NO OTHER planet has quite stirred the human imagination as Mars has.
Astronomer Percival Lowell suggested early in this century that grooves crisscrossing the red planet were canals that had been built by ancient civilizations. Orson Welles frightened millions of radio listeners in 1938 with his seemingly real news accounts of Martians invading Earth. Novelists ranging from Edgar Rice Burroughs to Ray Bradbury have conjured up vivid scenes of life there.
Humans have long been fascinated with the idea that life may exist on Mars. While scientists say no evidence has been found to support this, they do not rule out the possibility that life may once have been present there. And they say Mars` atmosphere offers the most suitable environment for human colonies of the planets in the solar system.
Serious proposals were drawn up in the 1960s for human expeditions to Mars. But those plans were dropped after the completion of the Apollo lunar missions–victims of budgetary cutbacks and waning public interest in the space program.
Today, the tides of public opinion appear to be flowing in the direction of a human mission to Mars. Scientists have once again begun to quietly draw up ambitious plans for a Martian expedition. Space enthusiasts have organized conferences to discuss Mars. A few politicians have stepped forward to support such a venture.
And recently, a full-day symposium on human exploration of Mars was held at the National Academy of Sciences in Washington. Among those who said the time is ripe to begin planning for man`s first interplanetary mission were Sen. Spark Matsunaga (D., Hawaii); Harrison Schmitt, a former U.S. senator and astronaut; Sally Ride, the first female American astronaut; and Carl Sagan, the Cornell University astronomer and popularizer of science.
They were joined in their appeals by the crew of Soviet cosmonauts and American astronauts who linked their spacecraft during the joint Soyuz-Apollo mission in July, 1975. Most of the symposium`s speakers favored a cooperative international effort to send people to Mars in the late 1990s or first decade of the 21st Century.
To be sure, the wave of popular support hasn`t built up much momentum so far. Space agency officials say such a trip would cost $30 billion to $40 billion. They are aware that record federal deficits have made many members of Congress wary of embarking upon such an ambitious undertaking.
But space enthusiasts argue that if a truly international effort were organized–one involving the United States, the Soviet Union, Europe and Japan –the cost could be affordable for each nation. And they say such a cooperative effort could help reduce global tensions, answer important scientific questions and provide valuable technological spinoffs.
”A mission to Mars could be done for less than what it cost to send man to the Moon,” Sagan said, adding that the $40 billion price tag would be about half of the cost of the Apollo lunar program ($75 billion in today`s dollars). He estimated that such a voyage would amount to only a small fraction of the estimated cost to fully deploy the proposed ”Star Wars”
defense system.
Sagan acknowledged that the cost of such a mission could not be justified in terms of scientific benefits alone. Robotic missions–such as the Mariner 9 flight in 1971 and the Viking probes that landed on Mars in 1976–could gather almost as much scientific data as a human mission at less than one-tenth the cost.
But Sagan said there were other reasons for a human mission, which cannot be quantified in terms of costs and benefits. ”There is an exploratory, open- road, outward-bound spirit that has marked us since our hunter-gatherer days,” he said. ”Our first interplanetary mission would be a historic event, remembered in the same way we remember the journeys of Columbus and Magellan.”
James Beggs, administrator of the National Aeronautics and Space Administration, said a voyage to Mars could help answer the question about whether life ever existed on that planet and provide important clues to explain how the solar system was created.
Some scientists even believe that Mars could help solve the mysterious disappearance of dinosaurs on Earth. One recent theory is that a swarm of comets struck Earth 65 million years ago, throwing up vast clouds of debris that chilled Earth and led to the dinosaurs` extinction. Scientists say these comets would have struck Earth and Mars about the same time. If such a celestial event did occur, evidence should be present in Mars` pockmarked landscape.
One thing is for certain: When the day comes that humans first step onto the surface of Mars, they will witness some spectacular sights. Even though Mars is only about half the diameter of Earth, it has a volcano three times as high as Mt. Everest and a canyon three times as deep as the Grand Canyon. Swirling storms of red dust sometimes engulf the planet for weeks at a time.
Despite the dust storms, Mars offers the most hospitable living arrangements–outside of Earth–of any planet in the solar system. It has an atmosphere, relatively moderate surface temperatures and water. Its gravity is about one-third of Earth`s. Its red color is caused by the abundance of iron oxide in its rocky surface.
