It has been nearly two decades since the icy sands of Mars were last stirred by hardware from another planet. In 1976, two NASA landers descended to the rock-strewn Martian landscape to take pictures and conduct a vain search for life. When the Viking landers were done, the silence of billions of years once again cloaked the red planet. Now, in the last years of the millennium, plans are under way to resume our exploration of this enigmatic world. While no one is certain when humans will first stand in the cold, thin Martian air, there is one aspect of the adventure on which all agree: Rolling robot rovers will be our point men.
On July 20, 1989, exactly 20 years after Neil Armstrong's dramatic step onto the moon, President George Bush took a dramatic step of his own. He argued for a new era in space, a time when we must "look beyond brief encounters." The president nodded in the directions of our nearest celestial neighbors, urging a return to the moon and then a mission to Mars. The so-called Space Exploration Initiative, or SEI, envisioned landing Americans on Mars by the year 2019.
Alas, SEI was soon afflicted with terminal bloat. NASA reacted to Bush's challenge with a brute-force scheme for reaching the red planet known as the 90-Day Study. Characterized as antediluvian by most of the space community, NASA's bureaucratic approach involved constructing a monstrous, 700-ton rocket in Earth orbit and eventually heaving it and its human crew in the direction of Mars. The cost was in the hundreds of billions, and the proposed rocket soon came to be known as "Battlestar Galactica."
Two years later, monetary constraints put the brakes on SEI development, and now the public shows more interest in restoring the rust belts of America than in roaming the rusty surface of Mars.
As NASA budgets have shrunk, the agency has adjusted its attitude toward space exploration. While the varied and largely unknown geology of Mars cries out for human inspection, NASA now talks about sending sheet-metal surrogates instead. If an army of scientists could be launched to Mars, robot rovers wouldn't be needed. Unfortunately, it's very expensive to transport an army 30 million miles and even more costly to feed it on arrival. Additionally, human explorers are tied to their base camps and might not be able to make substantial forays into the Martian wilderness. A final problem in blasting folks off into space is that they insist on a return ticket.
The obvious near-term solution: Hold the humans, send in the robots. Sophisticated surface crawlers can be used to reconnoiter, deploy scientific experiments, and even collect and inspect rocks. And when the
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