Early Mission Planning

In 1952, Dr. Wernher von Braun[36] published the first detailed mission architec­ture for human exploration of the red planet in his classic book, The Mars Project. The manuscript was actually the appendix of an earlier, unpublished work that von Braun had written while interned with his fellow German rocket engineers in El Paso, Texas after the conclusion of World War II (WW1I). Von Braun had a sweeping vision for human travel to Mars. His plan called for ten 400-ton space­craft capable of transporting a crew of 70 to the red planet—almost 1,000 ferry flights would be required to assemble this massive “flotilla” in Earth orbit. The strat­egy incorporated a minimum-energy trajectory that would carry the ships to Mars in approximately eight months. Upon arriving in Martian orbit, a glider would descend for a sliding landing on one of the planets polar ice caps. The crew from that ship would then trek 4,000 miles to the equator to build a landing strip for two additional gliders, which would transport the remainder of the exploratory team to the surface. After setting up an inflatable base camp habitat, the crew would com­mence a 400-day survey of the planet—which, von Braun assumed, would include taking samples of local flora and fauna and exploring the Martian canals—this was more than a decade before Mariner 4 returned the first close-up images of Mars back to Earth. Following a year of exploration, the crew would return to Earth,

Early Mission Planning

These paintings by Chesley Bonestell illustrate von Brauns plan for human exploration of Mars, from construction of the spaceships in Earth orbit, to entering Mars orbit, to exploring the surface itself (Courtesy Chesley Bonestell archives)

completing its three-year journey.[37]

In the early 1950s, Collier’s magazine approached Wernher von Braun and sev­eral other prominent engineers and scientists with an offer to write a series of eight articles about space exploration. The publication of these articles in Collier’s, with its circulation of almost four million, represented the beginning of a concerted “soft­ening up” process for space exploration in general, and Moon and Mars explora­tion in particular—with the express purpose of educating the American public.[38] In April 1954, von Braun and journalist Cornelius Ryan penned an article for Collier’s entitled “Can We Get to Mars?” This piece drew heavily from the mission concept found in The Mars Project, but also included an Earth-orbiting space station that would be used during the projects construction phase. In addition, Von Braun included a discussion that analyzed the potential physical and psychological dif­ficulties that the astronaut crew would face on the voyage. He concluded, “…we have, or will acquire, the basic knowledge to solve all the physical problems of a flight to Mars… [but] psychologists undoubtedly will [have] to make careful plans to keep up the morale of the voyagers.” In 1956, von Braun collaborated with fellow German engineer Willy Ley to expand on the Collier’s articles in a book entitled The

Exploration of Mars. The manuscript introduced a refined, cheaper mission architec­ture that reduced the number of ships going to Mars from 10 to 2, and the number of crew from 70 to 12.[39]

In the mid-1950s, the Collier’s articles served as the basis for three animated films about space exploration produced by Walt Disney. Wernher von Braun served as technical advisor for the shows, while Disney provided artistic direction for the series. The American Broadcasting Company aired the first episode entitled “Man in Space” on 9 April 1955- Disney, introducing the broadcast, stated that the aim of the series was to merge “the tools of our trade with the knowledge of the scientists to give a factual picture of the latest plans for man’s newest adventure.” The epi­sode introduced fundamental scientific principles and concluded with von Braun’s vision for a four-stage orbital rocket ship. The second show, entitled “Man and the Moon,” aired on 28 December 1955 and “present[ed] a realistic and believable trip to the moon in a rocket ship—not in some far-off fantastic never-never land, but in the near foreseeable future.” The final show in the series, entitled “Mars and Beyond,” aired almost two years later on 4 December 1957- During this episode, von Braun and Dr. Ernst Stuhlinger revealed plans for “atomic electric space ships [that] feature [d] a revolutionary new principle that will make possible the long trip to Mars with only a small expenditure of fuel.” The Disney technicians provided dramatic animations of a 13-month voyage employing these nuclear rocket engines. TV Guide stated that “Mars and Beyond” represented “the thinking of the best sci­entific minds working on space projects today, making the picture more fact than fantasy.”[40]

Howard McCurdy argues in his book Space and the American Imagination that von Braun’s collaborations with Collier’s and Disney were part of a larger concerted effort to prepare the public for the inevitable conquest of space. He contends that scientists, writers, and political leaders sought to construct a romantic vision of space exploration laid upon images already rooted in the American culture, such as the myth of the frontier. The resulting vision of space exploration had the power to excite, entertain, or frighten (i. e. Cold War)—and it was incredibly successful. In 1949, only 15% of the population believed that we would go to the moon in the 20th century. By the time President Kennedy announced the lunar landing goal, however, the majority of Americans viewed it as inevitable. McCurdy asserts that the primary reason for this shift in national mood was the introduction of space concepts to the mainstream public by von Braun and other visionaries during the 1950s.[41]

