WASHINGTON – F ifteen years after its launch on April 24, 1990, the Hubble Space Telescope is still churning out impressive science results. Hubble data have produced more than 4,000 peer-reviewed science papers to date, with a record 502 papers based on Hubble results published in 2003 alone. Not bad for a telescope that was denounced as a national disgrace because a design mistake skewed the spacecraft’s optics so that images had to be manipulated with complex software to be of any scientific value.

In December 1993, Space Shuttle Commander Richard Covey and his crew repaired Hubble’s blurred vision by installing new instruments. Space shuttles have flown to Hubble three times since to replace components and install new instruments. A final servicing mission had been planned for 2003, but the loss of the Space Shuttle Columbia in February that year put those plans on hold.

In January 2004, NASA Administrator Sean O’Keefe canceled the final servicing mission, touching off a political firestorm that led NASA to consider sending a robotic spacecraft to repair Hubble. NASA spent the better part of a year preparing the robotic servicing mission before announcing in February that it was requesting no money to continue the effort.

NASA’s new administrator, Mike Griffin, said during his Senate confirmation hearing April 12 that robotic servicing was still off the table, but that he would consider sending a space shuttle to Hubble. On April 18, during his first press conference as NASA’s new chief, Griffin said he would convene an internal review immediately following the next space shuttle launch “to weigh the pros and cons” of reinstating the canceled shuttle servicing mission. That launch is now scheduled to occur May 22.

Without servicing, Hubble is expected to last perhaps until mid-2008, when its gyroscopes are predicted to fail.