The proposed 4-meter space telescope would reuse or replicate much of the "Star Wars" hardware developed for the so-called Advanced Large Optics Technologies (ALOT) telescope, visible here in a testing chamber at Itek Optical Systems. ALOT's 4-meter, segmented mirror would, however, be replaced by a monolithic, meniscus mirror of equal size developed as the central, annular segment of another "Star Wars" mirror program, Itek's 11-meter Large Optical Segment project.

Photo: Itek.

The recent images of stars forming on the tips of huge columns of interstellar gas and dust are just the latest in a string of spectacular discoveries made by the Hubble Space Telescope. The orbiting telescope has discovered new satellites around Saturn, has challenged cosmological orthodoxy by hinting that the universe may be younger than its oldest stars, and has otherwise amazed astronomers and the public alike. Despite its early problems, Hubble's performance has amply vindicated the idea of locating telescopes in space.

But Hubble also has been very expensive -- costing more than a billion dollars to build and some $250 million a year to operate. If the space sciences are not to slip into a decline matching NASA's dwindling budget, researchers must find new and innovative ways to perform space missions.

Unfortunately, NASA's "smaller, faster, cheaper" approach is limited where certain spacecraft systems are constrained by the laws of physics and cannot be miniaturized. To collect the feeble light from distant objects, for example, space telescopes must contain very large mirrors.

In the 15 years since Hubble was built, scientists and engineers have made enormous advances in optical technology. Future space telescopes could be much larger and much cheaper to build and operate than Hubble. The use of very thin mirrors, for example, could significantly reduce the mass of the spacecraft, resulting in major cost savings. Placing future telescopes in higher orbits also could dramatically increase available observing time and greatly simplify operations _ a major contributor to Hubble's high costs.

The problem is that each of these new concepts is risky. And neither NASA nor the astronomy community can afford another expensive and embarrassing failure like the spherical aberration built into Hubble's main mirror. Before they rush to embrace these new technologies, space scientists must have confidence that the technologies will work as advertised. Unfortunately, current budgets leave little room for missions devoted to demonstrating and validating new technologies.

But there is another way. With the relaxation of tensions among the superpowers, military technologies that were once secret are now available for civilian use. A recent study by the National Research Council (NRC) points out that some of this hardware could provide an answer to space astronomy's dilemma.

During the Cold War, the federal Ballistic Missile Defense Organization actively sponsored the development of spacebased laser weapons. As part of this program, more than $100 million was invested in developing the optics for an ultralightweight, 4-meter space telescope. Although the project was canceled, many of the telescope's components were constructed and are now available for civilian use.

The team of astronomers and optical experts convened by the NRC to analyze the Star Wars hardware found it capable of performing astronomy programs not possible with Hubble or any other facility in existence or in development. For example, astronomers could study the warm material at the edge of the universe that is just forming into galaxies. They could probe the many small bodies at the edges of our solar system to identify the source of comets.

In fact, putting Star Wars technologies to work will move spacebased astronomy in exactly the directions needed to undertake some of its most challenging missions. Astronomers could detect and characterize planets around other stars or study the earliest objects in the universe. And these technologies would be extremely cost effective, entailing expenditures in the hundreds of millions rather than billions of dollars.

Today much of the relevant hardware is gathering dust in warehouses and testing chambers. Yet this legacy of the Cold War could be crucial to NASA's ability to carry out major space astronomy missions. Astronomers need to become directly involved in the continued study, development, and eventual flight testing of this hardware. They also may find that these technologies have scientific applications beyond those already considered.

The Cold War may be over, but the need for advanced technologies is becoming greater all the time. We need to look carefully at devices developed for war and ask how they can be used in peace.

(Michael A'Hearn, professor of astronomy at the University of Maryland, recently chaired a task group for the NRC that examined astronomical technologies produced by the Ballistic Missile Defense Organization. David H. Smith was the task group's study director.)

The NRC report referred to, A Scientific Assessment of a New Technology Orbital Telescope, is available from the Space Studies Board, HA-584, National Research Council, 2101 Constitution Ave. NW, Washington DC 20418.