Shuttle Endeavour heads home after shorter, successful mission

CAPE CANAVERAL (AFP) - NASA cleared the shuttle Endeavour for landing on Tuesday, after a two-week mission to the International Space Station (ISS) was cut short 24 hours by menacing Hurricane Dean.

Landing was initially set for Wednesday, but the US space agency rescheduled it for Tuesday fearing that its control center in Houston, Texas may have to be evacuated if it is grazed by Hurricane Dean, now roaring across the Caribbean.

The hurricane, on track to strike Mexico early Tuesday but missing Texas altogether, "poses little hazard or little risk to the Johnson Space Center mission control area," NASA said in a statement.

Nevertheless, it added, "mission managers continue to monitor Hurricane Dean as it moves westward."

Endeavour is to land at the Kennedy Space Center in Cape Canaveral, Florida, which is less well equipped than Houston for ground control operations in the event the Johson Space Center has to be shut down if the hurricane strikes.

The Endeavour crew will have two chances to land -- at 12:32 pm (1632 GMT) and 2:06 pm (1806 GMT), the National Aeronautics and Space Administration said.

The weather forecast for Tuesday at the Cape was relatively dry and any possible showers "probably not expected to be a concern ... so the weather looks good" for a landing, said NASA spokesman Mike Curie in Houston.

Should landing here be called off, the shuttle would try again on Wednesday first at Cape Canaveral, or alternatively at Edwards Air Force Base in California, or possibly at the White Sands Space Harbor in New Mexico.

The Endeavour and ISS crews finished a shortened, fourth spacewalk on Sunday, before the shuttle with its crew of seven undocked from the ISS without performing the usual fly-past of the station to take pictures.

"They didn't do a flight around the ISS because it was a very busy day for the crew, undocking and doing the late inspection, all of this in one day," Curie said.

The crew last week put out a robotic arm with a high-definition camera and laser on the end to inspect the heat shield on Endeavour's nose and wings for possible damage from meteors and other floating space debris.

Safety has been a big concern on space missions since 2003 when the shuttle Columbia exploded on re-entry due to a damaged heat tile. All seven astronauts died and missions were put on hold for two and a half years.

Endeavour sustained similar damage when taking off on August 8: a small gash near a landing gear hatch, made 58 seconds after liftoff by a piece of foam that broke off the external fuel tank and was possibly accompanied by some ice.

Astronauts inspected the damage during their stay at the space station and NASA, after long deliberation, decided on Thursday that it was not necessary to do risky repairs in space.

NASA will not launch the next two shuttles planned in October and December of this year without first fixing the source of the foam problem, even if that means delaying the launches, shuttle program manager Wayne Hale said.

In nine days at the space station, Endeavour crew and a US astronaut posted at the ISS, Clayton Anderson, made four spacewalks, installing a mechanical truss on the orbiting laboratory and fixing one of the gyroscopes that keeps it stable. They also delivered 2.7 tonnes of supplies.

It was NASA's second mission of the year, and came after a series of embarrassing scandals including an astronaut charged with plotting against a love rival and reports of others turning up drunk for flights.

The agency in a statement Monday put a positive face on the latest outing, saying the stay at the ISS had been "successful."

The mission also had a feel-good human element: crew member Barbara Morgan became the first teacher in space, 21 years after the first "educator astronaut" perished in the 1986 Challenger shuttle explosion.

Morgan even gave a lesson from space, answering questions from school children in Iowa in a broadcast from the station.

NASA plans at least 12 more missions to the ISS by 2010, when its three shuttles are due to be taken out of service.

The 100-billion-dollar ISS project involves 16 countries and is seen by NASA as a key step to putting humans back on the moon and possibly Mars.