The prospects of US efforts to explore the planets appear brighter than they did a year ago, but are still marred by major political uncertainties.
This is the assessment of many scientists intimately involved in America's planetary program. They have gathered here this week for the annual get-together of the planetary science community, the meeting of the Division of Planetary Sciences (DPS) of the American Astronomical Society (AAS). Somewhat uncharacteristically, talk in the corridors and restaurants centered as much on politics as on the esoteric details of Saturn's rings or the latest theories on the nature of Jupiter's giant red spot.
''A year ago, we were in a state of consternation,'' recalls Michael J. S. Belton of Kitt Peak National Observatory and the outgoing chairman of DPS. ''Today, the panic is gone but the same problems and concerns remain.''
Last year the planetary program was ''clearly on a going-out-of-business profile'' acknowledges Jessie Moore, director of the National Aeronautics and Space Administration's (NASA) Earth and Planetary Exploration Program. Several major missions were canceled. Federal funds for planetary exploration, which had been declining slowly for a decade, appeared to be heading into a nose dive.
The situation galvanized leaders of the planetary research community into an aggressive lobbying effort. They won enough support in the White House, Congress , and NASA management to restore much of the program that had fallen to the Office of Management and Budget's (OMB) ax. Most important, the ambitious but repeatedly delayed Galileo mission that will probe the solar system's largest planet, Jupiter, was put back into the budget.
Burton Edelson, former vice-president of Comsat Corporation and NASA's associate administrator for space science and applications, tried to reassure the planetary scientists that the White House strongly supports space science and that the federal space science program is ''healthy and growing.'' Current programs are ''tremendous in every respect: They excite the mind, challenge engineering, and dent the pocketbook,'' he said, hastily adding that they are worth the money. Dr. Edelson pointed out that, relative to other programs, space science has fared quite well, receiving more than a 20 percent increase in the fiscal 1983 budget.
''I know that planetary science has had some traumatic jolts in recent years, . . . but that's behind us now,'' Edelson declared. Administration deliberations on the fiscal year '84 budget are tightly embargoed, but ''all the signs are positive'' that the planetary program will be favorably treated, he asserted.
A number of the scientists were critical of his performance, however.
''Who does he think he's talking to, telling us we're better off. We're better off, like being stood up against a wall and shot is better off. It's his lack of candor that really bothers me,'' commented one disgruntled scientist.
The increase in funds is due to decisions made long ago, not to anything the administration has done, objects Louis Friedman, executive director of the Planetary Society, a nonprofit public-interest group formed to support planetary research. ''You can't go by the bottom line. You have to look at what's going on. And there has been nothing new for five years,'' he explains.
US Rep. Tim Wirth (D) of Colorado presented the researchers with a far more stark view of their future. As a founder of the House ''space caucus'' he was one of the congressmen instrumental in rescuing the planetary program last year.
''In the next two years, the White House will try to cut the planetary program by 50 percent,'' he predicted. The combination of the projected $200 billion deficit and Mr. Reagan's refusal to countenance reductions in defense spending mean that the OMB's 1984 budget will be ''the most brutal we have seen yet,'' Representative Wirth maintained.
For the planetary program, he anticipates that this will translate into existing spacecraft simply being turned off, that a new mission to map the surface of cloud-locked Venus using radar that NASA is hoping to get authorized in '84 will not be included, and even that the US weather satellite program may be threatened. He warned the scientists that they must become even more deeply involved in the political process if they expect the US planetary program to survive.
The administration considers even a relatively modest planetary exploration program ''as too expensive for the richest and greatest nation the world has seen,'' objected Donald Hunten, chairman of the Committee on Planetary Exploration of the National Academy of Sciences, adding with deliberate understatement, ''Some of us have some trouble with this assessment.''
This is a period of space exploration, similar to the Age of Magellan, the period in the 1500s when European sailors explored and mapped the world oceans, Dr. Hunten argued. ''I just hope the United States doesn't follow the example of Portugal'' which faded into obscurity following this period.