List of crewed Mars mission plans

This list of crewed Mars mission plans is a listing of concept studies for a crewed mission to Mars during the 20th and 21st centuries. It is limited to studies done with engineering and scientific knowledge about the capabilities of current/latest technology then, typically for high-budget space agencies like NASA. Mission profiles include crewed flybys, crewed landers, or other types of Mars system encounter strategies.

Concepts Many mission concepts for expeditions to Mars have been proposed since the late 20th century, and they have had to take into account Mars' unique properties. The timing of these missions rely on Earth's and Mars' orbits: every 26 Earth months, the Earth-to-Mars transfer energy reaches a minimum, so missions typically coincide with one of these windows Notably, the Mariner 4 Mars flyby in 1965 provided radically more accurate data about the planet: a surface atmospheric pressure of about 1% of Earth's and daytime temperatures of −100 degrees Celsius (−148 degrees Fahrenheit) were estimated. No significant magnetic field or Martian radiation belts were detected. The new data meant redesigns for planned Martian landers, and showed life would have a more difficult time surviving there than previously anticipated. Later NASA probes in the 1970s, 1980s, and 1990s confirmed the findings about Mars environmental conditions. The first engineering analysis of a crewed mission to Mars was made by Wernher von Braun in 1948. It was originally published as Das Marsprojekt in West Germany in 1952, and as The Mars Project in English in the United States in 1953. Von Braun's Mars "flotilla" included ten 4,000-ton ships with 70 crew members. The expected launch year was 1965.

List The list is in semi-chronological order, with some groupings, as variation can exist in the dating of a given plan. Various references were consulted. LEO mass refers to how much hardware must be put in low Earth orbit for the mission. For comparison, the low Earth orbit payload capacity per launch of the U.S. Space Shuttle is about 25 metric tons, and that of the Saturn V, 120 metric tons.

Mission proposals

20th century

Over the last century, a number of mission concepts for such an expedition have been proposed. David Portree's history volume Humans to Mars: Fifty Years of Mission Planning, 1950–2000 discusses many of these.

Wernher von Braun proposal (1947 through 1950s) Wernher von Braun was the first person to make a detailed technical study of a Mars mission. Details were published in his book Das Marsprojekt (1952, published in English as The Mars Project in 1962) and several subsequent works. Willy Ley popularized a similar mission in English in the book The Conquest of Space (1949), featuring illustrations by Chesley Bonestell. Von Braun's Mars project envisioned nearly a thousand three-stage vehicles launching from Earth to ferry parts for the Mars mission to be constructed at a space station in Earth orbit. The mission itself featured a fleet of ten spacecraft with a combined crew of 70 heading to Mars, bringing three winged surface excursion ships that would land horizontally on the surface of Mars. (Winged landing was considered possible because at the time of his proposal, the Martian atmosphere was believed to be much denser than was later found to be the case.) In the 1956 revised vision of the Mars Project plan, published in the book The Exploration of Mars by Wernher Von Braun and Willy Ley, the size of the mission was trimmed, requiring only 400 launches to put together two ships, still carrying a winged landing vehicle. Later versions of the mission proposal, featured in the Disney "Man In Space" film series, showed nuclear-powered ion-propulsion vehicles for the interplanetary cruise.

U.S. proposals (1950s to 1970s)

From 1957 to 1965, work was done by General Atomics on Project Orion, a proposal for a nuclear pulse propulsion spacecraft. Orion was intended to have the ability to transport extremely large payloads compared to chemical rocketry, making crewed missions to Mars and the outer planets feasible. One of the early vehicle designs was intended to send an 800-ton payload to Mars orbit. The Partial Nuclear Test Ban Treaty of 1963 made further development unviable, and work ended in 1965. In 1962, Aeronutronic Ford, General Dynamics and the Lockheed Missiles and Space Company made studies of Mars mission designs as part of NASA Marshall Spaceflight Center's "Project EMPIRE". These studies indicated that a Mars mission (possibly including a Mercury and Venus fly-by) could be done with a launch of eight Saturn V boosters and assembly in low Earth orbit, or possibly with a single launch of a hypothetical "post Saturn" heavy-lift vehicle. Although the EMPIRE missions were never proposed for funding, they were the first detailed analyses of what it would take to accomplish a human voyage to Mars using data from actual NASA spaceflight, laying the basis for future studies, including significant mission studies by TRW, North American, Philco, Lockheed, Douglas, and General Dynamics, along with several in-house NASA studies. Following the success of the Apollo Program, von Braun advocated a crewed mission to Mars as a focus for NASA's crewed space program. Von Braun's proposal used Saturn V boosters to launch NERVA-powered upper stages that would propel two six-crew spacecraft on a dual mission in the early 1980s. The proposal was considered by President Richard Nixon, but passed over in favor of the Space Shuttle. In 1975, von Braun discussed the mission architecture that emerged from these Apollo-era studies in a recorded lecture, and while doing so suggested that multiple shuttle launches could instead be configured to lift the two nuclear thermal rocket engine-equipped spacecraft in smaller parts, for assembly in orbit.

Soviet mission proposals (1956 through 1969)

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