But the journey to Mars would be vastly more complex than the lunar missions. Earth is about 240,000 miles from the Moon. The closest Mars ever comes to Earth is 35 million miles.
The journey also would be far more hazardous than a trip to the Moon. Nobody really knows how the human body would adapt to the near-weightless conditions of space during extended periods. Scientists know that bones tend to deteriorate and muscles atrophy after long periods without gravity. In addition, more than half of the astronauts have suffered from some motion sickness in space.
Special diets, drugs or exercise may have to be developed to deal with these physical problems. Engineers may need to design a spacecraft that slowly spins–thereby creating artificial gravity on such a voyage to match the gravity found on Mars.
Human voyagers in space also would face potentially lethal amounts of cosmic radiation given off by the Sun in the form of solar flares. These intense bursts of radiation are unpredictable and difficult to forecast. For these reasons, the spacecraft would have to be equipped with special ”storm shelters” that would protect humans if such a flare were to occur. Scientists say that the risk on lunar missions has been relatively low because the flights have been of relatively short duration, but on longer flights the risk would be much greater.
A lengthy space voyage also would create special medical and psychological problems. A doctor would almost certainly have to be among the crew members to provide medical care if an emergency were to occur.
Billie Jean Bluth, a NASA sociologist in Washington, notes that Soviet cosmonauts suffered from depression and lethargy after seven-month space missions. Toward the end of one trip, cosmonauts began sleeping 12 hours a day in an attempt to escape their situation.
A 1984 report by Science Applications International Corp. in Schaumburg, Ill., outlined one possible mission to Mars. The materials for the spacecraft would be carried into orbit on 18 shuttle flights and then assembled at a space station placed in Earth`s orbit during the 1990s. The Mars spacecraft would weigh at least 10 times as much as the vessels used during the lunar missions; most of the additional weight would be fuel.
The space journey to Mars would take about six months. Under one scenario the space crew would remain on Mars for about 30 days before returning to Earth on a 2 1/2-year return flight. The return trip would be much longer because of the changing alignments of the planets as they hurtle through space on their respective orbits.
A more probable scenario would call for the astronauts to begin setting up a permanent base on Mars. This habitation would provide the air, food and fuel needed for a stay that might last about 16 months. It also would be the staging ground for future missions to mine the asteroids, the minor planets that lie between Mars and Jupiter, or visit other planets.
The astronauts would be able to manufacture much of the air, water and fuel they would need by extracting materials from the atmosphere and surface of Mars. The Martian atmosphere–consisting of carbon dioxide, nitrogen, argon and water vapor–offers a ready source of oxygen and water. In addition, some water is contained in the planet`s frozen polar icecaps.
Benton Clark, an engineer who worked on the Viking project, said the Martian soil contained the raw materials needed to make portland cement, plaster of Paris, ceramics, glass, fertilizers, rocket propellants, explosives, metals and even food.
”Mars compared with the Moon is like the Garden of Eden compared with the Sahara Desert when it comes to material resources,” Clark said.
The recent push for Mars can be traced to the University of Colorado in Boulder, where a group of graduate students began holding informal seminars in 1978 on the ”habitability of Mars.” Their discussions sparked interest among space groups around the country, and they became known as the ”Mars Underground.”
In 1981, the graduate students helped organize a ”Case for Mars”
conference in Boulder during which planetary scientists brainstormed about the technological possibilities of a Mars mission. A second conference was held in Boulder in 1984, during which detailed engineering and scientific studies were discussed.
Most space enthusiasts believe that Earth`s first interplanetary mission will have to be an international effort. They note, for example, that already more than half of the current space missions involve more than one country. A growing number of space shuttle crews are multinational.
”If the U.S. and USSR worked together on an ambitious space project, both countries could redirect some of their most advanced capabilities and energies from military competitiveness to peaceful cooperation,” said Louis Friedman, executive director of the Planetary Society, a non-profit group that is the nation`s largest organization of space enthusiasts.
And Beggs, the NASA administrator, said he believed that a manned Mars mission could shift the superpowers` emphasis from planning for nuclear war to preparing for interplanetary exploration. He said: ”Ironically, Mars, the primitive symbol of the god of war, could become a powerful instrument for peace.”
