Onward to Mars

From the Kennedy Space Center and the Soviet Union's Baikonur Cosmodrome, powerful shuttles and unmanned rockets lift off week after week, bearing construction modules and fuel supplies to a giant space station in earth orbit. There, skilled workers have been assembling the ship that will take the first humans to Mars. After more than a year of construction, the million- pound, ungainly looking spacecraft is ready. With a crew of eight, it separates from the space station and heads for Mars, following the Hohmann ellipse, a space trajectory that may one day be as familiar as a great-circle route over the North Atlantic.

Twenty days later, the blue-white earth has shrunk to a bright dot of light against the background of stars in the eternal night of outer space. Looking back, the crew members are filled with a sense of isolation, a feeling that will never quite leave them during the 280-day outbound leg of their journey. A busy schedule provides some distraction. The space travelers perform scientific experiments, practice taking shelter against solar-flare radiation, tend vegetables in their hydroponic greenhouses, exercise vigorously for several hours each day and tap into digital libraries for music, light reading matter and courses in Martian meteorology and geology.

At first they are able to communicate easily with controllers on earth. But as they head farther into space, the time required for their radio signals to reach earth lengthens to minutes, and the ever widening gap between questions and answers makes conversation difficult. Now, with the earth more than 100 million miles away, Mars is looming in the spacecraft portholes, and the crew begins preparing for a yearlong adventure on another world.

A manned trip to Mars, long the stuff of science fiction, now appears to be just a matter of time. The mystic planet, glowing red and ever brighter in the night skies, is heading toward its closest approach to the earth in 17 years this September, tantalizingly near and beckoning. After a hiatus of a dozen years, during which neither the U.S. nor the Soviet Union mounted missions to & Mars, a spacecraft is once again on its way, opening a new era in the exploration of the earth's closest planetary neighbor. During the next decade or so, the Soviets will launch a series of increasingly sophisticated unmanned Mars probes that they hope will culminate in a joint U.S.-Soviet manned mission to the Red Planet by the year 2010.

Last week that trip moved a step closer to reality. From its launching pad at the Baikonur space complex, near Tyuratam in the Soviet republic of Kazakhstan, a Proton rocket carrying an unmanned spacecraft rose on an orange and blue column of fire that illuminated the night sky. Turning lazily eastward, the rocket sent the craft off on an ambitious mission: to scout Mars and probe Phobos, one of its two tiny moons. Far below at the sprawling complex, technicians swarmed over a sister ship that is scheduled to be launched this week on a similar mission. Exulted Roald Sagdeyev, director of the Soviet Space Research Institute: "Now we can go and drink champagne!"

Even as the celebration went on, the thoughts of space experts turned to future Mars odysseys. Scientists and engineers in both the U.S. and the Soviet Union are involved in the design of complex unmanned craft that will travel to the planet. Some American scientists are even conducting tests on a model of the robotic vehicle that may one day rove the Martian surface. Others are considering the ships that will carry human crews to Mars, the orbiting space station needed to launch them, the size and safety of the crews and the most practical routes through space. Though some formidable problems remain, many Soviet and U.S. experts see no insurmountable obstacles to landing humans on Mars early in the 21st century.

While the American space program has been crippled since the Challenger disaster in January 1986, Soviet cosmonauts have been gaining invaluable experience aboard the orbiting Salyut and Mir space stations. And though U.S. astronauts are scheduled to return to space this September in the shuttle Discovery, which was wheeled to its Kennedy Space Center launching pad last week, NASA Administrator James Fletcher concedes that the Soviets are now "way ahead of us in manned flight." If each nation goes its own way, he predicts, the Soviets could land humans on Mars at least five years before the U.S. could.

Stifled by budget cuts and foundering without clear-cut goals, NASA has scheduled only one Mars probe, the Mars Observer, which will go into orbit around the planet in 1993 to collect data on climate and geology. And while President Reagan agreed at the recent Moscow summit to a cautious joint communique describing "scientific missions to the moon and Mars" as "areas of possible bilateral and international cooperation," the Administration has been at best lukewarm to the concept of exploring Mars, jointly or otherwise.

