Von Braun's Mars pitch to the STG (1969)

On August 4, 1969, NASA Marshall Space Flight Center director Wernher von Braun (bottom image above) gave a 30-minute presentation to the Space Task Group (STG), a body created by President Richard M. Nixon in February 1969 to chart NASA's future in space. The presentation formed the heart of the space agency's 45-minute pitch to the STG that day. In retrospect, it also marked the apogee of von Braun's career. When the German-born rocketeer offered his vision of human Mars flight in the 1980s, it was still just barely possible to believe that the spaceflight salesmanship for which he was famous could help to shape the future of American spaceflight, just as it had in the previous two decades.

Von Braun proposed a series of Mars program development milestones for the 1970s. The decade would begin with a presidential decision to proceed with the development of a flight-worthy NERVA nuclear rocket engine. The next year, NASA would receive the go-ahead to develop a reusable Space Shuttle for launching crews and cargoes from Earth to orbit, and a Mission Module that would serve as the basis for Earth-orbiting space station modules and Mars ship crew modules. In 1973, NASA would receive authorization to develop the NERVA-equipped Nuclear Shuttle.

The NERVA engine, winged reusable Earth-to-orbit Space Shuttle, multi-role Mission Module, and Nuclear Shuttle were all components of NASA's Integrated Program Plan, which emphasized astronaut activities in Earth-moon space (for example, at a lunar surface base). None of these hardware elements were specific to the Mars program. Approval of Mars Excursion Module (MEM) development in 1974 would, thus, mark the nation's first clear commitment to humans on Mars. The MEM would constitute the only major piece of spaceflight hardware in von Braun's plan that was only applicable to Mars flight.

The year 1975 would see the first flight of the reusable Earth-to-orbit Space Shuttle and the first space station based on the common Mission Module design. The latter would reach orbit atop an upgraded Saturn V rocket. NASA's budget would peak at about $7 billion per year, or about 0.6% of U.S. Gross National Product.

The following year, NASA would receive the go-ahead to develop automated Mars Sample Return Probes that would be carried on board the Mars ship. In 1977, the space agency would conduct the first Nuclear Shuttle and first planetary Mission Module tests. Then, in 1978, the MEM would be tested in Earth orbit. A Sample Return Probe test in 1979 would round out NASA's decade of Mars mission development.

Von Braun had the first manned Mars mission departing Earth orbit during the minimum-energy Earth-Mars transfer opportunity in 1981. Each Mars mission would employ two identical six-man spacecraft comprising at Earth-orbit departure three Nuclear Shuttles and a Mission Module. An unpressurized forward compartment would house the two-stage conical MEM, an airlock for spacewalks, six Mars Sample Return Probes, and two Venus probes. The compartment would measure 33 feet in diameter while the MEM would measure 30 feet across its bowl-shaped heat shield.

The four-deck Mission Module would contain quarters for six people, but could support the entire 12-man expedition crew complement in an emergency. Measuring 22 feet in diameter and 110 feet long, it would also include labs, the spacecraft control center, and a radiation shelter. A sterilized, isolated bio-lab for handling Mars surface samples would be mounted below the Mission Module's lowermost deck.

A docking mechanism would link the Mission Module to the front of the center Nuclear Shuttle. Two other Nuclear Shuttles would be attached to the center Nuclear Shuttle's sides. Each would measure 33 feet in diameter by 160 feet long. At Earth-orbit departure, the complete spacecraft would measure 100 feet across the three Nuclear Shuttles and 270 feet long.

For reasons of economy, von Braun proposed that the port and starboard Nuclear Shuttles for each spacecraft be drawn from the fleet of Nuclear Shuttles routinely used for lunar base resupply and other Integrated Program Plan missions. The Mission Module, center Nuclear Shuttle, and MEM, for their part, would be built new for each Mars spacecraft. All new hardware would reach assembly orbit on upgraded Saturn V rockets. Space Shuttles would launch water, food, some propellant, and astronauts to the Mars ships; then, on November 12, 1981, the voyage to Mars would begin.

