The Sciences

Exploring the Limits

By Bruce MurrayNov 1, 1992 12:00 AM


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Thirty years ago a band of intrepid young Jet Propulsion Laboratory engineers and university scientists set out to do what seemed impossible: they committed themselves to design, build, and launch the first-ever picture-snapping probe to Mars. At the time only a pitifully underpowered rocket was available; the United States still lagged way behind Soviet Union rocket power five years after Sputnik had blasted open the space age. Yet the scientists gave themselves just two years to transform their untried ideas into reliable hardware for the unprecedented eight-month celestial voyage.

I was one of those scientists, helping to design the robot’s diminutive television eye. We all were obsessed with the thought of seeing the fantasy world of Mars and of being the first to do so--if the Soviets didn’t get there before us. They had tried twice unsuccessfully. But win, lose, or draw, we all felt we were part of the future, terribly lucky to be on the cutting edge of history.

We beat the odds and the USSR. On July 15, 1965, tiny 575-pound Mariner 4 whispered back a few TV glimpses of an alien world. Everyone hoped Mars would be another Earth. The TV networks camped noisily outside JPL’s gates, while we struggled to make sense of the faint signals. Then, finally, there it was. Not the poetic abode of Ray Bradbury’s Martians, but instead an ancient uninhabited surface, stranger than any fiction.

Those first fuzzy Mars pictures were big news. President Lyndon Johnson and the Senate and the House got special showings. I happened to be the one who presented the pictures to the Senate Space Committee, whose chairman was Senator John Stennis from Mississippi. I went through my little song and dance, enthusiastically interpreting the faint Mars features. Afterward he said in his heavy southern drawl, Son, I didn’t understand a word you said, but it was great! He didn’t care about the details; he was just excited because the United States, first among nations, had done the impossible.

We aren’t doing the impossible anymore. Today the civil space program of the United States is demoralized, bogged down, and ruinously expensive. We aren’t going anywhere. Like a sleeping Gulliver captured by the Lilliputians, over the two decades since the Apollo flights to the moon NASA has become bound up in special-interest relationships.

The space agency hit its low point in mid-1991. It started a full-blown Space Station Freedom project to symbolize American leadership in space in the year 2000--and to guarantee NASA employment indefinitely. Rejecting simpler, more practical, and cheaper approaches, our national leadership embraced symbolism over substance, and politics over performance. Freedom is, in fact, an orbiting pork barrel. The aerospace companies who want to build it plan to parcel out high-tech piecework to just about every congressional district in the land, thereby assuring a broad base of congressional support. But a dreadnought circling Earth in low orbit so long after America boldly rocketed astronauts safely to the moon and back is actually a symbol of not exploring. An uncertain America may now try to redefine the frontier of space as convenient low-Earth orbit. But in our optimistic youth as a space-faring nation we reached farther, and we changed human expectations forever.

How did we end up in such a mediocre state after such an exciting beginning? Why did America make the effort and take the risk to be first to Mars with robots and first to the moon with human astronauts? Why aren’t we willing now to set off toward Mars with humans?

Nations and individuals have always explored for gold, glory, or curiosity. Five hundred years ago countries competed for new lands and the acquisition of raw materials, and that motivated exploration. Two hundred fifty years ago the search began to shift to mysterious peoples in exotic, remote locales. Tahiti, Australia, and central Africa were part of the romantic unknown. Then on to the geographic limits of Earth--the Northwest Passage, the North Pole, and finally the race to the South Pole. After World War II, underutilized Navy ships and airplanes opened up Antarctica to sustained scientific exploration. For the first time curiosity and binding international agreements guided major national explorations. Antarctica today gives us a glimpse of how humanity in the next century can transcend ethnic and national egocentrism.

Away from the silent ice of Antarctica, however, cold war rules prevailed. Pursuit of national glory powered the leap into space. Space- traveling humans and robots became the supreme symbols of technological achievement. The USSR spawned startling early successes, and President John Kennedy responded in 1961 by challenging the Soviets to a technological race--men on the moon by the end of the decade. Billions of people throughout the world watched Neil Armstrong’s first step onto the austere lunar landscape on July 20, 1969.

