The space shuttle Discovery and its seven-member crew have returned to Earth after a successful eight-day mission to repair the Hubble telescope.

Air Force Colonel Curtis Brown landed the shuttle at 1901 EST (0001 GMT Tuesday) at Kennedy Space Centre in Florida.

"Welcome back to Earth after a fantastic flight," said Scott Altman at Mission Control.

The shuttle had been due to touch down at 1718 EST, but landing was delayed because of concerns about crosswinds on the runway.

After touchdown a Nasa spokesman said the crew were "very happy with the success of their mission".

Speaking for the crew, Swiss astronaut Claude Nicollier said: "These were probably the busiest but the most gratifying eight days of our lives."

A planned news conference with the crew was scrapped.

Instead, the seven crew members performed final technical checks and underwent medicals before being reunited with their families.

'Morale boost'

During the last 12 months, Nasa was able to launch only three space shuttle missions due to faulty wiring discovered in all four crafts.

1999 will also be remembered as the year Nasa lost two missions to Mars. The Mars Climate Orbiter is believed to have burned up in the planet's atmosphere in September. The Mars Polar Lander disappeared without trace or explanation earlier this month.

"To get up and flying again is a morale boost and the fact that the mission was successful was equally important," said Joseph Rosenberg, Nasa's associate administrator for space flight.

The success of the Discovery mission has also allowed Nasa administrator Dan Goldin to respond to criticism of Nasa's budget overspend, caused in part by repeated failed take-off attempts.

"This demonstrates once again that you cannot just send robots up there to fix the telescope," he said.

The newly-repaired Hubble telescope was released back into space by the shuttle on Sunday.

French astronaut Jean-Francois Clervoy used the shuttle's mechanical arm to gently lift the 12-tonne telescope from Discovery's cargo bay and send it into orbit.

During the mission, US astronauts John Grunsfeld and Steven Smith installed a new radio transmitter, data recorder and steel shields to protect Hubble's exterior.

Nasa had spent several years developing a computer able to withstand the radiation in space which degrades normal electronics.

Michael Foale and Claude Nicollier installed the new computer and replaced one of the telescope's large guidance sensors which point the $3bn Hubble precisely towards the phenomena it is observing.

Nasa's main observatory on the Universe has been out of commission since mid-November, when it shut itself down.

Scientists will test the telescope's instruments over the next two weeks in the hope of putting the telescope back into service on 9 January.

"We turned on all the instruments last night and they are all up and operating," said Franck Cepollina, a Hubble project manger.