By Irene Klotz
Houston - Shuttle Discovery astronauts said goodbye to the International Space Station crew on Tuesday, ending a nine-day mission to deliver a Japanese-made orbital research laboratory.
"I can hardly believe this time has come. It's been an amazing adventure," said astronaut Greg Chamitoff, who is staying behind on the station for six months. "I'm looking forward to the adventure ahead."
Chamitoff replaces station flight engineer Garrett Reisman, who has been in orbit since March.
"I managed not to break anything really expensive," Reisman joked as the crews gathered for a farewell ceremony.
"(The station) really is something straight out of science fiction. When you take a look around it's just really impressive that we've pulled this off," he said
With the addition of Japan's 37-foot-long Kibo laboratory, the station has more room than a jumbo jet.
"There's actually enough space so that you can lose people. You can go from stem to stern trying to find somebody and not find them. That's how big this place is," Reisman said.
It is much tighter inside space shuttle Discovery where Reisman, six US astronauts and Japan's Akihiko Hoshide will spend the next three days. The shuttle is scheduled to depart the station on Wednesday and land at the Kennedy Space Centre in Florida on Saturday.
In addition to packing gear and testing Discovery's landing systems, the crew plans to use a laser-studded boom to scour their ship's wings and nose cap for damage.
The inspection normally is conducted the day after launch, but Discovery's payload bay was so full there was no room for the boom.
During the first of the mission's three spacewalks, astronauts retrieved an inspection boom that had been left behind on the station by the last shuttle crew. Nasa implemented the inspections as a safety check following the 2003 Columbia disaster.
There is plenty of room in Discovery's cargo bay for the 50-foot-long boom now. The 32-ton Kibo module was attached to the station and outfitted by the Discovery crew.
A flight to add an external platform on Kibo for telescopes and science experiments is scheduled for in 2009.
Nasa has nine more flights to complete assembly and resupply of the station by 2010, when the shuttle fleet is due to be retired. The agency also plans a final servicing call to the Hubble Space Telescope in October.
(Editing by Dan Whitcomb and Alan Elsner)