The telescope that once needed eyeglasses but then gave scientists revolutionary insights into the cosmos is in trouble again.
On Monday, NASA is expected to present a budget to Congress that does not include any money to fix the aging Hubble space telescope. Unless Congress sets aside $1 billion or more for a robotic mission or commits to a space-shuttle trip to upgrade the telescope, it could stop sending its jaw-dropping pictures of the universe as soon as 2007.
Few scientists want Hubble to go away, but the budget prediction has reignited a simmering debate about how much should be spent to keep the telescope working. A new space telescope is scheduled to be launched in about six years and NASA's budget is tight as it starts to fulfill President Bush's mandate to send astronauts on exploratory missions to the moon, and beyond.
Hubble supporters, however, say contributions the telescope has made -- and can still make -- to science and public understanding of the heavens is worth the cost.
''[Hubble] has advanced the field more than any telescope since Galileo's," said Harvard astronomer Robert Kirshner, who uses the telescope to study dark energy, a little-understood force believed to be speeding up the expansion rate of the universe.
''This is important to astronomers, but it is also important to a lot of people in this country, young and old, who are interested in learning more about what the universe is and how it works," he stated in an e-mail interview.
So far, NASA officials have remained quiet about the White House-ordered funding plans for this year, first reported by the trade newspaper Space News and its affiliated publication, Space.com. But the newest controversy follows a yearlong tug of war between scientists and outgoing NASA administrator Sean O'Keefe over Hubble's fate.
In January 2004, O'Keefe abruptly canceled a fifth space-shuttle-servicing mission that would have extended Hubble's life by adding new batteries and gyroscopes. His announcement was delivered a year after the shuttle Columbia blew up, killing all seven astronauts aboard and opening up NASA to scathing criticism over safety.
It also occurred two days after Bush called for NASA to refocus efforts on exploratory manned space travel as the way to drive new scientific innovation and ''extend a human presence across our solar system." While Bush said he would work toward increasing NASA's budget, much of the money for the new effort would be found by changing the priorities regarding NASA's spending.
O'Keefe's announcement sparked an outpouring from ''Hubble huggers" -- both scientists and members of the public who view the telescope as a cultural icon.
Hubble first captured the public imagination when a flawed mirror caused it to take blurry pictures. But, after a space-shuttle mission installed an instrument to correct the flaw and it started sending back eye-popping pictures, people fell in love with it.
After O'Keefe's announcement, a website sprang up asking for donations to publicly pay for the telescope's repair. Scientists delivered eloquent missives about its contributions to our understanding of the evolution of galaxies and the age of the cosmos. Months later, O'Keefe -- still anxious about sending a space-shuttle crew to repair the telescope -- announced that NASA would pursue a robotic mission instead.
Controversy erupted again. Some saw a robotic mission as far too expensive and too risky. A National Research Council panel of experts and the American Astronomical Society agreed: Hubble should be fixed but a space-shuttle team was needed.
If NASA's new budget matches Space.com's projections, however, there will be enough money only to drop Hubble safely to Earth.
''This is going to become a very beautiful fight," said Phil Plait, an astronomer at Sonoma State University in California. ''Hubble has changed the way the public sees astronomy. When I give out pictures from Hubble, they are snapped up. . . . [The pictures] are art. [People] don't want to see something so beautiful dropped into the Pacific. It's like kicking a puppy."
Hubble, the first space-based optical telescope, is one of NASA's greatest success stories. Its discoveries have been the basis of more than 3,500 scientific papers. Its ability to detect faint supernovae contributed to the discovery that the rate of the universe's expansion is accelerating. It showed researchers that massive black holes sit in the center of most galaxies. At the same time, it wooed a new generation of space enthusiasts with spectacular pictures of an expansive, vibrant universe with stellar nurseries, dying stars and colliding galaxies.
Hubble is on the threshold, Kirshner and other scientists said, of discovering even more about dark energy's role as a kind of antigravity force, possibly answering one of the great mysteries of physics. Already, gains are being made in measuring dark energy's strength and permanence in the universe, astronomers said.
Meanwhile, the space telescope is also studying far-off planets and stars to help understand the universe's origins. Every year, Hubble's administrators receive more than 1,000 research requests to use the telescope: Only about one in seven are granted.
While scientists are eager for the powerful James Webb telescope to come on line in 2011, they say it only complements -- not replaces -- Hubble, which will continue to be better at seeing ultraviolet light and detecting phenomena such as black holes and quasars.
''The thing about Hubble is not only is it the best thing we have up there in terms of astrophysics, but it is working," said John Clarke, a professor of astronomy at Boston University who uses Hubble to study auroras around Jupiter and Saturn. Astronomers are poised to build on Hubble's earlier work, he said, and he worries the Webb, like many missions before it, could be delayed for years, leaving scientists without new information coming in.
Still, other researchers say NASA -- financially squeezed to fulfill Bush's promise -- needs to make some hard decisions. Maybe it is time, they say, to let Hubble go. And it may not make sense to work on Hubble when the Webb will be operating soon.
''It's unfortunate that Hubble will apparently not be repaired," said Eric Chaisson, director of the H. Dudley Wright Center for Innovative Science Education at Tufts University who wrote a book about Hubble. In an e-mail, Chaisson stated: ''If NASA is to move forward to fund and build a better, more robust space telescope -- the Webb Telescope -- then astronomers need to accept that it probably is time to let Hubble run its course, as best it can, over the next few years, without incurring vast additional sums to fix it further."
And perhaps, some scientists speculate, the budget battle is really about politics. Mindful of the telescope's enormous public popularity, perhaps NASA put it on the chopping block, expecting new money to be added later.
''I am hopeful, but it is discouraging we have to go through this exercise. . . . We certainly hope Congress does not let it be treated in this manner," said Rodger Thompson, a University of Arizona astronomer and principal investigator of Hubble's infrared camera and spectrometer. ''Hubble has shown us we are part of a universe. It has expanded people's minds."
Beth Daley can be reached firstname.lastname@example.org.