At launch from Earth orbit, each Mars ship would have a mass of 1.6 million pounds, of which 75% would be liquid hydrogen propellant. The port and starboard Nuclear Shuttles would fire first. Once Trans-Mars Injection was achieved, they would shut down, separate from the center Nuclear Shuttle and Mission Module, turn around, and fire their engines again to slow down and enter an elliptical Earth orbit. A few days later, they would reach perigee at the original assembly orbit altitude, fire their engines to circularize their orbit, and rendezvous with the Space Station for refurbishment and reuse. The Mars ships would each mass 675,000 pounds after port and starboard Nuclear Shuttle separation.

Von Braun assured the STG that the nine-month coast to Mars would be "by no means an idle phase" for the astronauts. The ships would each serve as "a manned laboratory in space, free of the disturbing influences of the Earth. The fact that there will be two observation points, Earth and spacecraft, permits several possible experiments." He added that "as yet unidentified comets might be observed for the first time."

On August 9, 1982, the twin ships would fire their NERVA engines to slow themselves so that Mars' gravity could capture them into an elliptical orbit about the planet. An elliptical orbit, von Braun explained, would require less propellant to enter and depart than a circular one. Spacecraft mass at Mars orbit insertion would be 650,000 pounds.

For two days the crews would observe Mars to select landing sites for the expedition's 12 automated Mars Sample Return Probes. These would land, retrieve samples uncontaminated by human contact, and lift off to deliver the samples automatically to the sterilized bio-labs on the Mars ships for study.

If the samples were found to contain no hazards, one of the expedition's twin 95,000-pound MEMs would descend to the surface carrying three astronauts. Von Braun promised the STG that "Man's first step on Mars will be no less exciting than Neil Armstrong's first step on the moon." Apollo 11 commander Armstrong had set foot on the moon just two weeks before von Braun's STG pitch (July 20, 1969). The timing of his presentation was not accidental; NASA Administrator Thomas Paine sought to exploit the excitement Apollo 11 had generated to obtain the STG's endorsement of a manned Mars program in its report to Nixon.

The astronauts would spend from 30 to 60 days exploring Mars. Von Braun's list of probable objectives for the manned Mars exploration included understanding
martian geology, the search for life, and prospecting for resources, such as water, which could provide the raw material for Earth-return rocket propellants on future Mars expeditions.

After completing their exploration tasks, the landing party would lift off in the MEM ascent stage using the descent stage as a launch pad. In the event of trouble, the second MEM would come into play: "capability is provided," von Braun explained, "for one man to land a MEM and bring a stranded crew back to the ship." The MEM ascent stage would dock with the orbiting ship and the crew would transfer up to 900 pounds of film, equipment, and Mars samples before casting it off.

After 80 days at Mars, the twin Mars ships would fire their center Nuclear Shuttles near periapsis (low point) in their orbit to begin the voyage home to Earth. Each spacecraft would have a mass prior to Mars orbit departure of 380,000 pounds.

On February 28, 1983, the expedition spacecraft would use fly past Venus to use its gravity to slow their approach to Earth. This detour, von Braun explained, would trim the amount of propellant the ships would need to slow down and capture into Earth orbit. During the Venus swingby, the astronauts would use radar to map the planet's cloud-covered surface and would deploy a total of four automated probes into its atmosphere.

Return to Earth would occur on August 14, 1983, a little more than 14 years after von Braun's presentation to the STG. He noted that an Apollo-style direct reentry into Earth's atmosphere would be possible; until, however, "a better assessment can be made of the back contamination hazard (the return by man of pathogens that might prove harmful to earth inhabitants), a more conservative approach has been planned, i.e., the return of the crew to earth orbit for a quarantine period." The Nuclear Shuttle would place the Mission Module into Earth orbit and complete a rendezvous with the Space Station, where doctors would examine the astronauts.

The spacecraft would each have a mass of 160,000 pounds at mission's end (that is, one-tenth of its Earth departure mass). The crew would return to Earth on board a Space Shuttle, and the Nuclear Shuttles would be refurbished and re-used.

Von Braun concluded his presentation by discussing how the Mars program would provide a culmination for NASA's Integrated Program Plan. Additional Mars expeditions would occur in 1983-1984, 1986-1987, and 1988-1989. NASA would establish a 50-person Mars Base in 1989, in time for the 20th anniversary of his presentation. By that time, NASA's annual dollar outlay would stand at $5 billion and its share of Gross National Product would have declined to 0.3%, assuming a steady 4% per year growth in the national economy.

"Manned Mars Landing Presentation to the Space Task Group," Wernher von Braun, presentation materials, August 4, 1969.