By 1972 U.S. astronauts were racing electric cars across rocky lunar plains. That’s when NASA and JPL won government approval to boldly go where no thing had gone before. This time they proposed to send smart robots to the very edge of the solar system. This new probe was to be a lineal descendant of Mariner 4 but one dramatically enhanced to fly through Jupiter’s radiation belts and on to Saturn. Best of all, if JPL could get this complex beast designed, built, tested, and on the launchpad by August 1977, the mission could exploit a rare celestial alignment and ride free all the way out to Uranus and Neptune.

This was the greatest exploratory opportunity I could imagine. But again, the people with the money were interested in how it would play out on the cold war stage. So in February 1972 I received a discreet but anxious phone call from a professional colleague within the Nixon White House. The president wanted more justification for this challenging new mission. Nixon wasn’t the space supporter that Kennedy and Johnson had been. It could be incredibly visual and popular, I said, having labored long and hard with the planning team to exploit this latest imaging opportunity. But my most compelling argument was the international contest: It’s certainly the most cost-effective space competition with the Soviets imaginable. The project got the thumbs-up.

The twin spacecraft, now named Voyager 1 and Voyager 2, broadcast back a spectacular reconnaissance of Jupiter and Saturn in 1979, 1980, and 1981. And Voyager 2 did indeed catch that rare celestial alignment. In August 1989, as if to counterpoint the imminent collapse of the Soviet empire, Voyager 2 raced past Neptune, the outermost world of our solar system. It arrived there barely three decades after the launching of Sputnik and less than four centuries after Galileo first viewed the planets through his primitive telescope. Voyager was an extraordinary electronic zoom lens linked via mass communication to the eyes and brains--and curiosity--of billions of people on Earth.

Voyager 1 and 2--and their smaller precursors, Pioneer 10 and 11- -obediently continue to radio their findings from the very edge of our solar system back to an immensely changed America. Truly, their signals are a faint, distant echo of John Kennedy’s 1961 Apollo speech--a last hurrah for that fantastic burst of American technological capacity in service of human imagination--and cold war competition.

That crew-cut 30-year-old enthusiast and partisan who helped with Mariner 4’s TV camera is now a graying 60-year-old who advocates hard for international cooperation in space. The cold war has ended. America is no longer the supreme cultural, political, and economic force that it was. Indeed, the era of empires is over, be they Spanish, Portuguese, British, French, German, Soviet, or American.

But there is a deeper and much more serious American problem. We no longer have a confident vision of ourselves leading anywhere. Like Lot’s wife in the Old Testament, we are too strongly tempted to look backward, and as in the biblical account, we are in danger of being immobilized. NASA looked backward to the cold war by placing symbolism over substance with Space Station Freedom. Now the prospect of Freedom’s great cost and small significance paralyzes our whole civil space effort.

What do we have to look forward to? Is the excitement of exploration gone for our times? I don’t think so. I’m hopeful that my children (if not I) will gaze in wonderment on the first close-up images of Pluto, of the unexplored half of Mercury, and of the tarry surface of Saturn’s cloud-enshrouded moon Titan. Perhaps they will even see Venus’s surface close up through the robotic eyes of some novel submersible that will periodically dive down through the scalding hot envelope of carbon dioxide gas surrounding that planet, explore briefly, and promptly ascend. And surely the fascinating landscape of Mars will become more familiar to everyone as robotic rovers, probably from several nations, crawl about its vast surface, looking, touching, feeling, tasting.

Indeed, Mars tugs at our imaginations just as the moon did at the beginning of the space age. Mars is inevitably the next place to go with humans after the moon. It offers the only potentially habitable surface in the solar system besides Earth. Oxygen, carbon, nitrogen, and hydrogen, the critical elements for life, abound at Mars’ harsh but survivable surface. Probably a small outpost will operate there during the next century. By the end of the twenty-first century there might even be a permanent base, similar to the base at the South Pole that the United States has supplied by air for many decades. I hope that the Mars base will be international, representing Planet Earth. That would be a grand escalation of the twentieth-century Antarctic experience into the twenty-first century.

Before we get there, robotic spacecraft will blaze a path in space for human explorers once again. In the 1960s more than a dozen robotic scouts paved the way for the first human visitors to the moon. Mars is much larger and more complex. The Mars explorers can’t return in just a few days if things go badly, as the Apollo explorers did. So the first human footprints on Mars must be preceded by many robotic scratchings. Why not pool the considerable robotic capabilities of the United States and Russia, supplemented by Europe and Japan? Indeed, the international exploration of Mars could be a major unifying theme of post-cold war space activity. What counts is making the journey in good company, not racing to prove national manhood.

