The situation was comparable to having the power adapter for your laptop computer conk out, NASA scientists said at the press briefing.
Operations were suspended for all three detectors as the engineers sought the best way to fix the problem.
Meanwhile, astronomers who had hoped to be using the telescope had to have their work rescheduled.
"In any given week we may do one or two dozen observations" that had to be postponed, said Dave Leckrone, senior project scientist for the Hubble program.
But none of the lost observations involve critical "targets of opportunity" that won't be visible when the scientists get another chance, he added.
"Every observation lost because of the suspension will be rescheduled at a later date," Leckrone said.
In fact, he says, the switchover will give NASA a chance to improve the telescope's performance.
One of Hubble's sensors would produce even sharper data if its operating temperature were lowered by a few degrees.
But that would have required recalibrating the detectora project that is enough of a hassle that the change hadn't been made.
Now the instrument will have to be recalibrated anyway, so the engineering team has the opportunity to kill two birds with one stone.
"We're getting a little bonus," Leckrone said.
Controversy erupted in 2003, when the crash of the space shuttle Columbia brought the shuttle programand Hubble's regular maintenanceto an abrupt halt.
Hubble needs regular servicing missions, so grounding the shuttles put the telescope's future in jeopardy.
NASA reinitiated the shuttle program with the launch of Discovery last year, but a chunk of insulating foam just missed the craft's wing during liftoff, and the agency again grounded the fleet.
Analysts are keeping a close eye on Discovery's scheduled launch this weekend, which could prove whether the program is safe enough to continue (read "Discovery Mission Will Make or Break Shuttle's Future").
Meanwhile, the power-supply failure aboard Hubble raises questions about whether the telescope might need an additional shuttle-servicing mission.
Such a mission would be nice, if NASA's top officials decide to do it, says Jennifer Wiseman, a Hubble program scientist from NASA headquarters.
"But we've been working to allow [the Hubble Space Telescope] to operate in its current state for as long as possible," she said.
Hubble has had other problems over its lifetime that have been successfully fixed from the ground, the scientists point out.
The most notable of these was a glitch with the imaging spectrograph, which had to be switched to backup systems four years after it was installed in 1997.
That instrument continued to operate until 2004well exceeding its five-year design life.
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