Once considered a screw-up of cosmic proportions, the Hubble Space Telescope has turned into the comeback kid of astronomy in the year since wrench-wielding astronauts fixed its blurred vision.
"The repair really has meant an unveiling of our eyes," said Duccio Macchetto, an astronomer with the Space Telescope Science Institute and European Space Agency. "We knew we could get there. We had tantalizing evidence before the repair mission. And now we are there. It's still like a new toy for Christmas. And we're all kids at heart."
In the past 12 months, Hubble snagged once-in-a-millennium pictures of comet fragments hitting Jupiter, refined measurements of the age of the universe and found solid evidence that a gargantuan black hole is slurping up stars in the middle of a nearby galaxy.
"The science has been coming so thick and fast that we barely have time to breathe and recollect what happened this year," said Hervey "Peter" Stockman, deputy director of the Space Telescope Science Institute in Baltimore.
In an 11-day flight that ended last Dec. 13, astronauts aboard the space shuttle Endeavour succeeded in snagging Hubble some 377 miles above the Earth. After installing 11 pieces of equipment during five spacewalks, they delicately placed the telescope back in orbit.
Among the most important repairs were optics installed to correct a flaw in the Hubble's 94.5-inch main mirror and new solar panels to eliminate an image-jarring jitter caused by the original panels.
The $628 million overhaul was probably NASA's most ambitious and difficult effort since the Apollo moon launches of the late 1960s and early 1970s. Contrary to what many scientists and the astronauts expected, all of the repairs were successful.
"We knew we would be able to accomplish some of the fixes," recalled Claude Nicollier of the Euro- pean Space Agency, one of the seven astronauts on the repair mission. "We never dreamed that we would be able to accomplish the whole recovery of the telescope."
Mr. Nicollier, who is Swiss, has crisscrossed Europe over the past year giving lectures about Hubble. Both the technically challenging repair flight and the telescope itself, he said, seem to have "captured the imagination of people."
"A lot of people, I have a feeling, have Hubble in their hearts," said the scientist, who is now working in Houston on robot systems to be used in building the planned international space station.
There haven't been any large anniversary parties at Baltimore's Space Telescope Science Institute.
Partly, institute scientists say, they are too busy processing, storing and analyzing the images and other data streaming down from the spacecraft. Partly, perhaps, the mood is less than joyous because of a 20 percent reduction in NASA funding over the past year that has forced the institute to reduce its work force from 420 to 350.
"There definitely was an effect on morale by the layoffs and reduction in funding," Dr. Stockman said. But there is still excitement about the increased flow of data from Hubble, and about planning for a mission to install more advanced instruments in Hubble, scheduled for 1997.
After the mirror flaw was discovered in 1990, NASA considered a limited 1993 repair flight. But Holland Ford, an astronomer at the Johns Hopkins University, helped lead an effort to nudge NASA to pursue a far more ambitious repair job. Dr. Ford and his fellow astronomers got what they wanted.
"We are vindicated," he said.
He recalled how, a few weeks after Hubble's launch, 15 years' worth of work on the instrument and $1.5 billion in tax dollars seemed to have been thrown away. "The range of emotions were disbelief to anger to despair," he said.
Soon after the repair, Dr. Ford and Richard Harms of the Landover-based Applied Research Corp., a high-technology company that provides scientific services to NASA, turned Hubble on the core of a nearby galaxy, known as M87. They found the strongest evidence so far for the existence of a black hole, an object so massive that nothing can escape its gravity, not even light.
Using Hubble's newly acquired acuity, Dr. Ford and his colleagues discovered that a gas cloud at the center of the galaxy is spinning at about 1.2 million mph. It would take a compact object with the mass of 2.4 billion suns, they calculated, to accelerate the gas to that speed.
Dr. Ford vividly remembers the meeting where he first saw the M87 black hole data. "When we went out of that room, we were not quite touching the floor. It was one of these once-in-a-lifetime events."
Hubble also stunned many scientists this year by uncovering evidence that the so-called Big Bang that created the universe occurred a mere 8 billion to 12 billion years ago -- when there are several stars in our own galaxy that seem to be at least 14 billion years old.
That puzzling finding will force astronomers to reconsider theories of how the Big Bang occurred, or how stars form.
K? With its corrective optics, Hubble also showed astronomers:
Close-ups of more than 21 fragments of the comet Shoemaker-Levy 9 slamming into Jupiter in July, splotching the surface of the gas giant. "That was something that happens once in a lifetime, probably, maybe once in a millennium," said Stephen P. Maran, senior staff scientist at NASA's Goddard Space Flight Center in Greenbelt. "We got Hubble working perfectly just in time to observe that. That would otherwise be an opportunity lost to humanity."
* A picture of two enormous rings of gas, dubbed "hula-hoops" by astronomers, floating in space near Supernova 1987A, a star that exploded seven years ago. Nothing like them has ever been seen before, and scientists can't explain them.
* The surprising discovery that the planet Neptune had lost its Great Dark Spot, first glimpsed by Voyager II in 1989. "On Jupiter, there's something similar -- the Great Red Spot," Dr. Maran said. "And that's been there for 300 years. This thing on Neptune is already gone."