There are also speculations about terraforming Mars. Terraforming means artificially changing a planet’s surface and atmosphere to make it habitable for humans. However, humanity’s problem for the next century is that our home planet is becoming less habitable. We are reverse terraforming Earth. The overriding challenge of the next century will be to bring humanity into a sustainable balance with the rest of Earth’s biosphere.

Assisting in that great task through remote sensing will be a priority task for space endeavors. Thus, for me, worrying now about how to modify another planet is not very timely.

Where, then, will future bursts of humanity’s energy lead us? Indeed, a number of my colleagues think our destiny lies way beyond Mars-- that Voyager has put us on the pathway to the stars. But I’m not so sure. Such films as Star Trek, 2001, Star Wars, Alien, Close Encounters of the Third Kind, and E.T. testify to the popular acceptance of interstellar travel. But the stars are very, very far apart. Our nearest stellar neighbor is so distant that its light is more than four years old by the time it reaches us. That’s four years at the speed of light. For humans to travel there would be a one-way journey requiring many generations. Who would want to be locked up, to live, breed, and die, in a giant sealed space canister? The icy plateaus of central Greenland and the Antarctic offer far more attractive locales for colonization, still bathed as they are from time to time with blue sky, moonlight, and breathable fresh air. So unless there are wormholes and parallel universes or some other kind of unimagined new physics, human star travel is simply not going to happen on any time scale. Maybe that’s why aliens aren’t visiting us (despite reports in the supermarket tabloids).

We will have to send our senses where we ourselves cannot go. We already know how to build robots adapted to the vacuum and radiation of space, like Mariner 4 and Voyager. Indeed, I have pondered hard about how to make microminiaturized Voyagers that could one day streak deep into the galaxy. However, even for robots the stars are very far apart. If an automated probe is to send back results, say, 30 years after launch--a considerable length of time to expect contemporary societies to wait for results--that spaceship must reach a speed at least one-fifth that of light itself. At such speeds a collision with a tiny grain of interstellar dust becomes a miniature atomic explosion. That’s an academic point, anyway; we just don’t know how to make ships go nearly that fast. Human ingenuity in the future may stretch our robotic reach to touch the envelopes of a few nearby stellar neighbors. But my intuition is that we won’t be able to go much farther.

That doesn’t mean we can’t keep exploring. We will continue probing the cosmos ever more deeply and more finely through telescopes on the ground, in Earth orbit, and on the moon. And by far the most interesting thing to strive for in outer space is evidence of alien intelligence--proof that we are not alone. I and many other scientists find it hard to accept the proposition that intelligent life started only on this single planet orbiting the rather undistinguished star we call the sun. Millions of comparable locales dot our galaxy.

In fact, scientists listen right now for radio signals from alien beacons. And in a hundred years Earth should be technically capable of detecting all manner of alien beacons, not just those radio signals that might be spoon-fed to this particular stellar location. My great- grandchildren should have proof that a communicating galactic network exists--and begin to wonder if it accepts new members. Their generation may ponder whether to build giant interstellar transmitters to follow up the beacon signals. And if perchance the cosmos still seems devoid of signals after a century of systematic searches, they will be justifiably puzzled.

I’m an optimist. Anyone who hopes to find a radio needle in a universal haystack would have to be. And my optimism extends to our species. We are relatively young, a product of the late ice ages, and we are growing up. That means coming to terms with limits, both in space and here at home. Over the next several centuries, I think, aggressive and expansive Homo sapiens will finally evolve a benign, sustainable equilibrium with its surroundings after so many millennia of relentless geographic and demographic expansion. Indeed, our distant descendants may look back upon our times of reckless growth and destabilizing technological change as the adolescence of the species. I don’t think humanity is doomed to the eternal hellfire of technologically generated instability, forever to be a half-savage waving a pistol, never able to overcome fully his animal origins. We are free to grow up--or to fail.

Few may remember the thousandth anniversary of Columbus’s voyage come A.D. 2492. By then, the emotional, intellectual, and moral potential of Homo may be bursting forth, after being obscured only for an adolescent interlude by the sound and fury of electricity, rockets, and splitting atoms. Our task is to be good ancestors, so our distant descendants can mature and find their place in the Galactic Community.

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