THE latest mission of the space shuttle Columbia was conceived as a unique approach to advancing scientists' understanding of the cosmos, particularly the hot, violent events that send out radiations invisible to the naked eye. The shuttle's much-troubled mission was saved from technical failure after quick improvisation by ground crews.
But the success was qualified. Due to land early this morning, it was brought back one day short of the planned 10 days and observed only 140 of its 250 targets.
The $150 million payload is also considered by some experts to be a prime example of how relatively small projects like it are often squeezed out by the big-ticket items favored by the National Aeronautics and Space Administration. By coincidence, a White House panel charged with charting the agency's future yesterday released a report criticizing NASA for its dependence on the shuttle and for pursuing grandiose big-budget projects at the expense of smaller ventures like Columbia's space telescopes that nevertheless promise big scientific returns.
The goal of Columbia's astronomy mission was to tackle fundamental riddles of modern astronomy, including what powers quasars, the most enigmatic and luminous objects in the sky.
During a mission plagued by the malfunction or breakdown of much support equipment, Columbia's seven astronauts wrestled with four relatively small telescopes in the shuttle's 60-foot bay. The automatic control of the three ultraviolet telescopes malfunctioned from the start, and manual control was lost after a computer failed. But steps resourcefully improvised on the ground enabled the astronauts to regain control of the telescopes. They succeeded in observing extraordinarily faint radiations from distant stars and mysterious objects, including glints of ultraviolet light and X-rays telling of cataclysmic events far away. Since radiations like these cannot penetrate the atmosphere, Columbia's high-flying observatory afforded astronomers a unique view of the universe.
Moreover, the mission was a first by virtue of observing an unusually broad range of frequencies. As one X-ray and three ultraviolet telescopes examined a heavenly target, astronomers on the ground in such places as Pennsylvania, Wisconsin, Australia and South America made simultaneous readings in the visible part of the electromagnetic spectrum. Never before have stars been subject to simultaneous scrutiny over such a wide swath of the electromagnetic spectrum, from X-rays to visible light.
"The simultaneity is important," said Dr. France A. Cordova, head of astronomy and astrophysics at Pennsylvania State University, whose department aided the observations. "Some incorrect assumptions have been made by studying separate bits of the electromagnetic spectrum." Plans Dim Accomplishments
But the achievements of Columbia's mission are less satisfactory when seen in the context of astronomers' original plans for the payload, known as Astro-1. The Astro's most serious problem, scientists say, is not its conspicuous vulnerability to technical upsets aboard the space shuttle but the fact that the Columbia mission is its only flight. The Astro telescopes will now be mothballed indefinitely because NASA has budgeted no more money for it. But the original schedule called for up to six flights of the same multi-telescope observatory, to be known as Astro-2, Astro-3, and so forth. The reduction is especially painful, scientists say, given the string of technical failures that plagued the one and only mission and compromised its ambitious goals.