Shuttle astronauts prepare for Wednesday landing

HOUSTON (Reuters) - Shuttle Endeavour astronauts stowed gear and tested flight systems ahead of Wednesday's return to Earth that will end what NASA hailed as a landmark mission to the International Space Station.

The seven crewmembers ran through the usual pre-landing checks on Tuesday, including a test of steering jets that will help guide Endeavour to a scheduled touchdown at 7:05 p.m. EDT on Wednesday at Kennedy Space Center in Florida.

"No evidence of any problems, all the jets look good," flight commentator John Ira Petty said from Mission Control.

The shuttle, which lifted off on March 11 and spent 12 days at the International Space Station, delivered the first segment of Japan's three-piece Kibo laboratory and a Canadian-built maintenance robot named Dextre.

The main segment of Kibo, which will be the station's largest lab when completed early next year, is scheduled for transport to the outpost on a shuttle flight in May. Kibo is Japanese for "hope."

Kibo's arrival marked the first time that all 15 partner nations in the $100 billion project have had a facility on the space station, the first segment of which was launched into orbit in November 1998.

"So this is a fabulous moment for us," NASA space station program manager Mike Suffredini said in a Monday night press briefing.

"It is without a doubt the largest, most technologically challenging international project ever undertaken by humankind, and we as a people ought to be proud of where we are."

MORE SHUTTLE FLIGHTS

He said the space station was about 70 percent complete. NASA, the U.S. space agency, plans 10 more shuttle flights to expand and supply the outpost before the aging shuttle fleet is retired in 2010.

Before the station can be finished, NASA must come up with a fix for a balky rotary joint that points one of the outpost's solar panels at the sun to maximize electricity production.

NASA has sent several spacewalkers, including Mike Foreman on this flight, to examine the joint and has concluded that something is grinding as it moves, Suffredini said.

Still unknown, he said, was why it was happening.

NASA has locked the joint in place to prevent further damage but will need maximum power from the panel as station assembly continues.

Suffredini said there was sufficient electricity to fully power the station until the third piece of Kibo is delivered in 2009.

"That's probably the next bump we have in the road," he said.

(Editing by John O'Callaghan)