Among other Americans, however, the idea of a manned Mars mission is gaining momentum, despite the estimated $100 billion price tag for the undertaking. The venture has been endorsed by a dozen major publications, ranging from the New York Times to the New Republic. In a recent full-page advertisement in the Washington Post, the 125,000-member Planetary Society urged support for a manned mission. The ad listed the names of a glittering array of such prominent Americans as Walter Cronkite, Jimmy Carter, Utah Senator Jake Garn, Nobel Laureate Physicist Hans Bethe and Notre Dame's former president, the Rev. Theodore Hesburgh. All of them have signed the Society's "Mars Declaration," which advocates a U.S. space program that would lead to the human exploration of Mars.

In Congress, too, support is growing, despite strong opposition from those who fear that a manned Mars trip would soak up funds needed for social programs, unmanned scientific space probes and military projects, among other things. Democratic Senator Spark Matsunaga of Hawaii has even written a book, The Mars Project, that strongly advocates the space journey.

While the U.S. space program languishes, scientists from twelve European nations, the European Space Agency and the U.S. are participating in the Phobos mission, contributing technical expertise, instrumentation and onboard experiments to the Mars-bound ships. The U.S. is lending a hand with its superior Deep Space Tracking Network, which will aid the Soviets in navigating and keeping tabs on their craft. Another U.S. contribution, aboard one of the Phobos probes: a plaque honoring Astronomer Asaph Hall of the U.S. Naval Observatory, who in 1877 discovered Phobos and the other little Martian moon, Deimos (both named after the sons of the Greek god of war, and meaning fear and terror).

U.S. space watchers are impressed by the boldness, originality and scope of the Phobos operation. The twin Soviet probes will arrive at Mars in January 1989, easing into orbit about 4,000 miles above the planet's surface, or 140 miles higher than the orbit of Phobos. For four months the two probes will circle Mars in various orbits, peering down at possible future landing sites and using remote-sensing devices to investigate the landscape and weather.

Their scrutiny of Mars completed, first one probe and then the other will be sent by controllers to rendezvous with potato-shaped Phobos, which, like Deimos, is believed to be an errant asteroid that was captured by Martian gravity. Each craft, in turn, will descend as low as 100 ft. above Phobos. Maneuvering like cruise missiles, they will follow the contours of the landscape as their television cameras pick out surface features.

All the while, the versatile craft will be analyzing the composition of Phobos with two Buck Rogers-like devices. One, a laser beam only a millimeter in diameter, will vaporize first one spot and then another on the tiny moon, which is only 17 miles at its widest point, while an onboard instrument determines the chemical makeup of the vapor spewing up from each spot. Another beam consisting of krypton ions will bombard the moonlet, and an onboard mass spectrometer will identify the ions given off by the blasted surface materials.

Eventually each of the probes will release a lander that will rocket down onto the moonlet and shoot an attached "penetrator" into the surface as an anchor, essential because of the weak gravity (one-thousandth of the earth's gravitational pull). The solar-powered landers will then radio directly back to earth data on changes in the moon's gravitational field, thermal expansion and seismic noise. As if that were not enough, the frenetic probes will each drop a two-legged, domed "hopper" onto Phobos. After examining surface material and searching for magnetic fields at their landing sites, the hoppers will draw up spring-loaded, metal-alloy legs and, like giant frogs, leap about 20 yards to a new location, where the observations will be repeated. Each hopper is expected to make about ten leaps, reporting back each time by radio, until its battery runs out.

"These missions are novel and trail-blazing," says Cornell University Astronomer Carl Sagan, president of the Planetary Society and the man who first proposed a joint manned mission to Mars. "In terms of science, we'll all find out a lot about Phobos." Furthermore, he says, "in the long run, Phobos could act as a staging platform for human missions to Mars. It could also be a place where humans could live and work while they control robotic explorers on the surface of Mars."

Ever since they first peered into the night skies, humans have been awed and intrigued by Mars' baleful red glare. Ancient civilizations bestowed on the planet the name of their god of war. It was named Ares by the Greeks, Mars by the Romans. When the first telescopes revealed that the planets were neither specks of light nor gods but worlds, perhaps like earth, the notion grew that Mars might harbor life. Noting variations between the bright and dark areas of the planet, British Astronomer Sir William Herschel in 1784 attributed them to "clouds and vapors" and concluded that Mars had an atmosphere and that "its inhabitants probably enjoy a situation in many respects similar to our own."

German Mathematician Karl Gauss assumed that those inhabitants were intelligent. In 1820 he proposed growing a huge wheat field in Siberia in the form of a right triangle, surrounded by pine trees, that could be seen from afar. That would demonstrate to the Martians, Gauss figured, that earthlings not only existed but understood mathematics.

