"New Window on the Universe"

By Dick Thompson

Even on a clear night, astronomers cannot see forever. Light from the stars is diffused and distorted by the earth's atmosphere. To the casual stargazer, that produces a beautiful twinkle, but to the astronomer it is a tragic blur. Star watchers have long dreamed of somehow getting above the atmosphere to have an unobstructed look at the universe.

Now their opportunity has come. This week the space shuttle Discovery was scheduled to take off and deliver into earth orbit the Hubble space telescope, a bus-size instrument that will see the cosmos ten times as clearly as any ground-based telescope ever has. Scientists have impatiently awaited the historic launch through three years of delays caused by the shuttle's problems in the aftermath of the Challenger explosion.

Once aloft in the dark void of space, the Hubble promises a leap in astronomical observing power unlike anything since 1609, when Galileo first pointed a telescope at the heavens. As never before, astronomers have a realistic hope of seeing planets that orbit distant stars, watching tidal waves of energy swirl around black holes and spotting the birth of galaxies. The Hubble, says presidential science adviser D. Allan Bromley, "will open entirely new windows on the universe."

Named for Edwin Hubble, the great astronomer who discovered in the 1920s that the universe is expanding, the space telescope has a mirror 2.4 meters (7.9 ft.) in diameter that will focus light on an array of cameras and instruments. After recording and analyzing the radiation, the instruments will translate it into electronic impulses and beam it down to earth at a prodigious rate -- fast enough to fill a 30-volume encyclopedia in 42 minutes. Moreover, the Hubble will literally view the stars in a new light: the space observatory can see ultraviolet radiation that fails to reach ground telescopes because it is largely blocked by the earth's ozone shield.

Building the Hubble and putting it into space has cost the U.S. Government $1.5 billion, and that is only the beginning of the investment, which will likely top $5 billion. The telescope is being run by scientists at the new Space Telescope Science Institute, housed at Johns Hopkins University in Baltimore. The data will be collected by some 380 institute researchers and computer technicians and will be used by scientists all over the world. Over the Hubble's expected 15-year life-span, teams of astronauts will shuttle to and from the telescope to service and upgrade it.

The Government's Hubble budget alone will amount to an annual injection of more than $150 million into the scientific community. No wonder that researchers were awaiting the launch with both excitement and apprehension. "A lot is riding on that pillar of fire," observed institute director Riccardo Giacconi.

The Hubble will not make ground telescopes obsolete, since there is a limit to how many scientists can use it and how much light it can gather at one time. The huge new Keck Telescope, which is nearing completion atop Mauna Kea in Hawaii, will complement the space observatory. Privately developed by the University of California and Caltech and financed mainly by the W.M. Keck Foundation, the Keck has a dish 10 meters (32.8 ft.) in diameter. That is nearly twice the size of the next largest telescope, a problem-plagued 6-meter (19.7-ft.) dish in the Soviet Union. The Keck may not see the heavens as sharply as the Hubble, but the bigger, ground-based telescope can take in much more light in a short period of time. By combining high-quality images and a large quantity of data, the Hubble and the Keck will usher in a new era for astronomy.

One advantage of the Hubble is that it will offer the clearest pictures yet of the most distant objects in the universe. And the farther away those objects are, the longer the light has been traveling. So the Hubble is a spyglass that enables astronomers to look way back in time to earlier ages of the cosmos. Says institute astronomer Eric Chaisson: "The space telescope should allow us to see sufficiently far out into space and sufficiently back into time so that we can begin to probe the regions at which galaxies actually formed, and that's the greatest missing link in all of modern astrophysics."

The Hubble will also cast its sharp eye around stars in this galaxy, looking for traces of planets. So far, only dusty disks thought to be planetary precursors have been observed near some suns. "With the space telescope we have a fighting chance of seeing a planet," says European Space Agency physicist F. Duccio Maccheto.

Another mission will be to focus on planets around the sun and send back pictures as sharp as those from the Voyager spacecraft -- with one major difference. "On a flyby, you get one moment in time and look at whatever is looking at you," says institute planetary scientist Robert Brown. Hubble will allow astronomers to study planets over a long period. On Mars, for example, dust storms arise from small regions and eventually cover the entire planet. Now scientists will be able to follow that mysterious phenomenon.

Even with their powerful new tools, astronomers will not be satisfied. While upgrading the Hubble in the 1990s, NASA plans to ring the earth with satellite observatories that can receive and analyze infrared radiation, X rays and gamma rays. "It's as if we never could see at all at the beginning of the decade, and by the end we'll have 20/20 vision," says Princeton's John Bahcall, president-elect of the American Astronomical Society.

The ultimate observatory would be on the moon, a real possibility in the next century. Just as Edwin Hubble used the best instrument of the 1920s to discover that our galaxy was not the only one in the cosmos, perhaps a moon- based telescope would reveal startling regions of space -- and time -- never seen before.

With reporting by Michael D. Lemonick/New York