In NASA's dusty archives sit the remnants of a hidden space age, one whose ambition far exceeded that of the Apollo moon program. In the 1960s, NASA was eager to broaden its successes, and it began preparing—on paper, at least—for what it felt certain would be its next big step: a mission to Mars. To us, these plans, filed and half-forgotten, seem audacious enough to be the work of science fiction writers, yet the men who conceived them were conservative engineers.
Most proposed launching astronauts to Mars during the 1970s, soon after Apollo reached the moon. And most were only studies, intended to give engineers a grasp of the basic problems of Mars exploration rather than to map out an actual expedition. The detailed planning would start as soon as a president backed a Mars program.
That, of course, never happened. In the 1970s, NASA Mars studies went dormant as the agency marshalled its diminished resources to build the space shuttle. Near decade's end, Mars interest revived—outside NASA. The Planetary Society, a space advocacy group, sponsored the first major organized post-Apollo Mars study. Thereafter, privately funded enthusiasts continued to carry the torch. In 1981 the first "Case for Mars" conference, organized by students at the University of Colorado in Boulder, gave Mars planners their first public forum in a decade, and revealed the existence of a "Mars underground" of NASA scientists and engineers eager to look beyond the shuttle. (Five more "Case for Mars" studies followed until the Mars Society, which now conducts annual conferences, took over in 1996.)
Meanwhile, NASA briefly reentered the picture in the 1980s with several big but ineffectual reports that culminated in one proposal for a 30-year Mars program, part of the Space Exploration Initiative (SEI), a $250 to $500 billion program drawn up during the Reagan administration that drew little more than derision from Congress. It emerged at a time of record federal budge deficits and died quickly.
Still, sped along by the energy of the Mars underground and numerous Mars-minded societies and organizations, expedition planning has gained momentum in the last decade, both within NASA and without. Though NASA is not proposing a mission to Mars, engineers do know more about the planet and the effects of spaceflight on humans. SEI taught them that big programs don't sell anymore, so their plans are more realistic, less dependent on a national commitment to an Apollo-size program. Of the 1,000-plus manned Mars mission studies conducted by individuals, NASA, other government agencies, private companies, and educational institutions in the last 50 years, most of the ideas studied today were generated in the 1960s. Here we present six of NASA's most intriguing Mars planning efforts from that period—a time when slide rules ruled.
NASA's First Mars Expedition: 1961
In April 1959, engineers at NASA's Lewis Research Center in Cleveland astonished the Senate Committee on Aeronautical and Space Sciences by appealing for modest funds to study sending astronauts to Mars. NASA was but six months old. Project Mercury, the first U.S. piloted space project, was still two year from placing a human in space. But in fact, Lewis had begun research into propulsion for interplanetary journeys as early as 1957. The center studied advanced nuclear and ion propulsion systems, and saw Mars expedition planning as a natural extension of its work. Congress gave Lewis its money.
By the time Alan Shepard became the first American in space in May 1961, the center had laid out NASA's first Mars expedition plan. A report presented by Lewis engineers to the Institute of Aerospace Sciences in January 1960 described the plan: "The mission begins with the vehicle system in an orbit about the Earth...the vehicle is decelerated to establish an orbit about the planet...a Mars Landing Vehicle...descends to the Martian surface..." After a period of exploration, the lander launches and docks with the orbiting spacecraft, which then accelerates back to Earth. This remained the standard Mars blueprint until the early 1990s, when the agency began focusing on in-situ resource utilization, which allowed for lower departure masses and thus reduced the need for politically sensitive nuclear propulsion.
On May 25, 1961, President Kennedy set NASA's sights on the moon. Would-be Mars explorers saw it as a mixed blessing: On the one hand, many technologies needed for a piloted Mars flight could be developed along the way; on the other, concentrating on the moon might postpone serious Mars work.
Twirling Ion Ships to Mars: 1961
The large rocket engines for Apollo would be designed and tested at NASA's Marshall Space Flight Center in Huntsville, Alabama, where Wernher von Braun was director. When Lewis received its money for Mars work, Marshall was still a part of the Army Ballistic Missile Agency (ABMA), located at Redstone Arsenal.
