Yet fear has been leavened by fascination, and through the years, astronomers have discovered remarkable similarities between our own planet and Mars. A day on Mars lasts 24 hours and 37 minutes, there are white polar caps, and the planet has four distinct seasons, although they last twice as long as ours.
In 1976 the Viking spacecraft beamed back vivid pictures of Mars's dusty red surface and salmon-pink sky but no evidence of life-forms. At that point no new missions were planned. The space program faltered in the '80s, and as NASA struggles to recoup its battered prestige, there is a renewed commitment to explore Mars. A launch of the unmanned Mars Observer vehicle is scheduled in two years, and President Bush has called for a manned mission to Mars within the next 30 years.
A keen observer of the Mars debate is John Noble Wilford, 57, a two-time Pulitzer prizewinning writer for the New York Times and author of the recent book Mars Beckons. Wilford argues that despite the problems plaguing NASA, probing Mars offers the best hope for regaining America's once formidable presence in space. Wilford, who lives with his wife, Nancy, in Manhattan, spoke to reporter Andrew Abrahams about the allure of the Red Planet.
Why does Mars continue to intrigue us?
It goes back to the ancient civilizations. Its redness connoted blood and, hence, life. Also, Mars seemed to have very erratic movements because of its different speed of orbit, so people thought it was worth watching. With the seasons on Mars, there would be a change of color, a darkness sweeping over the planet. Early scientists and fiction writers thought that meant some kind of vegetation was expanding. Mars also seemed to have oceans and other Earth-like qualities.
Do we still cling to the notion that there is life there?
Yes. It's a residue of that old romantic fascination. A lot of the people who became astronomers and planetary scientists had grown up reading H.G. Wells and Percival Lowell, who thought he had discovered the so-called canals on the planet's surface in 1894. So if they couldn't have intelligent beings, there was still an idea there could be some life.
The Viking spacecraft did discover something, however, that is still puzzling scientists. There was evidence of erosion, areas that looked like dried-up Mississippi deltas, which indicates that perhaps in the early history of the planet, there was flowing liquid, almost certainly water. So where there may have been water, there may have been life.
How might we solve this mystery?
We could try to find some fossil evidence of early Martian life. And that's not too unrealistic. On Earth, life didn't emerge for a billion years. So in Mars's first billion years, it could have had more atmosphere and some of the same evolutionary processes that were going on here. Mars, being a smaller planet, doesn't have the gravity to hold on to its atmosphere or its interior heat. It is hard to imagine the planet experiencing a cycle that would bring back the atmosphere.
Why should we push ahead with manned exploration of Mars?
With the changes in the Soviet Union now, there is possibly a geopolitical reason that could mean going to Mars would make sense. If the Cold War is indeed over, we want to look around and find ways to incorporate the Russians—economically, scientifically and politically—into the world system. One symbolic and challenging way would be a program of joint expeditions to Mars. Not just one mission with a few guys going to Mars to raise a flag and come home. We're talking about a long-term exploration of the planet.
But can the U.S. afford to pay for this kind of commitment?
The only way we could do this is with international cooperation. Because of the cost, people say, "Why spend the money when we can learn all we want with unmanned vehicles and robots?" That's true, scientifically. So the only justification for a manned mission would be geopolitical. But we should remember the excitement of the Apollo missions. Going to the moon was a Cold War response we made to the challenge of Sputnik and Yuri Gagarin, the first man in space.
Is Mars inhabitable?
Because it bears the most resemblance of all the planets to Earth, people think it's the most habitable. But it's an extremely cold place; temperatures can plunge to-280°F and only reach a high of 0°F. Also, the atmosphere is almost totally carbon dioxide, so right there, you've got a planet you and I couldn't live on.
The first manned expeditions would have to develop an enclosed, self-supporting habitat. The Biosphere II experiment, an enclosed glass structure on three acres in Arizona where eight people will live for two years, has applications for living on Mars. It's a test of a self-sufficient, recyclable ecological system.
What are some of the likely scenarios for exploring Mars?
Hopefully, we can have unmanned vehicles ready by the end of the century. The Mars Observer will orbit the planet and conduct meteorological and geological surveys. Some of the photography would be used to locate future landing sites. The Soviets are planning an unmanned mission in 1994 with considerable help from Western European countries, particularly the French.
An area that both the U.S. and the Soviet Union have been interested in is an unmanned sample return mission. The idea is to get samples of Martian soil and rocks for future study, but the main objective would be to test the technology for sending a larger spacecraft to Mars and returning it to Earth.
What are some of the long-term benefits?
There are no obvious economic rewards. If, over the next 10 years, there's a movement towards disarmament, there are going to be tremendous dislocations in the American economy. As soon as you have massive unemployment in areas like California, you're going to have congressional hue and cry about it. One way to soften the impact and preserve the technology is to have an expanded civilian space program, with Mars as one of the centerpieces.
There is also more of a spiritual and emotional benefit. We need to have some goal that takes us beyond ourselves. We've become very ingrown as a society and live sort of defensive lives. The most dire need of our space program is to have some goals that are sufficiently challenging and that sweep us along into the 21st century. Going to Mars could get us moving again as a nation.
Of all our celestial neighbors, Mars holds the strongest grip on our imagination. Its shimmering red glow stirred such fear among the ancient Babylonians that they called the planet "the abode of the gods of war." Science-fiction writers like Edgar Rice Burroughs have spun wild and intriguing visions of intelligent life on Mars. On Oct. 30, 1938, Orson Welles frightened radio listeners across the nation with his famous War of the Worlds broadcast, a live report on a purported Martian invasion. One of this year's biggest-grossing movies, Total Recall, showed in grisly detail how hard it might be to support human life on Mars.