CAPE CANAVERAL, Fla. (AP) – NASA will send a space shuttle to repair the 16-year-old Hubble Space Telescope, agency Administrator Michael Griffin announced Tuesday, reversing his predecessor’s decision to nix the mission.

Mr. Griffin’s announcement was greeted eagerly by astronomers who feared Hubble would deteriorate before the end of the decade without new sensors and replacements for its aging batteries.

The rehab mission, likely launching in May 2008 using space shuttle Discovery, would keep Hubble working until about 2013. Its estimate cost is $900 million.

The Hubble telescope has captured some of the most spectacular images of the universe, popularizing astronomy while at the same time advancing our understanding of space.

It has enabled direct observation of the universe as it was 12 billion years ago, discovered black holes at the center of many galaxies, provided measurements that helped establish the size and age of the universe and offered evidence that the expansion of the universe is accelerating.

“The Hubble telescope has been the greatest telescope since Galileo invented the first one,” said Senator Mikulski a fierce champion of Hubble, which is operated out of Maryland. “It has gone to look at places in the universe that we didn’t know existed before.”

The repair mission crew will include three veterans of the last Hubble mission, in 2002, and four astronauts on their first space trip, Mr. Griffin said.

Former NASA Administrator Sean O’Keefe had canceled a Hubble repair mission in the wake of the Columbia shuttle disaster that killed seven astronauts in 2003. Mr. O’Keefe believed the risks were too great and the remaining shuttle missions should focus on completing construction of the international space station.

Mr. Griffin, however, said Tuesday that he was convinced the Hubble mission could be conducted after the last three shuttle flights demonstrated astronauts’ ability to inspect the spacecraft in-flight and make repairs, even in hard-to-reach places.

“The safety of our crew conducting this mission will be as much as we can possibly do,” Mr. Griffin said. “We’re not going to risk a crew in order to do a Hubble mission.”

Unlike the remaining 14 shuttle flights needed to finish space station construction, astronauts going to Hubble wouldn’t have a refuge in the event of a catastrophic problem like the one that doomed Columbia. NASA would have another shuttle on the launch pad, ready to make an emergency rescue trip in case of trouble.

The Hubble mission would add two new camera instruments to the telescope, upgrade aging batteries and stabilizing equipment, add new guidance sensors and repair a light-separating spectrograph. Griffin named the crew members as veterans Scott Altman, John Grunsfeld and Michael Massimino, and rookies Greg Johnson, Andrew Feustel, Mike Good and Megan McArthur.

Hubble was launched in 1990 with a faulty primary mirror that prevented it from focusing, and it quickly became the butt of jokes. Three years later, astronauts Endeavour fixed the telescope’s blurred vision in the first of four repair trips.

“The Hubble has been a roller coaster,” said NASA Goddard Space Flight Center director Ed Weiler, Hubble’s chief scientist from 1979 to 1998. “It really has.”