Hubble's promise

Space telescope's impact may rival work of Galileo

THE HUBBLE Space Telescope is a little like a Nobel Peace Prize winner or basketball superstar Michael Jordan. It commands a unique respect.

NASA's long-awaited super telescope is a $1.5 billion marvel of precision and high-tech - a first cousin to the super-secret spy satellites that can read a license plate from hundreds of miles in space.

But, pointed toward the vastness of space rather than the Earth, the 43-foot-long Hubble promises to function like a wondrous time machine.

"When Hubble lifts off, we will witness not just another launch but rather a turning point in humankind's perception of itself and its place in the universe," says Lennard Fisk, NASA's associate administrator for space science.

First scheduled for launch in late 1983, the Hubble and a crew of five veteran astronauts inside the space shuttle are scheduled to lift off from NASA's Kennedy Space Center at 7:47 a.m. CDT Tuesday, the opening of a 2 1/2-hour launch period.

On the day after launch, orbiting high above the grime and distortion of the earth's atmosphere, the shuttle fliers will carefully raise the 25,000-pound telescope from the shuttle's cargo bay and release it on its 15-year mission.

The telescope is designed to peer 10 billion light years distant, sneaking up on the first radiance that raced from the Big Bang, the tremendous explosion theorists believe created the universe. It will transmit images back to teams of astronomers over a network of ground stations and satellites.

"If you ask the proverbial man on the street to name a space science mission, the first one to come to mind is Hubble," said Fisk. "In fact it may be the only one to come to mind.' The Hubble's discoveries promise to rank second only to those man himself might uncover if human explorers were along for the visual journey to the far reaches of the universe.

"We think the really exciting things will be those we have no idea about," says California Institute of Technology astronomer James Westphal.

Modern astronomers compare Hubble's launch in significance to the moment 17th century Italian physicist Galileo Galilei raised a crude telescope to the night skies.

"When Galileo first looked with his little telescope, no one knew that the moon had craters on it," noted Westphal. "No one knew that Jupiter had bands across it, a red spot or little moons that circled around it.' Nor that the universe is so immense that it holds millions of galaxies like our Milky Way, let alone celestial enigmas like super novas, black holes and pulsars.

The Hubble, the most expensive unmanned spacecraft every constructed by NASA, is the flag ship of a quartet of orbiting instruments that NASA calls the Great Observatories. Each is intended to explore a specific but complementary region of the electromagnetic spectrum.

The space telescope is best known of the quartet because it will tackle observations in the visible light region of the spectrum, while the Gamma Ray Observatory, the Advanced X-Ray Astrophysics Facility and the Space Infrared Telescope Facility will conduct their detective work in unseen regions.

The Gamma Ray Observatory is scheduled for launch in November. The AXAF and SIRTF are still under development but slated for launch by the turn of the century.

The Hubble is designed to be re-visited by space shuttle crews once every three years for maintenance, reboosting and modifications that include placing powerful new observing instruments aboard. The telescope will cost $200 million annually to operate.

Most of the telescope's first eight months in orbit will be devoted to "checking out" its mechanical systems and calibrating its powerful scientific instruments.

Nonetheless, the space agency plans to christen the Hubble about two weeks after launch with a traditional "first light"ceremony to demonstrate the telescope's powers. It promises to be a spectacular sample of photographs of the cosmos.

As stunning as Hubble's unanticipated discoveries might be, the international collection of astronomers who will use the telescope have tailored a complex schedule of observations intended to provide a deeper understanding of the celestial mysteries and partial theories that already confront them.

Among them: Attempts to nail down the existence of black holes - super-dense objects that astrophysicists believe are dead stars that super novaed, or exploded, then collapsed.

The term black hole is derived from the intense gravitational force associated with them. So strong is the force then even light cannot escape.

One target of the black hole search will be M87, a galaxy 35 million light years away in the constellation Virgo. What has captured the interest of astronomers is a jet of material emerging from the center of M87.