But was there any real evidence that Martians existed? After peering through his telescope in 1877, Italian Astronomer Giovanni Schiaparelli (an uncle of the celebrated Paris couturiere) reported that he had charted several dozen canali linking dark areas on the surface of Mars. These canali, the astronomer wrote, "present an indescribable simplicity and symmetry that cannot possibly be the work of chance."

No one was more excited by this revelation than a wealthy American mathematician, diplomat and astronomer, Percival Lowell of Boston, who established an observatory in Arizona and dedicated it to the study of Mars. By 1908, influenced in part by optical illusions and wishful thinking, Lowell had counted and named hundreds of canals, which he believed were part of a large network conveying water from the polar ice caps to the parched cities of an arid and dying planet. Lowell's observations and musings, in turn, inspired British novelist H.G. Wells to write The War of the Worlds, a dramatic account of an invasion of the earth by octopus-like Martians. In 1938 a radio adaptation of that novel by another man named Welles -- Orson, that is -- panicked many Americans who believed that a real Martian invasion was under way.

Even after the mighty 200-in. Mount Palomar telescope revealed no evidence at all of networks of straight lines or other manifestations of intelligent life on Mars, the fascination continued. Fredric Brown's novel Martians, Go Home, Ray Bradbury's The Martian Chronicles, Robert Heinlein's novel Stranger in a Strange Land, and the popular Buck Rogers comic strip all involved encounters with Martians of various sizes, shapes and consistencies.

Finally, in 1965, the triumphant mission of the U.S. spacecraft Mariner 4 brought some reality to musings about Mars. The craft flew past the planet at a distance of only 6,100 miles, transmitting 22 television pictures of a bleak, moonlike landscape, pockmarked by craters and showing no signs of life. Even so, hope persisted. To demonstrate that a Mariner flyby at a distance of thousands of miles might completely overlook a thriving civilization, a young and still unknown Carl Sagan that same year sifted through a thousand pictures of earth shot by a weather satellite orbiting only 300 miles up. In a paper entitled "Is There Life on Earth?" he reported that only one photograph, of a snow-covered superhighway cutting a straight line through a forest, showed any evidence of man's presence on this planet.

When Mariner 9 was successfully inserted into low orbit around Mars in 1971, a planet-wide dust storm obscured its vision for six weeks. After the dust settled, Mariner's cameras revealed a fascinating landscape: towering volcanoes, great canyons, lava flows and a multitude of craters in the red- hued plains. What excited scientists and Mars buffs the most, however, was the unmistakable traces of dry riverbeds and deltas etched into the rock, evidence that water had once flowed freely on the Martian surface. Had life evolved on Mars while water was still ample? And might living organisms still exist there, perhaps in microscopic form?

It was in part to answer such questions that the U.S. Viking 1 and 2 spacecraft, each consisting of an orbiter and a lander, were dispatched to Mars. When they arrived, 45 days apart, in 1976, cameras aboard the orbiters snapped away and remote-sensing devices searched for water vapor in the thin atmosphere and sought out frozen water in the polar ice caps. On the surface, the landers began providing the most accurate measurements yet of Martian surface temperatures, atmospheric density and wind velocity, while the cameras shot more than 4,500 spectacular close-up pictures of the surrounding, rock- strewn landscape. Each lander was also equipped with an arm that scooped up soil samples and fed them to a little onboard biological laboratory, where they were analyzed for any signs of metabolic activity, which would signify life.

; The first soil sample briefly breathed new life into the Mars mystique. After being moistened inside the lab, it suddenly released an unexpectedly high burst of oxygen, setting off a flurry of speculation among scientists on earth. Did the oxygen come from some tiny form of Martian life in the soil? After further tests failed to confirm those first results, scientists reluctantly concluded that the large amount of oxygen had probably been produced by a simple chemical reaction between water vapor and some unidentified oxygen-rich compound in the soil sample.

Some scientists, Soviet and American alike, have still not abandoned hope of finding life or its remnants deeper in the Martian soil. There life forms might have access to water and be protected from the fierce solar ultraviolet radiation that rains down on the surface, virtually unobstructed by the Martian atmosphere. Sedimentary rocks in the ancient riverbeds would be an ideal place to hunt for fossils of organisms that may have lived when Mars was more benign, with a thicker atmosphere, warmer climate and running water on its surface.

