Mars Direct

Mars Direct

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Mars Direct is a proposal for a manned mission to Mars
Manned mission to Mars
A manned mission to Mars has been the subject of science fiction, engineering, and scientific proposals throughout the 20th century and into the 21st century...

. Proponents of the scheme have claimed it to be both cost-effective and that it can be conducted with current technology. It was originally detailed in a research paper by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 engineers Robert Zubrin
Robert Zubrin
Robert Zubrin is an American aerospace engineer and author, best known for his advocacy of the manned exploration of Mars. He was the driving force behind Mars Direct—a proposal intended to produce significant reductions in the cost and complexity of such a mission...

 and David Baker in 1990, and later expanded upon in Zubrin's 1996 book The Case for Mars
The Case For Mars
The Case for Mars: The Plan to Settle the Red Planet and Why We Must is a nonfiction science book by Robert Zubrin, first published in 1996....

. It now serves as a staple of Zubrin's speaking engagements and general advocacy as head of the Mars Society
Mars Society
The Mars Society is an international space advocacy non-profit organization dedicated to promoting the human exploration and settlement of the planet Mars. It was founded by Robert Zubrin and others in 1998 and attracted the support of notable science fiction writers and filmmakers, including Kim...

, an organization devoted to the colonization of Mars
Colonization of Mars
The colonization of Mars by humans is the focus of speculation and serious study because the surface conditions and availability of water on Mars make it arguably the most hospitable planet in the solar system other than Earth...

.

Scheme


The plan involves several launches. Proponents of Mars Direct have suggested that the heavy-lift boosters required would be no larger than the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...

 used for the Apollo missions, and could potentially be derived from Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

 components.

The first flight would bring an unmanned Earth Return Vehicle to the red planet, with a supply of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

, a chemical plant and a small nuclear reactor
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...

. Once there, a series of chemical reactions (the Sabatier reaction
Sabatier reaction
The Sabatier reaction or Sabatier process involves the reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst to produce methane and water. Optionally ruthenium on alumina makes a more efficient catalyst...

 coupled with electrolysis) would be used to combine a small amount of hydrogen (8 tons) carried by the Earth Return Vehicle with the carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 of the Martian atmosphere to create up to 112 tonnes of methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

 and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. 96 tonnes of these would be needed to return the Earth Return Vehicle to Earth at the end of the mission, the rest would be available for Mars rovers. Proponents of the scheme have suggested that this process would take approximately ten months to complete.

Some 26 months after the Earth Return Vehicle is originally launched from Earth, a second vehicle, the "Mars Habitat Unit", would be launched to coincide with a low-energy transfer window to Mars, and would carry a crew of four astronauts. This would not be launched until the automated factory had signaled the successful production of the chemicals. This vehicle would take some six months to reach Mars. During the trip, supporters of Mars Direct have suggested that artificial gravity
Artificial gravity
Artificial gravity is the varying of apparent gravity via artificial means, particularly in space, but also on the Earth...

 could be generated by tying the spent upper stage of the booster to the Habitat Unit, and setting them both rotating about a common axis.

On reaching Mars, the upper stage would be jettisoned, with the Habitat Unit aerobraking
Aerobraking
Aerobraking is a spaceflight maneuver that reduces the high point of an elliptical orbit by flying the vehicle through the atmosphere at the low point of the orbit . The resulting drag slows the spacecraft...

 into Mars orbit before soft-landing in proximity to the Earth Return Vehicle. Precise landing would be supported by a radar beacon started by the first lander. Once on Mars, the crew would spend 18 months on the surface, carrying out a range of scientific research, aided by a small rover vehicle carried aboard their Mars Habitat Unit, and powered by the methane produced by the Earth Return Vehicle. To return, they would use the Earth Return Vehicle, leaving the Mars Habitat Unit for the possible use of subsequent explorers. The propulsion stage of the Earth Return Vehicle would be used as a counterweight
Counterweight
A counterweight is an equivalent counterbalancing weight that balances a load.-Uses:A counterweight is often used in traction lifts , cranes and funfair rides...

 to generate artificial gravity for the trip back.

Components


The Mars Direct proposal includes a component for an Earth Return Vehicle (ERV) and a Mars Habitat Unit (MHU).