Ernst Stuhlinger led advanced propulsion work at ABMA. He, like von Braun, was one of a few people who worked for both Adolf Hitler and Walt Disney. He spent World War II—with von Braun—designing and testing V-2 missiles at Peenemünde on the Baltic Sea. In 1945, the U.S. Army brought him to America along with dozens of his colleagues. In the late 1950s, Stuhlinger's ion-powered Mars armada starred in "Mars and Beyond," a Disney television episode.
Stuhlinger's ion drive used little propellant, cutting the number of expensive launches to assemble and fuel Mars vehicles. Because ion thrusters produce little acceleration, escaping Earth can take months. Once away from Earth, however, ion-powered spacecraft can eventually reach higher speeds than chemical- or nuclear-powered vessels. Stuhlinger's vehicles twirled to generate artificial gravity for their crews. Each ship's flat body was a radiator. Working fluid coursed through a nuclear reactor, which heated it; the reactor then drove a turbine to make electricity for ionizing—charging—and accelerating cesium propellant. The fluid passed through the radiator to cool down, then repeated the cycle.
Though NASA largely ignored ion drive, the Soviets based their Mars plans on it. The current NASA plan, which represents the work of numerous NASA centers, has a solar-powered ion "tug" boosting a chemical-fueled Mars vehicle to high-Earth departure orbit. This technique could cut the cost of a Mars expedition by half.
The EMPIRE Study: 1962-1964
According to author T.A. Heppenheimer, writing in NASA's newly published book The Space Shuttle Decision, von Braun realized that the Marshall center's role in Apollo would end as soon its large Saturn boosters were ready for moon flight. Unless NASA established some goal beyond Apollo, von Braun's center would face collapsing budgets and layoffs. Mars, some felt, might be the key to Marshall's future.
In mid-1962 Marshall launched the Early Manned Planetary Interplanetary Roundtrip Expeditions (EMPIRE) study. EMPIRE focused on Mars missions that could be made in the 1970s using modest extrapolation of Apollo technology. Mars landing missions were considered too ambitious, so the EMPIRE contractors—Lockheed, Ford Aeronutronic, and General Dynamics—were ordered to study easier manned Mars flyby and orbiter missions. However, Krafft Ehricke, director and principal author of the General Dynamics study, cheated—his EMPIRE Mars ships were good for both orbital and landing missions.
Ehricke, another Peenemünde veteran who later joined General Dynamics to help develop the Atlas missile, designed nuclear-powered EMPIRE spacecraft in two varieties—cargo and crew—intended to travel in convoys for safety. If a crew vehicle's engines became disabled, its crew module could move to a cargo vehicle so the expedition could be finished. The crew-carrying space craft tumbled end over end to create artificial gravity.
The General Dynamics scheme bears the unmistakable stamp of Ehricke. His study is immensely detailed—for example, it discusses such minutiae as in-flight exercise for the Mars crew—but a tad quirky. The in-flight exercise it recommends is table tennis.
Not to Be Left Out: 1963 and 1964
If Mars was to be NASA's target after the moon, no NASA center wanted to be excluded, so in 1963 several centers launched their own Mars studies. The earliest at Houston's Manned Spacecraft Center—known today as the Johnson Space Center—came under the supervision of MSC assistant director for engineering Maxime Faget, designer of the Mercury capsule. Faget believed Marshall's Mars enthusiasm was premature and scorned the rival center's focus on manned flybys. "The flyby mission will demand the least energy but will also have the least scientific value," he declared in 1962. He wanted a gradual approach to human spaceflight, with a space station and moon-base ahead of Mars flights. Robots could do flybys, he thought.
Despite this, MSC's first in-house Mars study used flyby techniques. Near Mars the crew entered a small lander and abandoned their flyby vehicle. They landed on Mars and explored the surface. An unmanned second flyby vehicle then flew past Mars, and the crew launched to meet it for the ride home to Earth. MSC's approach saved propellant—except for the small lander, at Mars. But the risks were significant: What if the lander missed its appointment with the second vehicle?
MSC also contracted with Ford Aeronutronic for the first detailed Mars lander study. For its design—a tub-shaped lifting body with twin winglets—Aeronutronic assumed that the Martian atmosphere was largely nitrogen, with a density that was 10 percent of Earth's sea level pressure. The astronauts would seek out Martian life. Among other things, they would study it for possible food value.
