SEARCHING FOR ALIENS

When the first Soviet Sputnik beeped its nose at America in 1957, our society displayed a classic alarm reaction. That first human artifact to reach orbit was much less a stimulus to wonder than a sign that the American educational system had failed. Someone else had beaten us to a major achievement. Worse yet, they now had a toehold on the high ground and promised to pose a serious military threat from right over our heads. Worst of all, everyone knew they had done it. That publicly radioed "Beep -- Beep -- Beep -- Beep" made sure of that.

Some of us, of course, saw the wonder and a very different sort of promise. That little beepnik was not merely a toehold on high military ground, but a toehold on the universe, the first feeble step on a road that would lead--very soon!--to space stations, Moon bases, Mars colonies, and First Contact. After that, we dreamed, life would be richer in strange places, strange beings, and sheer adventure than it has been in centuries here at home.

And by "us," I don't mean just science fiction fans. At about the same time, astronomer Frank Drake was making his first attempt to use a radio telescope to pick up interstellar yodels--"Heellooo! Is anyone out there?"--or to eavesdrop on civilizations of planets circling other stars. Rocket scientists such as Wernher von Braun, who had been co-opted first by the Nazi military and then by the Americans (the Soviets had another set of ex-Germans), itched to shift from making rockets for delivering bombs to making rockets for putting humanity into orbit and beyond. They had published their dreams even before Sputnik; afterward people stopped thinking they were quite so nuts. The government even started tossing money their way, and it wasn't long at all before the Soviets were eating dust--why, it was little more than a decade after Sputnik that Neil Armstrong became the first human being to leave a bootmark in the dust of the Moon.

The sixties and early seventies were an exciting time to be a college student and a science fiction fan, and a proud time to be an American (despite the shames of racism and Vietnam and Mutual Assured Destruction and...). I remember it well. I also remember the dreams of what would inevitably follow that bootmark. Twelve years from Sputnik to Tranquility? Twelve more to Mars! Another twelve to the first Centaurus probe! Wow! I might actually live, I thought, to see the first reports from another star system, other-worldly landscapes, even alien faces on the news.

It didn't happen. Progress didn't stop, but it did turn Earthward. We gained solid benefits back home: weather satellites have saved billions of dollars in storm losses and lives; Earth-survey satellites have made it possible to evaluate crops, droughts, and floods, hunt for mineral deposits, and even discover ancient ruins. And modern civilization would not be what it is without communications satellites.

But we didn't get much of a space station (we had Spacelab for awhile; now we share the cramped Mir, left over from before the USSR collapsed). We don't have a Moon base. We don't have a Mars colony or asteroid mines out in the Belt. We don't have interstellar probes or starships.

Why not? What happened?

• Victory. We beat the Soviets to the top of the hill, realized that there was no way they or anybody else were about to top us, shrugged, and went home to play a different game.
  
• Money. Life (education, welfare, medical care, Social Security, etc.) got expensive back home, and Neil Armstrong and his successors saw no signs of gold mountains, diamonds as big as the Ritz, or abandoned alien bases on the Moon. So why bother?
  
• Truth. We visited Mars. We did it with the robotic Mariner flybys and Viking landers, and they showed us that Mars was lifeless, cold, dry, and real short on oxygen. Lowell's canals and Burroughs' Martians just weren't there. So once more, why bother?
  

Lacking meaningful competition, get-rich-quick opportunities, and the romance of big-bosomed Barsoomians, the space program diminished. It continued--scientists have been able to keep NASA convinced of the need for Hubble telescopes and Voyager and Galileo spacecraft (among others) to explore the solar system. Drake and his fellow yodel-hunters kept on searching the skies for signs of extraterrestrial intelligences, steadily improving the technology and even sending off a yodel or two of their own.

But we haven't been back to the Moon for over twenty years. We dropped Gerard K. O'Neill's dreams of giant orbiting habitats. We decided the up-front bill for solar power satellites--even using Lunar raw materials--was too high. There's been talk of Mars missions, even Presidential proclamations that Mars was the Place to Go, but precious little action. The grand dreams are dead (though construction on the long-promised and constantly redesigned Freedom space station will begin Real Soon Now--maybe).

Or maybe they've just been dormant, waiting for new technology to make getting out there a little easier and cheaper and for new discoveries to draw us out there. Some of those technologies include:

• The Hubble Space Telescope, which has despite its initial astigmatism done an astonishing job of showing us the cosmos, including planets orbiting other stars. At the same time, ground-based equipment has also improved. The tally of extra-solar planets is now pushing a dozen, and if they all seem much too large (larger than Jupiter) for us to think them very comfy, they at least demonstrate that other stars do have planets. And William Borucki of NASA's Ames Research Center in Mountain View, California, said in 1996 that he expects detection of "the first Earth-like planet orbiting a sunlike star" as early as 2001 (see Science, 25 October 1996, p. 495).
  