Earth Return Vehicle


The Earth Return Vehicle is a two-stage vehicle. The upper stage comprises the living accommodation for the crew during their six-month return trip to Earth from Mars. The lower stage contains the vehicle's rocket engines and a small chemical production plant.
































































































Round trip payload
Crew compartment 7,100 kg
Reaction control system 400 kg
Biconic brake 2,450 kg
Stage 1 (dry) 6,330 kg
Stage 2 (dry) 1,770 kg
Mars-bound payload
Hydrogen for propellant production 5,810 kg
SP-100
SP-100
SP-100 was a U.S. research program for nuclear fission reactors in space. It was started in 1983 by NASA, the US Department of Energy and other agencies. It developed a reactor with heat pipes transporting the heat to thermionic converters...

 Reactor
4,500 kg
Earth-bound payload
Crew 450 kg
Suits 300 kg
Consumables (dry food) 2,000 kg
Soil Samples 150 kg
Stage 1 propulsion system
Usable propellant (methane / oxygen) 70,160 kg
Dry mass 8,850 kg
Total engine thrust 85,237 kgf
Kilogram-force
A kilogram-force , or kilopond , is a gravitational metric unit of force. It is equal to the magnitude of the force exerted by one kilogram of mass in a gravitational field...

 (835.89 kN)
Specific impulse 373 s (3.65 kN·s/kg)
Stage 2 propulsion system
Usable propellant (methane / oxygen) 25,000 kg
Dry mass 2,560 kg
Total engine thrust 9,059 kgf (88.84 kN)
Specific impulse 373 s (3.65 kN·s/kg)

Mars Habitat Unit


The Mars Habitat Unit is a 2- or 3-deck vehicle providing a comprehensive living and working environment for a Mars crew. In addition to individual sleeping quarters which provide a degree of privacy for each of the crew and a place for personal effects, the Mars Habitat Unit includes a communal living area, a small galley, exercise area, and hygiene facilities with closed-circle water purification. The lower deck of the Mars Habitat Unit provides the primary working space for the crew: small laboratory areas for carrying out geology and life science research; storage space for samples, airlocks for reaching the surface of Mars, and a suiting-up area where crew members prepare for surface operations. Proponents of the design have argued that protection from harmful radiation while in space and on the surface of Mars (e.g. from solar flares) is provided by a dedicated "storm shelter" in the core of the vehicle.

The Mars Habitat Unit would also include a small pressurized rover that is stored in the lower deck area and assembled on the surface of Mars. Powered by a methane engine, it is designed to extend the range over which astronauts can explore the surface of Mars out to 320 km.

Since it was first proposed as a part of Mars Direct, the Mars Habitat Unit has been adopted by NASA as a part of their Mars Design Reference Mission, which utilizes two Mars Habitat Units - one of which flies to Mars unmanned, providing a dedicated laboratory facility on Mars, together with the capacity to carry a larger rover vehicle. The second Mars Habitat Unit flies to Mars with the crew, its interior given over completely to living and storage space.

To prove the viability of the Mars Habitat Unit, the Mars Society
Mars Society
The Mars Society is an international space advocacy non-profit organization dedicated to promoting the human exploration and settlement of the planet Mars. It was founded by Robert Zubrin and others in 1998 and attracted the support of notable science fiction writers and filmmakers, including Kim...

 has implemented the Mars Analogue Research Station Program
Mars Analogue Research Station Program
The Mars Analog Research Station Program is an international effort spearheaded by The Mars Society to establish a network of prototype research centers where scientists and engineers can live and work as if they were on Mars, to develop the protocols and procedures that will be required for human...

 (MARS), which has established a number of prototype Mars Habitat Units around the world.






















































































Round Trip Payload Tonnes
Main Structure 8.52
Decks 6.00
Airlock / Radiation Shelter 1.82
Airlock Doors 0.40
Interior Fittings  
Walls 0.30
Furniture 0.50
Science Equipment 1.00
Exercise and Health 0.20
Plumbing and Lighting 1.00
Replacement Air (3 charges) 0.81
Solar Panels 0.25
Life Support System 4.00
Consumables for Crew 11.76
Crew of 6 0.45
Personal Effects 0.70
Spacesuits 0.30
Pressurised Rover 2.00
Deployed Surface Science 0.40
Contingency 5.00

Revisions


Since Mars Direct was initially conceived, it has undergone regular review and development by Zubrin himself, the Mars Society
Mars Society
The Mars Society is an international space advocacy non-profit organization dedicated to promoting the human exploration and settlement of the planet Mars. It was founded by Robert Zubrin and others in 1998 and attracted the support of notable science fiction writers and filmmakers, including Kim...

, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...

 and others.

