Getting A Handle On The Hubble Although Badly In Need Of Repairs, The $2 Billion Orbiting Observatory Is Providing Researchers Here And Elsewhere With Galaxies Of Information

October 20, 1991|By Douglas Birch

DOUG DUNCAN HAS A PROBLEM.

Normally, Dr. Duncan delights in problems. He thrives on questions, conundrums, quibbles, enigmas and perturbations.

Not just your average problems, like programming a VCR or tuning a car. No, Dr. Duncan is a professional astronomer, and astronomers love to tackle big problems. Huge problems. Problems like what stars are made of, how they are born and die and where they come from.

Today, the lanky and generally upbeat Dr. Duncan sits in his air-conditioned office at Baltimore's Space Telescope Science Institute and enjoys an uninterrupted view of the forest canopy ,, over Wyman Park dell, with a myriad of leaves shimmering in the heat. But his view of the cosmos, provided by the National Aeronautics and Space Administration's Hubble Space Telescope, is more problematic.

Dr. Duncan isn't worried about the Hubble's famous mirror flaw. That's old news. He has just spent 12 hours the day before, Labor Day, coping with one of a half-dozen other technical bugs that have cropped up in the $2.1 billion instrument since it was launched in April 1990.

An intermittent stutter in a power supply system keeps interrupting the transmittal of data from a machine aboard Hubble. The stutter has stalled Doug Duncan's careful measurement of a particular element in some of the Milky Way's oldest stars. Preliminary data has raised some intriguing questions about the moment the universe began. But at the time Dr. Duncan wasn't sure he'd get a shot at going back and verifying his earlier observations.

The story of tantalizing results and interrupted science is a familiar one at the space telescope institute, the center for Hubble research located on the Homewood campus of the Johns Hopkins University.

"What's especially frustrating is that the amount of data coming in with the spectrograph seemed, until just recently, very, very high," he says.

FOR A WHILE THE HUBBLE Space Telescope became a staple of stand-up comics and newspaper humorists, its name synonymous with snafus and screw-ups. The instrument seemed designed to explore the limits of Murphy's Law, not Einstein's theories of curved space and relative time.

First proposed in 1946, the orbiting observatory was supposed to do big science: produce laser-sharp pictures of faint objects near the edges of the universe for clues about its age and size. It was supposed to scan nearby stars for dim evidence of planetary systems. There was hope it would discover exotic new animals in the stellar zoo.

And Hubble was supposed to help solve the riddle of the ultimate fate of the universe. Will the stars all eventually burn out and disperse into a cold cosmic mist? Or at some time far in the future will all the matter in the cosmos be drawn together and born again in an unimaginable fireball?

But the telescope can't do much of the headline-grabbing work it was designed for. Because of a tiny flaw discovered in its nearly 8-foot main mirror shortly after launch, Hubble scatters all but a fraction of the light coming from an object. This flaw, called a "spherical aberration," means the Hubble can't see faint stars or galaxies any better than ground-based telescopes. And new technical problems -- less spectacular but still hobbling -- seem to pop up every two months.

National Aeronautics and Space Administration engineers worked hard on jerry-rigged fixes, using computers, for example, to clean up the fuzzy images from the flawed mirror. The 380 astronomers and staff at the telescope institute hunched over their computer terminals, figuring out new ways to do part of almost all the previously planned research projects. Today, the Hubble is chugging along, badly in need of repairs but still able to do workaday science. And, most scientists say, the observatory does it very well indeed.

THE DAY BEFORE THE AU- gust deadline for applications to use Hubble next year, overnight delivery firm trucks began pulling up in front of the institute on San Martin Drive, and drivers unloaded shopping carts filled with star-gazing proposals. Telescope institute officials received five times the number of requests to use the instrument than they could grant.

F. Duccio Macchetto, principal investigator for the Hubble's Faint Object Camera, says each of the camera's research programs "was affected in some way" by the mirror flaw. "We are limited to objects that are six to 10 times brighter than we would have liked them to be," he says. An observation program that was supposed to include a survey of a dozen stars, he says, might have been forced to skip the three or four faintest ones.

But most astronomers hoping to use the camera found a way to do part of what they planned. Of scores of programs, he says, only one was canceled outright: the search for evidence of planets around nearby stars.

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