonyi are due to launch toward the station Thursday aboard a Russian Soyuz spacecraft and arrive on Saturday, just hours before Discovery?s planned landing in Florida.
SPACE.com is providing continuous coverage of STS-119 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.
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