DENVER — The Hubble Space Telescope, which once appeared doomed, could be rescued by robots, NASA's chief said Tuesday at a major astronomy meeting.

NASA administrator Sean O'Keefe said the space agency had just put out a request for proposals for robots to repair the 14-year-old telescope.

The audience of about 1,000 astronomers erupted into applause. The American Astronomical Society, which is hosting the meeting, has lobbied to keep the Hubble telescope operating.

NASA estimates Hubble will stop making observations by 2007 or 2008, when the batteries are expected to fail.

Spacewalking astronauts were supposed to install new batteries and other gear in 2006, but that shuttle mission was canceled by O'Keefe in January because of safety concerns after the loss of seven astronauts in the Columbia space shuttle accident last year.

O'Keefe had opened the door to ideas for robotic repair missions, but NASA's request for proposals involving robots is a bigger step toward that option.