Building on the clear rise in interest in space exploration following the launch of Sputnik (and solidified with President Kennedy’s decision to send humans to the Moon), NASA began a series of studies to investigate alternative mission profiles for sending humans to Mars—continuing the softening up process that Wernher von Braun had initiated in the early 1950s and beginning a long-term alternative gen­eration process within the policy stream. In April 1959, Congress approved funding for NASA Lewis Research Center in Cleveland, Ohio to conduct the first official architecture study for human exploration of Mars. Under the Lewis plan, a crew of seven would be propelled toward the red planet by an advanced, high-thrust nuclear rocket engine. The strategy called for a 420-day round trip with a 40-day surface stay. The ship design provided substantial living space for the crew and a heavily shielded cylindrical vault in the hub to protect the crew from radiation exposure. This basic model, using nuclear propulsion for the Earth orbit to Mars journey, became the standard within NASA for the next decade.[42]

In 1961, the year in which humans first reached Earth orbit, NASA was largely focused on mission plans for sending humans to explore the surface of the moon— not Mars. However, there was at least one important study of Mars exploration that was produced that year. Authored by Ernst Stuhlinger, who directed advanced propulsion work at Marshall Space Flight Center (MSFC), the study expanded on earlier designs for ion-powered spacecraft. This form of propulsion used an electric current to convert a propellants (e. g. cesium) atoms into positive ions. The engine would then expel these high-speed ions to create a constant low-thrust acceleration. The primary benefit of this vehicle type was that it used relatively little propellant, drastically reducing the amount of launches required to assemble a ship in Earth – orbit. The main drawback, however, was that the low-thrust vehicle would take longer to make the trip to Mars and back. Stuhlinger also introduced a new inno­vation, twirling the spacecraft to generate artificial gravity for the crew. His overall mission plan called for five 150-meter long twirling ion ships to take 15 astronauts on the voyage to the red planet.[43]

In mid-1962, MSFC commenced the Early Manned Planetary Roundtrip Expe­ditions (EMPIRE) study. Wernher von Braun, now director of Marshall Space Flight Center (MSFC) and the leading advocate pushing for exploration of Mars, recog­nized that his field center would need a post-Apollo goal if it were to survive after completion of the Saturn V rocket program. The goal of the EMPIRE study was to provide a long-term human exploration strategy. The study participants were tasked with creating mission plans that utilized moderate modifications of Apollo tech – nology for Martian flyby and orbiter (but not landing) missions. Three EMPIRE contractors submitted reports to MSFC—Lockheed, Ford Aeronutronic, and Gen­eral Dynamics. The Lockheed and Aeronutronic teams focused primarily on 18 to 22 month flyby missions conducted by spacecraft that utilized a rotating design to create artificial gravity for the crew. The General Dynamics report, on the other hand, focused on orbiter missions conducted by convoys of modular spacecraft. Krafft Ehricke, the principal author of the General Dynamics study, also included options for landing missions. All of the missions proposed under the auspices of the EMPIRE study required launch vehicles capable of lifting 2 Vi to 5 times the weight of the Saturn V being developed for Project Apollo.[44] [45]

In 1963, at the same time MSFC was conducting the EMPIRE study, the Manned Spacecraft Center (MSC) (later renamed the Johnson Space Center—JSC) started to conduct its own advanced planning for the future of the space program. Assistant Director of MSC, Maxime Faget, favored a phased exploration approach, with a space station and lunar base preceding a human mission to Mars. The MSC study produced the first detailed designs for a Mars Excursion Module (MEM), a piloted craft that would be capable of landing on the Martian surface. The mis­sion plan developed by MSC called for a complicated flyby-rendezvous where two separate spacecraft would be sent toward Mars—Direct and Flyby. The Flyby ship would depart Earth on a 200-day trip to Mars. The piloted Direct ship would leave 50 to 100 days later on a 120-day trip to Mars. Upon arrival, the Direct ship would release the MEM, which would land on the red planet. After completing its mis­sion, the MEM would rendezvous with the Flyby ship as it swung past Mars and headed home. This high-risk approach saved propellant because it utilized a free return trajectory to return the MEM to Earth.11

In July 1965, Mariner 4 conducted the first flyby of Mars and snapped its historic 21 images of the red planet. The photographs revealed a planet with an exceptionally thin carbon dioxide atmosphere and an apparently lifeless, cratered landscape. These findings had a dramatic impact on planning for planetary explora­

tion. Researchers had always assumed Mars to be an Earthlike planet that would support a human crew. Instead they found a resoundingly hostile environment. As a result, the next major Mars study, conducted the following year by the Office of Manned Spaceflight at NASA Headquarters, called for humans to orbit the planet but counted on robotic landers to conduct actual surface exploration. By 1967, with the Vietnam War heating up, Congress eliminated all funding for studying human exploration of the red planet.[46]