Zubrin and Weaver developed a modified version of Mars Direct, called Mars Semi-Direct, in response to some specific criticisms. This mission consists of three spacecraft and includes a "Mars Ascent Vehicle" (MAV). The ERV remains in Mars orbit for the return journey, while the unmanned MAV lands and manufactures propellants for the ascent back up to Mars orbit. The Mars Semi-Direct architecture has been used as the basis of a number of studies, including the NASA Design Reference Missions.

The NASA model, referred to as the Design Reference Mission, currently on version 5.0, calls for a significant upgrade in hardware (at least 3 launches per mission, rather than two), and sends the ERV to Mars fully fuelled, parking it in orbit above the planet for subsequent rendezvous with the MAV.

The Mars Society and Stanford studies retain the original 2-vehicle mission profile of Mars Direct, but increase the crew size to six.

Mars Society Australia
Mars Society Australia
is an Australian space advocacy organisation, which was formed in 1998. Its goals are to:*Undertake broad public outreach to instill the vision of pioneering Mars.*Support government funded Mars exploration programs around the world....

 developed their own four-person Mars Oz reference mission, based on Mars Semi-Direct. This study uses horizontally landing, bent biconic shaped modules, and relies on solar power and chemical propulsion throughout, where Mars Direct and the DRMs used nuclear reactors for surface power and, in the case of the DRMs for propulsion as well. The Mars Oz reference mission also differs in assuming, based on space station experience, that spin gravity will not be required.

The Mars Society has argued the viability of the Mars Habitat Unit concept through their Mars Analogue Research Station program. These are two or three decked vertical cylinders ~8 m in diameter and 8 m high. Mars Society Australia plans to build its own station based on the Mars Oz design. The Mars Oz design features a horizontal cylinder 4.7 m in diameter and 18 m long, with a tapered nose. A second similar module will function as a garage and power and logistics module.

Mars Direct was featured on a Discovery Channel
Discovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...

 programs Mars: The Next Frontier in which issues were discussed surrounding NASA funding of the project, and on Mars Underground, where the plan is discussed more in-depth.

Alternatives


A modified proposal, "Mars for Less
Mars for Less
Mars for Less is a proposal for a near-term human Mars expedition that involves the use of existing Evolved Expendable Launch Vehicles...

", was developed by Grant Bonin, and has been adopted as the design reference mission for a new umbrella group of advocates, the MarsDrive consortium. The design retains most of the essential features of Mars Direct, but uses multiple medium-lift rocket launchers that are commercially available today (such as the Ariane V or the Delta rocket
Delta rocket
Delta is a versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. There have been more than 300 Delta rockets launched, with a 95 percent success rate. Two Delta launch systems – Delta II and Delta IV – are in active use...

) to launch the crew vehicles, and their propulsion, separately, and mate them in orbit. By doing so, the multi-billion dollar development cost of a new launch vehicle is avoided.

A modified proposal, called "Mars to Stay
Mars to Stay
Mars to Stay missions propose astronauts sent to Mars for the first time should stay there indefinitely, both to reduce cost and to ensure permanent settlement of Mars. Among many notable Mars to Stay advocates, former Apollo astronaut Buzz Aldrin has been particularly outspoken, suggesting in...

", involves not returning the first immigrant/explorers immediately, or ever. Dean Unick has suggested the cost of sending a four or six person team is one fifth to one tenth the cost of returning that same four or six person team. A quite complete lab can be sent and landed for less than the cost of sending back even 50 kilos of rocks. Twenty or more persons can be sent for the cost of returning four.

In fiction

  • Mars Direct is the mission mode used in Gregory Benford
    Gregory Benford
    Gregory Benford is an American science fiction author and astrophysicist who is on the faculty of the Department of Physics and Astronomy at the University of California, Irvine...

    's novel, The Martian Race, and in Geoffrey A. Landis
    Geoffrey A. Landis
    Geoffrey A. Landis is an American scientist, working for the National Aeronautics and Space Administration on planetary exploration, interstellar propulsion, solar power and photovoltaics...

    's novel Mars Crossing
    Mars Crossing
    Mars Crossing is a science fiction novel by Geoffrey A. Landis about an expedition to Mars, published by Tor Books in 2000. The novel was a nominee for the Nebula award, and won the Locus Award for best first novel in 2001....

    , as well as Zubrin's own novel, First Landing
    First Landing
    First Landing is a 2002 science fiction novel by Robert Zubrin that tells the story of the first manned space expedition to Mars. Zubrin is the head of the Mars Society, an organization lobbying the real world NASA to send astronauts to Mars...