• Advances in electronics (when Neil Armstrong went to the Moon there was no such thing as a desk-top computer), which have made possible much smaller and hence cheaper robotic missions, with the potential for "telepresence"--letting human beings view the scenery and operate the machinery from back home. With telepresence, it will be possible for Internet surfers to link to a Mars rover or a Jupiter orbiter and participate in the mission. That is, if we can't go in person, at least we can go in "virtual" person, as a sort of disembodied viewpoint. (See John Merchant, "A New Direction in Space," IEEE Technology and Society Magazine, Winter 1994.)
  
• Vertical-take-off-and-landing space vehicles, which promise to reduce greatly the cost of reaching orbit with either machinery or people. They have actually been developed and demonstrated. The grand example is the McDonnell-Douglas DC-X (see G. Harry Stine's Halfway to Anywhere: Achieving America's Destiny in Space [New York: M. Evans & Co., 1996]). A competing Lockheed design won the NASA contract, but if the enthusiasts are even half right, we'll soon see spaceports right out of the old sf movies.
  

These technologies are thus showing us there's someplace to go and promising to make it possible to go there more cheaply than ever before--especially if all we have to launch is small robots able to carry a few virtual passengers. And it's enchanting to think that other intelligent species may have done much the same. Perhaps someday one of our little robots will face another, and you or your grandchild will peer out of the camera at--another camera! (And it will drive us nuts, wondering what's looking at us.)

But wait a minute! Is there any reason to think there's anyone out there? The yodel-hunters haven't found a thing. Nobody's ever produced convincing evidence that Earth has ever been visited by aliens (forget the alien abduction fantasies and the persistent but baseless rumors about Roswell, New Mexico). When the Viking landers sampled the Martian soil in the mid-1970s, they got results that made a number of scientists (including me, in articles I wrote for Astronomy Magazine) think of biochemistry, but the consensus came down to simply unfamiliar soil chemistry.

Here's where the new discoveries come in:

We've spotted a few other planets, so we know there are such things (see above).

Antarctica has the curious habit of collecting meteorites. They fall from the sky onto the ice, get covered with snow, and ride with the motion of glaciers. In some spots, the ice gets shoved up against mountain ridges, where the wind wears the ice away and exposes meteorites embedded in the ice. When human beings come along, they then find the meteorites sitting on the surface. Some folks have made a profession of collecting them. And a dozen of these meteorites have been identified with some confidence as coming from Mars, blasted loose when asteroids or comets struck the Red Planet. (Others have come from the Moon; most are remnants of asteroids and comets.)

In addition, Antarctica is not terribly hospitable. Not much grows there, so that any rock one picks up is relatively unlikely to have been contaminated with terrestrial lifeforms, at least in its interior.

In 1996, Martian meteorite ALH 84001, aged some 3.6 billion years, bounced into space some 14-18 million years ago, caught by the ice 13,000 years ago, and found in Antarctica's Allan Hills in the mid-1980s, was taken apart and examined. In its interior crevices, reports a team of researchers led by Everett Gibson of NASA's Johnson Space Center, are structures shaped like unusually small bacteria and made of materials consistent with life. They look a lot like fossils of similar 3.6-billion-year vintage found right here on Earth.

Are the thingies from meteorite ALH 84001 fossils too? Well, planetary researchers agree that very early in its history Mars had liquid water on its surface, a thicker atmosphere, and a warmer climate (see Jeffrey S. Kargel and Robert G. Strom, "Global Climatic Change on Mars," Scientific American, November 1996). Maybe, they say, these benign conditions lasted long enough for life to appear (we know it didn't take long on Earth--the oldest fossils are about 3.8 billion years old, and the planet itself is only 4.6 billion years old). And there's a hint that life may have lingered on Mars for a long time; British meteoriticists Colin Pillinger, Ian Wright, and Monica Grady of the Open University in Milton Keynes have found tantalizing chemical hints of Martian life in another meteorite (EETA 79001) that left the Red Planet only 600,000 years ago (see Science, 8 November 1996, p. 918).

What's more, unusually small bacteria (nanobacteria) exist on Earth today. And bacteria are found in cracks in the Earth's crust, even miles below the surface. In fact, Stephen Jay Gould suggests that there may be more living material in these crack-dwelling bacteria than in all the oceans, jungles, and cities on the surface (see his Full House [New York: Harmony, 1996]). Indeed, sheltered deep beneath the frozen or roasted surfaces of most planetary bodies throughout the cosmos, provided with moisture and carbon (both present in deep rock) and fueled with chemical energy instead of sunlight, life may thrive. It just won't look very impressive to us.

