NASA to go ahead with risky Hubble telescope repair

GREENBELT, Md., Oct 31 (Reuters) NASA said today it would undertake a potentially risky shuttle mission to extend the life of the Hubble Space Telescope until at least 2013.

NASA Administrator Michael Griffin, speaking to cheering scientists who had feared Hubble's earlier demise, said a space shuttle would make one final maintenance trip, tentatively in 2008, to the orbiting telescope.

The trip will go ahead even though the shuttle astronauts would be unable to take shelter on the International Space Station if something went wrong, Griffin said in announcing the decision at the Goddard Space Flight Center near Washington.

Hubble is considered by some scientists to be the most important astronomical instrument ever. It seized the public's interest as it captured images of star birth and death, detected planets outside our solar system and snapped eye-catching visions of the Milky Way and other galaxies.

It has also examined the atmosphere of an extrasolar planet and helped determine the age of the universe.

Goddard Space Flight Center Director Ed Weiler said Hubble had fundamentally changed what scientists know about the universe. ''The universe doesn't read our textbooks,'' he said.

''It has this bad habit of not doing things we say it should.'' Scientists say that without repairs the 16-year-old orbital observatory would function for only two or three more years.

NASA had earlier planned a servicing call to the telescope -- the fifth since its launch in 1990 -- to install two new science instruments and replace spent batteries and faulty steering gyroscopes. It canceled that trip after the shuttle Columbia was destroyed as it returned to earth in 2003.

Safety upgrades put in place since then call for shuttle astronauts to stay aboard the International Space Station if they find their shuttle has been damaged. Crews heading to Hubble's orbit, however, cannot reach the station.

Griffin said a second shuttle would be ready to launch if a Hubble repair crew runs into trouble. There are no guarantees a rescue mission would work, however.

''We all as a nation know now that flying the shuttle carries more risk than we would like,'' Griffin said.

Shortly after it was launched on April 24, 1990 from space shuttle Discovery, Hubble was found to have a flaw in its main mirror that blurred its vision. Astronauts corrected the problem in a shuttle mission in 1993.

The final maintenance trip is tentatively set for May 2008.

Astronauts on the 11-day flight will take five separate space walks to add the new equipment.

''We're essentially going to get a new Hubble,'' said Maryland Democratic Sen. Barbara Mikulski, who fought to preserve the telescope when NASA decided to cut off support in 2004.

Cancellation of the Hubble servicing drew harsh public criticism and NASA later vowed to reconsider its decision.

Because the shuttle fleet will be retired in 2010, the Hubble mission will mean one less shuttle flight available to finish building the 0 billion space station, a project of the United States, Russia, Europe, Japan and Canada.

REUTERS SRS BD0035