Hubble goes blind, for now.

ASA's flagship observatory, the Hubble Space Telescope, has shut down for what astronomers hope will be just a short intermission. However, delays in scheduling a repair mission combined with a looming Y2K problem, could turn a brief break into a lengthy interlude.

Since January, Hubble has operated with only three of its original six gyroscopes active, the minimum to accurately point the observatory. That precarious situation prompted NASA last March to propose a repair mission scheduled for October. Several delays, due to wiring problems on the space shuttle, have now forced the 9-day mission to be rescheduled for Dec. 9. On Nov. 13, however, a fourth gyroscope failed, leaving the telescope unable to make observations.

To avoid any Y2K computer glitches, NASA won't fly the mission this year if electrical problems or bad weather postpones liftoff past Dec. 18, says Denny Holt, manager for the repair mission at NASA's Johnson Space Center in Houston.

The team plans to rely on the same flight software that guided the Hubble servicing mission in 1997 (SN: 11/6/99, p. 294). Although ongoing tests of the software haven't found any showstoppers so far, it has not yet been certified as Y2K compliant, Holt notes.

If the software needs only minor adjustments to make it Y2K compatible, the mission could fly as early as Jan. 13, he adds. But if the software has to be replaced, the launch could be delayed by an additional 4 months, which would waste more than $80 million.