Human mission to Mars

Artist's conception of a human mission on the surface of Mars

A human mission to Mars (sometimes, "manned" mission to Mars) refers to humans going to the planet Mars, including orbiting Mars, landing on the surface, or walking on the surface. ,jblkvblabvlxvlvlskbvkb

Challenges

There are several key challenges that a human mission to Mars must overcome:

1. physical effects of exposure to high-energy cosmic rays and other ionizing radiation
2. physical effects of a prolonged low-gravity environment
3. psychological effects of isolation from Earth
4. social effects of several humans living under crowded conditions for over one earth year
5. inaccessibility of terrestrial medical facilities

Some of these issues were estimated statistically in the HUMEX study. Ehlmann and others have reviewed political and economic concerns, as well as technological and biological feasibility aspects.

While fuel for roundtrip travel could be a challenge, methane and oxygen can be produced utilizing Martian H₂O (preferably as water ice instead of chemically bound water) and atmospheric CO₂ with mature technology.

Proposals

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 (1962) and several subsequent works,, and featured in Collier's magazine in a series of articles beginning March 1952. A variant of the Von Braun mission concept was popularized in English by Willy Ley 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 heading to Mars, each one carrrying 70 people, 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 more dense 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 vehicles. 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 and 1960s)

Artist's depiction of Mars Excursion Module landed on Mars, from a 1963 NASA study

Eugene F. Lally of Caltech for NASA's Jet Propulsion Laboratory designed manned Mars missions and presented them at American Rocket Society conventions as early as 1959. In another paper Lally proposed a simulated gravity concept that would protect the astronauts during the prolonged weightlessness of the flight to Mars. The paper titled "To Spin or Not to Spin" proposed separating two main segments of the spacecraft connected by cables and spun up to simulate gravity. In the center of rotation Lally placed an all-optical guidance module to provide real time onboard navigation to the astronauts, this paper was titled "Mosaic Guidance for Interplanetary Travel" 1961.

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 "Project EMPIRE". These studies indicated that a Mars mission (possibly including a 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 only studies, and never proposed as funded projects, these were the first detailed analyses of what it would take to accomplish a human voyage to Mars using data from the actual NASA spaceflight, and laid much of 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 manned mission to Mars as a focus for NASAs manned space program. Von Braun's proposal used Saturn V boosters to launch nuclear-powered (NERVA) upper stages that would power two six-crew spacecraft on a dual mission in the early 1980s. The proposal was considered by (then president) Richard Nixon but passed over in favor of the Space Shuttle.

Soviet mission proposals (1956 through 1970)

Main article: Martian Piloted Complex

Main article: TMK

The Martian Piloted Complex or "'MPK'" was the a proposal by Mikhail Tikhonravov of the Soviet Union for a manned Mars expedition, using the (then proposed) N-1 rocket, in studies from 1956 to 1962.

Artist's depiction of TMK-MAVR

Heavy Piloted Interplanetary Spacecraft (known by the Russian acronym TMK) was the designation of a Soviet Union space exploration proposal in the 1960s to send a manned flight to Mars and Venus (TMK-MAVR design) without landing. The TMK spacecraft was due to launched in 1971 and make a three-year long flight including a Mars fly-by at which time probes would have been dropped. The TMK project was planned as an answer from the Soviet Union to the United States manned moon landings. The project was never completed because the required N1 rocket never flew successfully.

The Mars Expeditionary Complex, or "'MEK"' (1969) was another Soviet proposal for a Mars expedition that would take a crew from three to six to Mars and back with a total mission duration of 630 days.

Case for Mars (1981-1996)

Following the Viking missions to Mars, between 1981 and 1996 a series of conferences named The Case for Mars were held at the University of Colorado at Boulder. These conferences advocated human exploration of Mars, presented concepts and technologies, and held a series of workshops to develop a baseline concept for the mission. The baseline concept was notable in that it proposed use of In Situ Resource Utilization to manufacture rocket propellant for the return trip using the resources of Mars. The mission study was published in a series of proceedings volumes published by the American Astronautical Society. Later conferences in the series presented a number of alternative concepts, including the "Mars Direct" concept of Robert Zubrin and David Baker; the "Footsteps to Mars" proposal of Geoffrey A. Landis, which proposed intermediate steps before the landing on Mars, including human missions to Phobos; and the "Great Exploration" proposal from Lawrence Livermore National Laboratory, among others.

NASA Space Exploration Initiative (1989)

Main article: Space Exploration Initiative

In response to a presidential initiative, NASA made a study of a project for human lunar- and Mars exploration as a proposed follow-on to the International Space Station project. This resulted in a report, called the 90-day study, in which the agency proposed a long-term plan consisting of completing Space Station as "a critical next step in all our space endeavors," returning to the moon and establishing a permanent base, and then sending astronauts to Mars. This report was widely criticized as too elaborate and expensive, and all funding for human exploration beyond Earth orbit was canceled by Congress.

Mars Direct (early 1990s)

Main article: Mars Direct

Because of the distance between Mars and Earth, the Mars mission would be much more risky and more expensive than past manned flights to the Moon. Supplies and fuel would have to be prepared for a 2-3 year round trip and the spacecraft would have to be designed with at least partial shielding from intense solar radiation. A 1990 paper by Robert Zubrin and David A. Baker, then of Martin Marietta, proposed reducing the mission mass (and hence the cost) with a mission conceptual design using In Situ Resource Utilization to manufacture propellant from the Martian Atmosphere. This proposal drew on a number of concepts developed by the former "Case for Mars" conference series. Over the next decade, this proposal was developed by Zubrin into a mission concept, Mars Direct, which he developed in a book, The Case for Mars (1996). The mission is advocated by the Mars Society as a practical and affordable plan for a manned Mars mission.