For these reasons alone, Mars enthusiasts say, further exploration of the Red Planet, both unmanned and manned, is scientifically justified. "There is a growing sense of purpose being attached to a manned flight to Mars, both in the Soviet Union and the U.S.," says Vyacheslav Balebanov, a deputy director of the Space Research Institute of the Soviet Academy of Sciences. Like most of his counterparts in the U.S., he would prefer a measured, logical, step-by- step program to a more hazardous, hastily mounted manned mission. "We must start to explore Mars in detail before such a flight is possible," he says.

That is just what the Soviets plan to do. In 1992, when America's Mars Observer is scheduled to fly, they hope to send a third Phobos spacecraft into Mars orbit carrying advanced remote-sensing devices, including a radar mapper that will seek out the best landing sites for future missions. Two years later, the Soviets intend to launch a pair of highly sophisticated landers to Mars. Each will carry a small computer-controlled surface rover, a six-wheeled vehicle capable of traveling as far as 60 miles from the lander. It will be equipped with TV cameras, scoops and drills to sample materials and a minilab to analyze them. With information gained from this mission, the Soviets hope to launch as early as 1998 a larger Mars lander-rover that could return soil samples to earth.

While the U.S. lacks a strong commitment to sending humans to Mars, the Administration's space policy, announced by President Reagan in February, does envision eventual "human exploration of the solar system." Toward that end, NASA has launched Project Pathfinder, a program to develop 18 new space technologies. They include compact nuclear reactors for powering lunar or Martian bases, in-space construction and assembly of spacecraft, and orbiting fuel depots for moon and Mars ships. "You can talk about going to Mars," says Pathfinder Leader Robert Rosen, "but you can't do it without these technologies." Congress appropriated $40 million for the project's first year.

Pathfinder did not start from scratch. NASA and the aerospace industry have long planned a variety of Mars missions that could lead to a manned flight. At NASA's Jet Propulsion Laboratory in Pasadena, Calif., scientists are designing an unmanned rover with six wheels, each more than 3 ft. in diameter, to accommodate the rocky Martian terrain. In a still unapproved mission, the rover, imbued with artificial intelligence and television eyes, would seek out appropriate rock samples and stow them in a craft designed to return them to earth for analysis. At NASA's Marshall Space Flight Center in Huntsville, Ala., experts are designing living quarters for the space station that the U.S. hopes to begin assembling in earth orbit in the mid-1990s. Plans call for private sleeping cubicles, each equipped with a TV, sound systems and a computer. Mars enthusiasts point out that approval of a manned Mars mission as a goal would finally provide a compelling rationale for the projected $30 billion space station that NASA has had trouble selling to a reluctant Congress. "The station would be needed to serve as an assembly point," says NASA's Brian Pritchard, who has studied the feasibility of such a plan. "We don't have the power to lift from 1 million to 3 million lbs. ((the weight of the Mars ship)) into orbit from the earth."

Why so huge a craft? In addition to carrying a million or more pounds of fuel, the ship must accommodate and sustain human beings for as long as three years. Just to exist in space for one day, for example, each crew member will require several pounds of oxygen, 4 lbs. of water and 3 lbs. of food. Consequently, for a crew of eight on a 900-day mission, a Mars spacecraft would have to carry as much as 40 tons of provisions alone. Any added weight would require using -- and carrying -- even more fuel, both for pulling away from the earth and launching from Mars for the return trip.

There is an alternative to a fully stocked larder: recycling, the recovery of water and oxygen from waste products. NASA has developed prototypes for reclaiming pure water from urine and wash water, and oxygen from the carbon dioxide exhaled by astronauts. For their part, the Soviets have been retrieving some of their water for years, condensing it from the exhaled, humid air in the spacecraft. But Arkadi Ushakov, of the Soviet Academy of Sciences, concedes that the recovery systems in use today cannot meet the demands of two- or three-year missions. He believes a Mars ship will have to contain its own biosphere of renewable plant and water resources.

Toward that goal, Soviet researchers are investigating natural recovery systems: plants that will not only serve as food but also, in the process of metabolizing, absorb carbon dioxide and produce oxygen. The best performers so far, Ushakov says, are traditional food plants like carrots, sugar beets and salad greens. At the Kennedy Space Center, NASA scientists are trying to develop what they call a "self-contained bioregenerative support system." It will include a chamber for growing plants; a food-processing module for extracting the maximum edible content from all plant parts; and waste management modules for capturing and recycling the solids, liquids and gases necessary to support life on a space journey.

