When Halley's Comet blazes through our solar system five years from now, a number of countries will have launched space probes to meet it. Conspicuous by its expected absence, however, will be the country that has led the world in probing outer space -- the United States.
Although a Halley's mission would not have to be launched until 1985, preparation for the project has to begin by this fall, say Jet Propulsion Laboratory (JPL) scientists who have done preliminary mission planning. Unless approximately $25 million is committed to the project within the next few months , they say, the US will be grounded for what is considered to be one of the solar system's major events this century.
"The irony is that we've always led the world in the first great explorations of objects in our solar neighborhood," says Dr. Bruce Murray, director of JPL. "We were the first to go to another planet, the first to see Mars, Mercury, and Venus. That's been our tradition."
"And we have the technology to do it far better than anyone else," he adds, "so it's doubly ironic."
Scientists know very little about comets, which are believed to be icy snowballs of dust, ice, and gas. Born with the sun and planets some 4.5 billion years ago, comets are believed to have remained relatively unchanged since that time -- and so offer scientists a tantalizing opportunity to discover possible clues about the origin and development of the solar system.
Halley's comet, which first was spotted in 87 BC and swings through the solar system once every 76 years, is particularly alluring because it is the bestknown active comet and has an orbit predictable enough to be intercepted by spacecraft.
Already, the European Space Agency (ESA) -- a consortium of 12 nations -- has begun its own Halley's mission, as have the Soviets (with French participation). The Japanese will be making their first deep space probe with their Halley's project.
These missions, however, are not so sophisticated as that which the more-experienced US could launch. It is estimated, for example, that there is a 50 percent chance the ESA craft will fly on the dark side of the comet, which would make picture-taking impossible. The Japanese mission, which will carry no cameras, has an aiming accuracy of plus or minus 60,000 miles -- which could mean missing the comet by a long shot. The US, on the other hand, initially planned to launch a spacecraft that would rendezvous with the comet and fly side-by-side with it for several months.
But the US, it appears, may be sitting out this round of space exploration. Some critics blame the current situation on the Carter administration, which refused to fund any new space projects proposed by the National Aeronautics and Space Administration. Others say NASA was too preoccupied with the delayridden space shuttle to push hard for a Halley's project.
As a result, JPL, which oversees NASA's planetary probes, has had to abandon its ambitious plans. Scientists, however, are still holding out some hope for a smaller-scale mission. This project, with a price tag of $350 million, would fly through the comet's cloud -- within 400 to 600 miles of the nucleus -- and would produce more than 8,000 photographs, yielding humanity's first glimpes of the heart of a comet.
Most space launches require a five-to-six- year lead time. But because JPL scientists have pulled together a project that uses "off the shelf" equipment already developed for the Viking, Voyager, and upcoming Galileo launches, a Halley's mission still could be launched -- but only, they say, if it gets under way this fall.
For that to happen, NASA would have to reprogram an estimated $25 million in its fiscal 1982 budget of approximately $6 billion, which currently includes no money for the Halley's project. Such a move would require congressional approval -- and, JPL scientists say, an indication from President Reagan that he will approve funds for the project over the next five years. Whether that will happen -- particularly during a period of program cutbacks -- appears to be anybody's guess, say scientists. But they note that the five-year Halley's mission represents less than 1 percent of NASA's annual budget. And they point to a groundswell of media and public interest in the program.
"Our intercept mission is a special kind of opportunity for major scientific exploration," argues Dr. Murray. "It could be comparable with our first look at Mars. We know so little about comets that, by any country's standards, it's a must.
"It's terribly wrong that a country of these achievements should sit on its hands and be a spectator for what has to be one of the most exciting events of the 20th century," he continued. "The effect that has on our self-image is bad. It says, 'Hey, we're no longer trying to aspire to being No. 1'"