The jet suggests the presence of a massive, spinning black hole, theorists say. The rotation creates an electrical field with field lines that serve as paths for some of the material being sucked toward the black hole to be flung off in a jet.

Using the Hubble's ultraviolet instruments, observers hope to "peel away" all of the interference that astronomers believe obscures M87's hot nucleus.

Astronomers also are hopeful that Hubble will permit them to spot proof that planets circle any of 80 nearby stars.

One candidate, Beta Pictoris, is a "mere" 50 light-years from Earth.

So far, astronomers have detected rings of lose matter circling a few of those stars and believe the material is in the process of accreting into planets.

But even with Hubble's resolving powers, scientists say an observable planet would have to be at least the size of Jupiter, the largest in our solar system.

Astronomers also will use the space telescope to make regular observations of the outer planets of our own solar system.

So far, their most spectacular views of Jupiter, Saturn, Uranus and Neptune were provided by NASA's two Voyager probes during brief "flybys" of the four large planets.

Launched in 1977, it took the Voyager probes a dozen years to complete their Grand Tour. Voyager 2 sailed past Neptune last August.

The space agency believes it can regularly obtain photographs of similar quality using Hubble, allowing it to monitor changes in the swirling Red Spot that dominates the surface of Jupiter or in the volcanic activity on its moon Io.

The remarkable engineering that produced the Hubble is nearly as spectacular as the space telescope's mission.

Proposals for a space-borne telescope first emerged in the writings of German rocket engineer Hermann Oberth in the 1920s and Princeton University astronomer Lyman Spitzer in the 1940s.

Yet, it wasn't until 1977 that Congress approved funding for the telescope program, which by then had picked up the European Space Agency as a participant.

As it neared completion in 1983, the telescope was renamed for American astronomer Edwin Hubble.

A half century earlier, Hubble described the expansion of the universe, providing the foundation for the Big Bang theory.

NASA selected the Lockheed Missiles and Space Co. of Sunnyvale, Calif., to build the actual spacecraft and the Perkins-Elmer Corp., of Danbury, Conn., since purchased and renamed the Hughes Danbury Optical Systems, Inc., to craft the telescope's highly polished 94 1/2-inch relecting mirror.

So smooth is the mirror's surface that no part of it deviates from any other part by more than one millionth of an inch. If scaled to the size of the Earth's surface, the tallest blemish would rise no more than five inches above the surface.

The Hubble, if stationed in Los Angeles, could spot a 6-foot tall astronaut standing by the shuttle launch pad more than 2,000 miles away in Florida, or the glow from a flashlight 250,000 miles away on the surface of the moon. It is a half billion times more sensitive than the human eye.

In spite of its fantastic capabilities, the space telescope has its limitations.

At an altitude of 380 miles it will circle high above the distortions imposed by the Earth's atmosphere.

But, it still will be close enough to its home planet that the mass of the Earth, combined with the damaging glare of the sun, will restrict its viewing time to just 35 percent, or 8 hours, each day.

"That is a little better, maybe a lot better than the average ground-based telescope, where you have daylight for 12 hours a day and clouds," said Ed Weiler, NASA's chief program scientist.

The viewing efficiency could be improved to 80 percent or more if the Hubble was launched to a much higher altitude, but at such a distance it could not be reached by the space shuttle for maintenance.

"I wouldn't want to put this up where I couldn't get to it and have some little part break that might only cost $100," said Weiler.

Working around the clock, 300 ground personnel will operate the Hubble from the Space Telescope Operations Control Center at NASA's Goddard Space Flight Center in Greenbelt, Md.

The many astronomers who use the observatory will do so through the Space Telescope Science Institute at Johns Hopkins University in nearby Baltimore. The institute is governed collectively by the many universities and research institutions that will use the space telescope, rather than by NASA.

Nearly 400 personnel will staff the Johns Hopkins facility around the clock.