NASA Design reference mission (late 1990s)

Main article: Design reference mission 3.0

File:Mars design reference mission 3.0 image 1.jpg

Mars design reference mission 3.0

In the mid to late 1990s NASA developed several conceptual level human Mars exploration architectures. One of the most notable and often quoted was the NASA Design reference mission 3.0 (DRM 3.0). The study was performed by the NASA Mars Exploration Team at the NASA's Johnson Space Center (JSC) in the 1990s. Personnel representing several NASA field centers formulated a “Reference Mission” addressing human exploration of Mars. The plan describes the first human missions to Mars with concept of operations and technologies to be used as a first cut at an architecture. The architecture for the Mars Reference Mission builds on previous work, principally on the work of the Synthesis Group (1991) and Zubrin’s (1991) concepts for the use of propellants derived from the Martian atmosphere. The primary purpose of the Reference Mission was to stimulate further thought and development of alternative approaches, which can improve effectiveness, reduce risks, and reduce cost. Improvements can be made at several levels; for example, in the architectural, mission, and system levels.

Vision for Space Exploration (2004)

Main article: Vision for Space Exploration

United States President George W. Bush announced an initiative of manned space exploration on January 14, 2004, known as the Vision for Space Exploration. It includes developing preliminary plans for a lunar outpost by 2012 and establishing an outpost by 2020. Precursor missions that would help develop the needed technology during the 2010-2020 decade were tentatively outlined by Adringa and others. On Sep 24 2007, Michael Griffin, the NASA administrator, hinted that NASA may be able to launch a human mission to Mars by 2037. The needed funds are to be generated by diverting $11 billion from space science missions to the vision for human exploration.

Aurora Program (early 2000s)

The European Space Agency has the long-term vision of sending a human mission to Mars by 2030, the Aurora Program.

Russian Mission Proposals (current)

A number of Mars mission concepts and proposals have been put forth by Russian scientists. Stated dates were for a launch sometime between 2016 and 2020. The Mars probe would carry a crew of four to five cosmonauts, who would spend close to two years in space.

Another proposal for a joint mission with ESA is based on two spacecraft being sent to Mars, one carrying a six-person crew and the other the expedition's supplies. The mission would take about 440 days to complete with three astronauts visiting the surface of the planet for a period of two months. The entire project would cost $20 billion dollars and Russia would contribute 30 per cent of these funds.

A ground-based biomedical experiment called Mars-500 simulating manned flight to Mars is planned to start in 2007 in Russia.

Preparedness

A number of nations and organizations have long-term intentions to send humans to Mars. The state of their readiness is summarized below.

• The United States has a number of missions currently exploring Mars, with a sample-return planned in the near future. The Orion spacecraft, currently under development by NASA, could ferry astronauts from the surface of Earth to join a Mars-bound expedition in Earth orbit and then back to Earth's surface once the expedition has returned from Mars.

• The European Space Agency has sent robotic probes, and has long-term plans to send humans but has not yet built a human-capable launcher.

• Russia (and previously the Soviet Union) has sent a large number of failed probes. It can send humans into Earth-Orbit and has extensive experience with long-term manned orbital space flight due to its space station programs. Russia does not have a launcher capable of sending humans to Mars, although the Kliper program was proposed as the Russian-European counterpart to the United States' Orion Spacecraft.

• Japan's robotic missions to Mars have so far failed.

• China plans its first robotic mission to Phobos in 2009 in cooperation with Russia. China was the third country after Russia and the USA to launch humans into Earth orbit.

Criticism

Some scientists have argued that attempting manned flight to Mars would actually be counterproductive for science. For example, in 2004 the Special committee on the funding of Astrophysics, a committee of the American Physical Society, stated that "shifting NASA priorities toward risky, expensive missions to the moon and Mars will mean neglecting the most promising space science efforts". Moreover, given the rapidly advancing capabilities of robotic explorers, including the Mars Exploration Rovers' demonstrated ability to carry out continuous observations during multi-year sojourns on the hostile Martian surface, it is not obvious whether human explorers would actually return more science data for the dollar.

In the even longer term (centuries hence), some scientists believe Mars to be a good candidate for terraforming and human colonization, though other prominent skeptics dispute the practicality of both. Many scientists have argued that if life is found on Mars, all human activities on the planet should be carried out with the goal of preservation in mind. Others argue that the presence of life on Mars would imply that life is prevalent throughout the universe; decreasing the relative importance of Martian microbes.

See also

• Exploration of Mars
• Colonization of Mars
• MARS-500
• Mars in fiction
• Manned Venus Flyby
• Space weather
• Space radiation

External links

• Human Exploration of Mars: The Reference Mission Design Reference Mission 1.0
• Reference Mission Version 3.0, Addedum to Human Exploration of Mars Design Reference Mission 3.0
• Mars Expeditions List of all manned mission projects

References

• a longer bibliography can be found in the bibliography of Portree's book, available in pdf format from NASA.