Mars Planning Moves to Washington: 1965-1967
It became apparent in July 1965 that Aeronutronic's lifting body design would have crashed on Mars—a radio experiment using the Mariner 4 robot flyby probe found that Mars' atmosphere is carbon dioxide with a density of less than one percent of Mars' atmosphere is carbon dioxide with a density of less than one percent of Earth's atmosphere. Mariner 4's effects on NASA's 1960s Mars plans cannot be overestimated. In addition to finding a painfully thin atmosphere, it snapped 21 pictures of moon-like craters containing no signs of life, edible or otherwise.
What's more, it showed that Faget was right. Robots could do flybys—no people were required. But the concept persisted. In 1966, Charles Townes, a Nobel laureate and head of the NASA Advisory Council, asked George Mueller, head of the Office of Manned Space Flight at NASA headquarters, to study a manned flyby mission. The task fell to Mueller's Planetary Joint Action Group (JAG), a NASA-wide team already in place to plan nuclear-powered Mars landing missions.
The JAG's manned flyby attempted to integrate humans and robots. The spacecraft would release a robot lander as it neared Mars. The lander would touch down, scoop a sample, then immediately lift off and return to the flyby craft. The astronauts would then study the sample for any life-forms mere minutes after it left Mars. A robot could, of course, launch a sample directly back to Earth—but would Martian life forms survive the long voyage?
In 1967, the Vietnam War's cost dominated the federal budget. Congress warned NASA that it would tolerate no new undertakings. Despite this, MSC incautiously called for industry bids to design the Mars sample retriever robot. Congress angrily quashed the effort and went one further—it killed a new robotic program called Voyager that would have sought evidence of life on Mars.
End of the Beginning: 1968 and 1969
More than any other individual, NASA Administrator James Webb was responsible for Apollo's success. An ingredient in that success was his refusal to discuss NASA's post-Apollo plans. He knew that NASA detractors might seize on them to the agency's detriment by allowing the to paint NASA as fiscally irresponsible. Washington-savvy Webb stepped down in 1969. Tom Paine, an entirely different kind of NASA chief, replaced him. Pain, a Washington neophyte with little grasp of politics, let vision be his guide as he set out to define NASA's post-Apollo goals. He liked the audacity of a plan that Mueller's office had outlined for NASA. Evolved from JAG work, Mueller's Integrated Program Plan saw a space base in Earth orbit, a moon base, and humans on Mars—all by 1982.
Central to the plan was a Mars spacecraft in the spirit of Star Trek's Enterprise or Discovery from the film 2001: A Space Odyssey. A nuclear-powered Mars cruiser designed by Boeing measured almost 500 feet long and 100 feet wide. Two of these behemoths would travel to Mars in tandem, each toting a North American Rockwell-designed Mars lander. With a cost of $29 billion—$200 billion in today's dollars—the scheme marked the giddy high-water mark of Mars expedition grandiosity.
In September 1969, President Nixon's Space Task Group endorsed the NASA plan, but with reservations. NASA formed an agency-wide team to begin implementation. But Nixon ignored the task group's recommendations, opting instead to funnel NASA's budget toward building the space shuttle. In 1971 NASA ceased all manned Mars flight planning. According to some old hands, mere mention of Mars within NASA became verboten—the barely affordable shuttle was a target of frequent attacks, so one can only imagine how people would react to Mars.
After it fell afoul of Mueller's JAG efforts, the Voyager program reemerged as Viking, a probe that landed on Mars in 1976. Viking's life hunt yielded equivocal results, but other experiments hinted at a Mars with a complex Earth-like past and useful resources. The Viking results helped trigger a revival of Mars planning in the 1980s, an provided data for the central cost-saving technique in the current Mars plan—use of native resources to make rocket fuel. The name "Voyager" was re-applied to a program of outer planet exploration. Faget supervised design of the space shuttle, then retired near Houston. Paine left NASA in 1970. In 1985, the Reagan administration called upon him to chart NASA's future course a second time as head of the National Commission on Space, then, following the 1986 Challenger accident, quietly shelved his audacious vision of American settlements on the moon and Mars. He passed away in 1992.