In most of the manned Mars scenarios envisioned by NASA planners, the spacecraft would be constructed and fueled at a space station orbiting the earth at 17,500 m.p.h. Compared with blasting off from earth, considerably less fuel is needed to launch the craft from this speeding platform and boost it toward Mars at a velocity perhaps as great as 50,000 m.p.h. At that velocity, says Space Consultant and Author James Oberg, the "earth's gravity pulls on you a little, but it's like brushing your way through cobwebs." Following the path of the Hohmann ellipse,* the craft would coast in a leisurely course halfway around the sun, then begin to accelerate as it came under the gravitational sway of Mars.

To save fuel that would otherwise be used by firing retrorockets to ease the ship into orbit around Mars, the craft will be equipped with an aerobrake. This saucer-shaped structure, as large as 80 ft. in diameter, will slow the craft as it encounters the thin Martian atmosphere. A short burst from the rockets will then boost the craft just above the atmosphere and into orbit. From the orbiting craft, part of the crew will descend to the surface in a lander. After piling sand on the vehicle to shield it from the radiation that bombards the Martian surface, they will use the lander as a base for exploration.

How long the voyagers stay on Mars will depend in part on the homeward-bound route. To await the proper alignment of Mars and the earth for an economical Hohmann-ellipse return, the crew would have to remain on Mars for more than a year -- increasing the mission length to what now seems an unbearably long 1,100 days. But with the expenditure of more fuel, the explorers could blast off earlier, head toward Venus and loop around it, using the planet's gravity to whip their craft toward earth at a higher speed. That would cut the mission time to 600 to 700 days.

But the Venus route would also cause the craft to re-enter the earth's atmosphere at 80,000 m.p.h., in contrast to the returning Apollo's 25,000 m.p.h. "We're not sure we know how to build the appropriate heat shields," says Oberg. Also, at that speed, the astronauts would have a much smaller "window" for re-entering the atmosphere. "Come in too low, and you burn up," says Oberg. "Come in too high, and you overshoot. You miss the earth, and you'll never see it again." Other plans call for an unmanned cargo ship to precede the manned craft to Mars and for even higher velocities that would cut mission times down to a year.

Yet the problems of sending a spacecraft to Mars and bringing it back to earth pale when compared with the challenge of keeping its human cargo safe and in peak physical and mental condition. The medical consequences of long periods of weightlessness are still not fully understood. And radiation, says NASA's Michael Bungo, "is going to be a showstopper." Once beyond the earth's atmosphere and magnetic field, which protects terrestrial life from most lethal radiation, crew members would be vulnerable to cosmic rays. These highly energetic particles travel through space at close to the speed of light and can produce hazardous secondary radiation when they strike atoms in the aluminum walls of a spacecraft. During a single Mars mission, says Frank Sulzman, chief of NASA's space-medicine and biology branch, unprotected astronauts could receive an unacceptably high dose of radiation -- more than is now allowed workers in a lifetime on jobs that expose them to radioactivity.

Even more dangerous are solar flares, which usually blossom on the sun around the peak of the eleven-year solar cycle. During these massive explosions, which astronomers can spot in the form of extra-bright splotches suddenly appearing on the sun, bursts of X rays and charged particles are hurled outward at high velocities. Because protons from a large flare can easily penetrate the walls of a spacecraft and fatally riddle the body of an astronaut in half an hour, planners envision an onboard shelter into which the crew could repair as soon as a solar-flare warning was sounded. One idea is to build the shelter with the heavy-walled oxygen and water tanks that must be brought along anyway. Soviet scientists are experimenting with generating strong electrically charged fields around the spacecraft. These would have an effect similar to that of the earth's magnetic field, deflecting the speeding particles around the ship.

Another possible hazard on a long space journey has its source on planet earth: human nature. Soviet flights have demonstrated that performance levels begin to decrease as the days stretch into months. Cosmonaut Yuri Romanenko, whose 326 days aboard the space station Mir set a space endurance record last year, was down to only two hours of productive work a day toward the end of his eleven-month flight and had become decidedly peevish. "Leave me alone," he once snapped to mission control. "I have a lot of work to do."

Both American and Soviet behavioral scientists have begun to investigate small-group dynamics, which are likely to assume considerable significance during extended spaceflight. "There are always minor irritations involved in working with other people," says Psychologist Clay Foushee, of NASA's Ames Research Center. "Normally, these are not a problem because you can get up and move away. The trouble occurs when you can't leave a situation." That trouble can become catastrophic. Long Antarctic expeditions, which involve small groups isolated for months, have been marred by fights and occasional violence.

