The Halley's comet-watchers' society is one of those whimsical British spoofs created to celebrate a great occasion.Its main purpose is to hold a party in London when the famous comet returns in 1986. Meanwhile, members have the pleasure of sporting the society's necktie with the comet blazoned upon it.
But when the tie was displayed at the NASA Jet Propulsion Laboratory (JPL), headquarters of the Voyager mission, during the recent Saturn flyby, it inspired more gloom than merriment. For American planetary scientists, who have carried out one of the greatest scientific explorations of all time, Halley's comet means missed opportunity. It symbolizes the loss of impetus that the United States has let befall its incomparable planetary program.
Although at this writing some hope lingers for at least a limited mission, requests to seize a once-in-a-lifetime opportunity to send a probe to study the comet have repeatedly been turned aside in the process of drawing up the annual budget of the Natonal Aeronautics ans Space Administration (NASA). This despite the formal recommendation of the Space Science Board of the National Research Council (National Academy of Sciences) that cometary research be given high priority for this decade.
American planetary scientists are thrilled with the success so far of the planetary program. But that program is slowing down. Except for the mission of Voyager 2, now approaching Saturn to complete the survey of that planetary system begun by Voyager 1, there won't be any new planet encounter for nearly five years. After swinging by Saturn next August, Voyager 2 will head for Uranus, but won't arrive until January 1986.
"Galileo," an already authorized program to explore jupiter from orbit and to send a probe into its surface, also won't be able to get a spacecraft on target before then, even under favorable circumstances. And the circumstances do not look at all favorable. Galileo depends on the resuable space shuttle for launching. It has already been postponed because of slippages in shuttle development. It could easily be postponed again.
No other planetary missions are now authorized. The United States still has what NASA officials call a "healthy" planetary program. Much data analysis and related research are under way. At this writing, 12 spacecraft were still operating -- sampling interplanetary space, watching the Sun, orbiting Venus, and sending back valuable data. But American planetary scientists know that, as things stand now, the planetary program is in danger of running out of stream -- and they are concerned.
Speaking on behalf of all of them, the Committee on Planetary and Lunar Exploration of the Space Science Board expressed this concern bluntly earlier this year in its report on a strategy for exploration of primitive bodies (comets, asteroids, interplanetary dust.) ". . . We are alarmed by the apparent near-term prospects for a continuation of a vigorious planetary program. The pace of planetary new starts has slowed to rate totally inconsistent with achieving recommended objectives," it said.
The board was referring to the fact that the US government has long had its carefully prepared recommendation for planetary exploration in the 1980s and '90 s. These are objectives rather than specific missions. They include sustained exploration of the inner solar system, including such things as detailed radar mapping of venus and new landings on Mars, with perhaps a Mars sample being returned to Earth. Outer-solar-system exploration would include more detailed study of the giant planet systems, such as will carried out by the Galileo project. And now, with the report on so-called "primitive bodies," comets, asteroids, and space dust have been added to the list.
These bodies, which may retain many characteristics of the primitive solar system, must be studied to arrive at a balanced understanding of that system and , of course, of Earth's place in it. Scientists, as outlined in two previous articles, believe one of the biggest payroffs of planetary research is the increased understanding it yields of our own planet as we are able to see it within the larger context of the solar system of which it is a part.Comets, steroids, and the dust that has resulted from their fragmentation should provide information complementing the data being gained from studying the planets themselves and their satelites.
This is what American planetologists have in mind when they make the neglected Halley's comet mission a symbol of their concern. They see a neglect of vital aspects of a balanced planetary program. They see their country's leadeship in this field slipping. And they see a need now to take strong remedial measures.
It is this larger concern that should be remembered, because, viewed superficially, the lobbying for the Halley's comet mission that some scientists have conducted could look a little like the pleading of spoiled child. It is not as though the importance of comet research were unrecognized, or as though the world would miss the opportunity to study the Halley's object. Comet probes are part of NASA's advanced plans and will be proposed in the future. Moreover, the European space Agency has scheduled a Halley's probe, while the Soviet Union is diverting a Venus mission to pass close by the comet.
While knowledge will be served by the European and Soviet missions, however, this only underscores the concern of US planetary scientists that their own country's hard-won leadership is slipping.
In thinking now what should be done a about it, planetary science leaders such as Bruce Murray, the JPL director, first look back at what happened in the 1970s to slow the planet program. Blame is usually placed on the shuttle and on the general budgetary tightness of that era.
In Dr. Murray's view, a large part of the problem lay in a decision to place full reliance on the reusable space shuttle for future planetary missions. This , he says, meant an overly optimistic hope that the difficult technical problems the shuttle raises would be solved and that the shuttle would be available on time. Unfortunately -- and Murray says it was foreseeable -- the shuttle has run into repeated delays. What is even more unfortunate, he adds, is that production of the "old fashioned" launching rockets, which would have provided a alternative for planetary missions, was halted.
