The time has come for America to set itself a bold new goal in space. The recent celebrations of the twenty-fifth anniversary of the Apollo Moon landings have reminded us of what we as nation once accomplished, and by so doing have put the question to us: Are we still a nation of pioneers? Do we choose to make the efforts required to continue as the vanguard of human progress, a people of the future, or will we allow ourselves to be a people of the past, one whose accomplishments are celebrated only in museums? When the fiftieth anniversary arrives, will our posterity honor it as the touchstone of a frontier pushing tradition that they continue? Or will they look upon it much as a seventh century Roman may have once gazed upon the aqueducts and other magnificent feats of classical architecture still visible among the ruins, saying to himself in amazement, "We once built that?"
There can be no progress without a goal. The American space program, begun so brilliantly with Apollo and its associated programs, has spent most of the subsequent twenty years floundering without direction. We need a central overriding purpose to drive our space program forward. At this point in history, that focus can only be the human exploration and settlement of Mars.
Mars is the fourth planet from the Sun, about 50 percent farther out than Earth, making it a colder place than our home planet. While daytime temperatures on Mars sometimes get up to 17° centigrade (about 63° Fahrenheit), at night the thermometer drops to -90°C (-130°F). Because the average temperature on Mars is below the freezing point, there is no liquid water today on its surface. But this was not always the case. Photographs of dry riverbeds on the Martian surface taken from orbital spacecraft show that in its distant past Mars was much warmer and wetter than it is today. For this reason, Mars is the most important target for the search for extraterrestrial life, past or present, in our solar system. The Martian day is very similar to that of Earth -- 24 hours and 37 minutes -- and the planet rotates on an axis with a 24° tilt virtually equal to that of Earth, and thus has four seasons of similar relative severity to our own. Because the Martian year is 669 Martian days (or 686 Earth days), however, each of these seasons is nearly twice as long as those on Earth. Mars is a big place; although its diameter is only half that of Earth, the fact that it is not covered with oceans gives the Red Planet a solid surface area equal to that of all of Earth's continents combined. At its closest, Mars comes within 60 million kilometers of our world; at its farthest, about 400 million kilometers. Using present day space propulsion systems, a one-way voyage to Mars would take about six months‹ much longer than the three-day trip required by the Apollo missions to reach the Moon, but hardly beyond human experience. In the nineteenth century immigrants from Europe frequently took an equal time to sail to Australia. And, as we'll see, the technology required for such a journey is well within our reach.
In fact, as this book goes to press, NASA scientists have announced a startling discovery revealing strong circumstantial evidence of past microbial life within Antarctic rock samples that had previously been ejected from Mars by meteoric impact. The evidence includes complex organic molecules, magnetite, and other typical bacterial mineralogical residues, and ovoid structures consistent with bacterial forms. NASA calls this evidence compelling but not conclusive. If it is the remains of life, it may well be evidence of only the most modest representatives of an ancient Martian biosphere, whose more interesting and complex manifestations are still preserved in fossil beds on Mars. To find them though, it will take more than robotic eyes and remote control. To find them, we'll need human hands and human eyes roving the Red Planet.
Copyright© 1996 by Robert Zubrin
