Voyager II: swan song for US probes to the planets?

The Last Picture Show: that's how many of the Voyager team here view the 16, 000-odd pictures and the tremendous quantity of scientific data returned from Saturn last week.

As the national press corps packed up, the mood of the scientists and engineers who have worked closely and intensely for the past four years was bittersweet.

The sweetness stems from the fact that the spacecraft survived its encounter with the distant planet and achieved 200 percent of its scientific objectives, as project scientist Edward Stone of the California Institute of Technology puts it.

The bitterness has several roots. One is a natural sense of letdown after a period of suspense and intense activity. Another is fact that the problems the spacecraft experienced during the flyby -- its camera platform sticking -- reminded the Voyager team that there is a real chance the automated craft will not survive to Uranus, five years and more than a billion miles distant. But most acutely, the mood of depression comes from the feeling that, after two decades of spectacular successes, America's planetary exploration program is on its last legs.

"I've been thinking of buying a bar in Hawaii," morosely gibes Bradford A. Smith of the University of Arizona, the leader of the team of scientists studying the Voyager television pictures.

The unmanned planetary program -- which has pulled off such coups as landing the first spacecraft on the surface of another planet (the Viking Mars probes), putting the first orbiters around neighbor planets Venus and Mars, and giving mankind the first close look at the giant gas planets Jupiter and Saturn -- has been squeezed unmercifully between the budgetary constraints Congress has kept on the National Aeronautic and Space Administration (NASA) since the Apollo program and the substantial costs required to develop the space shuttle.

As a result, the budget of NASA's Office of Space Science has been dropping steadily since 1964 and now is 50 percent less than the 1964 level when adjusted for inflation. Planetary missions currently make up only 5 percent of the space agency's budget.

"We've had to fight . . . just to keep what we've had," says one NASA official, explaining the situation under the previous administration. Under President Reagan, NASA's budget has been cut by 10 percent overall, while the planetary program has suffered a reduction of more than 20 percent.

"The point is, there is some minimum level below which the planetary program is no longer viable," says one space scientist, adding that they are about at the level now.

Voyager researcher Richard Terrile, who works at the Jet Propulsion Laboratory (JPL) here, points out that the situation is more critical for the engineers who design and build spacecraft and the experts who fly them than for the scientists.

"Scientists can continue to study the data which has been accumulated in past missions but engineers need spacecraft to build and mission experts need spacecraft to fly," he explains. Without this, the experienced cadre that has made the US No. 1 in planetary exploration will be disbanded.

"It's a question of whether we want to be the leaders in space exploration," says JPL director Bruce Murray.

The Soviets, the European Economic Community, and the Japanese are supporting planetary missions strongly.If the administration cuts back much more, the US could loose its lead in this arena, a number of planetary researchers warn.

Currently, NASA has three major programs approved: the orbiting Space Telescope, a new mission to Jupiter, and a radar surface-mapping mission to Venus. But, given the current budgetary mentality in Washington, D.C., planetary scientists and engineers say they feel that some or all of these programs might be sacrificed in the name of the current budget emergency or if shuttle development costs more than estimated.

"I think it's significant that President Reagan or Vice-President Bush did not call to congratulate us or that [presidential science adviser George A.] Keyworth [II] was not allowed to come, although he wanted to," says another Voyager scientist.

The Reagan-appointed director of NASA. James Beggs, assured the team that "I cannot conceive of NASA without a planetary exploration program." And presidential counselor Edwin Meese III on a brief visit asserted that Reagan supports the planetary program. but added the caveat "within budgetary constraints." Mr. Keyworth is reputedly a strong supporter of the unmanned exploration program, but the scientific community has little confidence in his influence.

No matter what happens, it will be at least five years before another major planetary event. If it survives, Voyager will pass by Uranus in 1986. This is also the year when Halley's Comet returns. Planetary scientists feel this is an incredible research opportunity because Halley is the only pristine comet with a predictable orbit, and the makeup of cometary material is considered key to understanding the solar system's formation.

The Soviets, Europeans, and Japanese are mounting missions to Halley but the US mission was a fiscal casualty. Mr. Beggs said this was still under consideration, but there is only two months left for a decision.