Is there life on Mars, then? Or anywhere else other than Earth? We don't know. But there are some tantalizing hints that have got a number of people excited enough to think more seriously than they have for years about a Mars mission. They don't expect to find intelligent Martians or the ruins they left behind, but they do think there's a distinct possibility that in the cracked rock beneath the surface, down deep where the ancient warmth and moisture yet linger, there may be something a lot like Earthly bacteria.

If they're right, and if we could just find samples of true extraterrestrial life, no matter how simple and primitive and unintelligent, the impact here at home would be tremendous. Some religious folks are already mounting their ramparts. More significantly, we would know that Earth truly is not unique in its hospitality. Life can appear on other worlds--if on Mars, then perhaps on Europa (in the liquid sea planetary scientists think lies beneath the ice), perhaps among the clouds of Jupiter, and certainly on the more Earthlike worlds we can be sure circle other stars in our galaxy, and in other galaxies throughout the universe.

And, thinks the unreconstructed fan of that Old-Time science fiction, if there is life on other worlds, then there must also be intelligence, not everywhere of course, but on many more worlds than one. If there is intelligence, there must be civilizations. If there are civilizations, some must be as advanced as ours, or more so. There must be interstellar empires, and there must be hope for our grandest dreams, for the long-awaited First Contact, for generation ships and colonies and empires of our own.

And as luck would have it, 1996 was not a year just for discoveries. It was also the year when the international space community launched a massive effort to put a few robots on Mars. Sadly, the November 16 launch of the Soviet Mars '96--a package containing an orbiter, two landers, and two soil penetrators--failed. As the spacecraft reached orbit, its engine misfired. One hundred and eighty million dollars' worth of equipment, contributed by researchers of several nations, wound up in the Pacific. It seems unlikely that the mission can be repeated anytime soon.

The U.S. launches of the Mars Global Surveyor, designed to photograph the planet from orbit, inventory rock types, and map future landing sites, and of the Mars Pathfinder, which includes the solar-powered "Sojourner" robot microrover, were successful (though one of Global Surveyor's solar panels did not properly deploy). Both are now on their way to Mars, with Pathfinder scheduled to arrive on the Fourth of July and Surveyor in the autumn of 1997; you can catch progress reports on the Internet by visiting NASA via the Internet. Neither will be able to settle the question of life on Mars (the Soviet landers and penetrators might have helped here), but they mark a new stage in our willingness to reach outward.

If they do find hints of life, we will need to mount further expeditions to learn more. We may even send human explorers, though it will be a few years before that is possible. We need the space station first. We need a base on the Moon, where we can mine some of the materials needed to build the Mars ships.

Such things are expensive. It costs a great deal--even if the new launch systems prove as economical as billed--to lift the necessary components, crews, and supplies for space stations, Moon bases, and Mars ships. Fortunately, another one of those recent discoveries may help here.

It was once thought that Lunar materials would include not only metals but also water, in the form of buried deposits of ice. It would be invaluable not only because it would be needed to support human life in stations, bases, and ships, but also because water molecules can be split with electricity to yield hydrogen and oxygen. Humans need the oxygen. Rocket engines need both hydrogen and oxygen for fuel, and they need them in great quantities. Water on the moon would mean saving the expense of fueling Mars ships from Earth. It would also make possible economical refueling of Moon rockets, orbital buggies, and Space Shuttles.

And early in December 1996, the Defense Department announced that its Clementine spacecraft (launched in 1994) had detected signs of water ice deep inside a shadowed crater near the Moon's South Pole. The ice may have been delivered when a comet or comets smashed into the moon; the heat of impact--as well as the heat of the lunar day--would then have vaporized the comet's ice, and the vapor would have frozen out as frost on the Moon's night side and shadowed surfaces. Those surfaces which were later struck by sunlight would have lost their traces of frost. Those that stayed dark, as in deep polar craters, would have kept it, and over eons, the frost would have accumulated. Today, says the Defense Department, there is a patch of ice or frost-impregnated gravel about 25 feet thick and roughly the size of a small lake or pond. This is by no means a huge quantity of water, but as Dr. Paul Spudis of the Lunar and Planetary Institute told CNN, "Water is probably one of the most valuable strategic materials we can find" on the Moon. The "Clementine deposit" may be enough to supply a base or two and enough spaceships to get us out to where larger quantities of potential rocket fuel await us, among the moons of Jupiter and Saturn, or perhaps to intercept a comet as it delivers its load of ice closer to our doorstep.

And then? Well, we know there's somewhere to go. We're getting better, cheaper technologies to get us there, if we choose to go. And we're finding reasons to go.

Perhaps we will go.

The dream still lives.