Other questions about group dynamics abound. Among the foremost: Should women be included on a Mars expedition? If so, what about sex? No one likes to talk publicly about that, admits NASA Flight Surgeon Patricia Santy. "There's no reason, even in a highly motivated professional crew, that the same kind of sexual tensions that develop here in offices aren't going to develop in space." Santy believes women should be included in the crew. If they are, she says, there should be at least two -- both for mutual support and to avoid disruptive sexual entanglements aloft. Former Astronaut Michael Collins has suggested an even simpler remedy: send up a crew of four married couples. "But eight is a bad number," he concedes, "because you want an odd number; in arguments, you don't want to risk a 4-to-4 tie vote."

For all the enthusiastic talk about a manned mission to Mars, many influential voices have been raised against it. None is more formidable than that of University of Iowa Physicist James Van Allen, the discoverer in 1958 of the earth-girdling radiation belts that today bear his name. With other scientists, he has long been critical of the shuttle, the space station and other programs that draw funds away from space science. "Any serious talk of a manned Mars mission at this time is grossly inappropriate," he says, arguing that the top priority of the U.S. should be to develop and build expendable rockets to launch satellites and space probes. "To talk about manned missions to Mars when we can't even launch a 500-lb. satellite is totally off the wall."

Van Allen believes a manned Mars mission would be "monstrously" expensive, further draining money from more economical unmanned scientific probes. The Mars mission does have a certain appeal, he concedes, because "it's a matter of high adventure. But if you want to put it on any practical basis, it's totally uncompetitive with unmanned spacecraft by a factor of ten."

The idea of a joint U.S.-Soviet Mars mission is galling to other Americans who, glasnost notwithstanding, simply do not trust the Soviets. Their view was summarized in a recent op-ed piece in the Los Angeles Times by Space Writer Alcestis Oberg, the wife of James Oberg. "A joint mission," she wrote, "completely and utterly ignores reality." Among the concerns raised by the proposed mission, she wrote, are the "potential for spying, for technology transfer, for interference in our political system, for the 'hostage holding' effect it would have on our space program and on our future." Her conclusion: "A complex, expensive, 25-year-long joint research program is like a marriage. It should be entered into soberly, advisedly, for better or for worse -- and only after a very long engagement during which trust is built and loyalty tested."

Even proponents believe the U.S. should approach a joint effort with the Soviets in gradual steps, perhaps starting with an unmanned mission to bring back soil samples from Mars in 1998. Many, like Sagan, are convinced that the advantages of a cooperative mission would override the possible risks. Besides sharply reducing the enormous costs of going to Mars alone, such a venture, says Sagan, "would revitalize a dispirited and unraveling NASA" and provide a "coherent focus for the U.S. space program."

Even more important, in his view, a joint mission might help draw the U.S. and the Soviet Union closer together. He dismisses fears that such a mission would risk giving away U.S. technology to the Soviets, pointing out that the Soviets are a decade ahead of the U.S. in several areas of spaceflight. "Technology transfer," Sagan concludes, "is likely to flow both ways."

The rising sentiment in the U.S. to return to space and eventually send men to Mars has not escaped the attention of politicians, including presidential candidates. Says Democratic Contender Michael Dukakis: "We should explore with the Soviet Union and other nations the feasibility and practicality of joint space-engineering activities that might pave the way to a joint manned mission to Mars." In a Huntsville, Ala., speech, Vice President George Bush urged a "long-term commitment to manned and unmanned exploration of the solar system. There is much to be done -- further exploration of the moon, a mission to Mars . . . "

If the U.S. is to mount or even play a meaningful role in a manned Mars mission early in the 21st century, the next President will have to make a commitment to a coherent national space policy sooner rather than later. Enormous problems remain to be solved, and two decades is precious little time for developing a program that would land humans on another planet. The clock is running, and to NASA Ames Scientist Carol Stoker, the message from the Soviets is coming across loud and clear: "We're going to Mars, and the bus is leaving." And like her, more and more Americans are asking: Will the U.S. be aboard?

FOOTNOTE: *The Hohmann ellipse is an ideal trajectory requiring a minimum of energy for a journey between any two planets, named after the German engineer who calculated it in 1925.