Thus even if NASA had won approval for new planetary projects that would have been launched in, say, the 1978-through-'81 period, it wouldn't have had any way to launch them. This incidentally, is one reason Murray favors a quick decision to launch a Halley's comet probe. he says one could be put together from off-the-shelf hardware that would be light enough to be launched with an Air Force rocket, yet sophisticated to make a valuable survey. It would be one of getting around the present lack of NASA launch capability and maintaining momentum in the planetary program.
Yet, this would be no substitute for a new national commitment to planetary research. As Murray himself notes, his suggested Halley's comet mission would only get what he sees as a weadkening program back on its feet. A new set of goal and a long-term plan to meet them would still have to be developed.
Angelo Guastaferro, director of NASA's Planetary Program Division, would agree that it is time for a renewal of vision. But he sees the past half decade in a little different perspective. He says there has been an ongoing commitment to support planetary research, even thought it has not been funded as strongly as in the past.
For example, he points out that Congress kept the Galileo-Jupiter mission alive even when slippages of the shuttle put it in jeopardy. The probe and orbiter were to have been launched in 1982 as a unified spacecraft.
Earth, Mars, and Jupiter will then be lined up in such a way that Mars could deflect the spacecraft to Jupiter, giving it a boost that would reduce the launch requirements on Earth. When the launch date slipped to 1984, it was realized that Mars would still be useful. But its gravity assist wouldn't be as favorable. Prove and orbiter now must be sent as seperate spacecraft. This involved the added expense of an extra launch and new spacecraft design.
Instead of canceling the project to save money, Mr. Guataferro notes, Congress voted it an extra $300 million. He explains that this doesn't do much good for scientists looking for new missions. But from the viewpoint of Congress and the administration, it was a strong new commitment of taxpayers' money to something considered very worthwhile for the nation.
"I feel there's much [more] that could be done [in the planetary program]," he says, "but it's not a going-out-of-business situation. We do have to live with the five-year gap. . . . But at the same time, we are funding scientists to do research analysis to the tune of $50 [million] to $60 million a year. We're sustaining the planetary phase in terms of tracking some 12 plenetary spacecraft that are still working -- that we put up so well they just don't quit. And in terms of that fact, there's another $50 to $60 million a year.
"On the average, with the minimum development program we have under way, we have a commitment from this [Carter] administration -- and hopefully from the next [Reagan] administration -- for a program greater than $200 million a year in solar system exploration. I believe it could be more. I would like it to be more."
Additional funds for maintaining the entire planetary research system and its worldwide facilities bring the total planetary budget to a little under $600 million a year. This supports what Guastaferro and other NASA officials believe to be a healthy program, but once which now requires new strength.
They seem this very much in terms of national purpose. Andrew Stofan, acting NASA associate administrator for space science, says, "The space program is alive and healthy, but not expanding outward. . . . I think it is extremely important that the country face the question: 'Do we want to retain our excellence and our lead in planetary exploration?'
"We do have missions in our planning. We have the Galileo. . . . The President said that he intends to have the Venus Orbiting Imaging Radar in the ' 82 budget. [This is a mission to map the Venus surface in detail, which the new administration will also have to approve.] We're looking for planetary encounters, comet encounters, later on, perhaps, a Saturn orbiter and probe.
"We recently have formed . . . a Solar exploration committee . . . to go back and again access the entire strategy of plenetary exploration and come with, hopefully, a long-term plan that this nation can commit to essentially to retain leadership in technology and plannetary exploration. The other nations do have very vigorous programs.I think it's very important that this issue be addressed as a [question] . . . of national goals."
Dr. Murray points out that such leadership can pay off in unexpected practical ways. The Voyager technology, he explains, is unprecedented in the world. It is a sophisv ticated autonomous system which, once programmed, can make its own operating decisions. It has to be able to do that because it takes so long for radio signals to reach it. Also, because it had to survive Jupiter's radiation belts, it is well hardened against radiation.
In recent years, the US Air Force realized it needed military satellites that could resist radiation and operate, if need be, without ground control. The Voyager technology was the answer to its need -- the only answer available anywhere in the world. "When you try to do something hard, you strengthen youself," Murray observes.
Now he and his fellow planetary scientists are urging the United States to continue to strengthen itselby by rising to the challenge of the demanding and highly rewarding field of planetary exploration -- a challenge that was only a dream of science fiction a quarter-century ago. They are urging the incoming administration to take a fresh look at this source of national strength, which is in danger of growing flaccid.
"The real issue now," Murray says, "is . . . do we want to continue in a path of excellence" Do we want to do things -- do we want our children to do things -- in which they can take the same pride that the American people are now taking in decisions made 10 years ago [which launched the Voyager mission]? And we willing to put more money behind them? Are we willing to put continuing commitment into them? . . .
"I think that is the very proper, current question. And I think it's part, perhaps, of a number of questions on the national scene: Where are we headed as a people? And if we intend to do things to excel, if we intend to do things we can be proud of, certainly this exploration can be one of them."