    .

  • Mars Direct forms the basis for the 2000 film Mission to Mars
    Mission to Mars
    Mission to Mars is a 2000 science fiction film directed by Brian De Palma from an original screenplay written by Jim Thomas, John Thomas, and Graham Yost. The film's story details a fictional portrayal of a manned Mars exploration mission gone awry in the year 2020...

    .

  • In the Futurama
    Futurama
    Futurama is an American animated science fiction sitcom created by Matt Groening and developed by Groening and David X. Cohen for the Fox Broadcasting Company. The series follows the adventures of a late 20th-century New York City pizza delivery boy, Philip J...

    episode "The Luck of the Fryrish
    The Luck of the Fryrish
    "The Luck of the Fryrish" is the fourth episode in season three of Futurama. It originally aired in North America on March 11, 2001.-Plot:...

    ", a short clip shows the first man on Mars
    Mars
    Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

     with a spacecraft that resembles the Mars Habitat Unit.

  • In the West Wing
    The West Wing (TV series)
    The West Wing is an American television serial drama created by Aaron Sorkin that was originally broadcast on NBC from September 22, 1999 to May 14, 2006...

    episode "The Warfare of Genghis Khan
    The Warfare of Genghis Khan
    "The Warfare of Genghis Khan" is the 101st The West Wing episode and 13th of the fifth season. It originally aired on NBC February 1, 2004. Events circle around the detection of a nuclear detonation over the Indian Ocean. Written by Peter Noah and directed by Bill D'Elia, the episode contains guest...

    ", a NASA staffer describes Mars Direct to the skeptical White House
    White House
    The White House is the official residence and principal workplace of the president of the United States. Located at 1600 Pennsylvania Avenue NW in Washington, D.C., the house was designed by Irish-born James Hoban, and built between 1792 and 1800 of white-painted Aquia sandstone in the Neoclassical...

     Deputy Chief of Staff Josh Lyman
    Josh Lyman
    Joshua "Josh" Lyman is a fictional character played by Bradley Whitford on the television drama The West Wing. For the majority of the series, he was White House Deputy Chief of Staff in the Josiah Bartlet administration...

     and is able to convince him of its merit.

  • Both Mars Direct and Mars for Less concepts figure prominently in Brian Enke's 2004 novel, Shadows of Medusa.

  • A Mars Direct scheme is used in Larry Niven
    Larry Niven
    Laurence van Cott Niven / ˈlæri ˈnɪvən/ is an American science fiction author. His best-known work is Ringworld , which received Hugo, Locus, Ditmar, and Nebula awards. His work is primarily hard science fiction, using big science concepts and theoretical physics...

    's novel Rainbow Mars
    Rainbow Mars
    Rainbow Mars is a science fiction short story collection by Larry Niven. It includes the five previously published Svetz stories and the novel, also called Rainbow Mars in which humans from Earth visit Mars and find it populated by the creations of Edgar Rice Burroughs, Ray Bradbury, C. S. Lewis,...

    .

  • A Mars Direct scheme is used in Robert M. Blevins' 2005 novel The 13th Day of Christmas.

See also


  • Exploration of Mars
    Exploration of Mars
    The exploration of Mars has been an important part of the space exploration programs of the Soviet Union, the United States, Europe, and Japan. Dozens of robotic spacecraft, including orbiters, landers, and rovers, have been launched toward Mars since the 1960s...

  • List of manned Mars mission plans in the 20th century
  • Manned mission to Mars
    Manned mission to Mars
    A manned mission to Mars has been the subject of science fiction, engineering, and scientific proposals throughout the 20th century and into the 21st century...

  • The Case for Mars
    The Case For Mars
    The Case for Mars: The Plan to Settle the Red Planet and Why We Must is a nonfiction science book by Robert Zubrin, first published in 1996....

  • In-Situ Resource Utilization
    In-Situ Resource Utilization
    In space exploration, in-situ resource utilization describes the proposed use of resources found or manufactured on other astronomical objects to further the goals of a space mission....

  • Mars to Stay
    Mars to Stay
    Mars to Stay missions propose astronauts sent to Mars for the first time should stay there indefinitely, both to reduce cost and to ensure permanent settlement of Mars. Among many notable Mars to Stay advocates, former Apollo astronaut Buzz Aldrin has been particularly outspoken, suggesting in...

  • Mars Semi-Direct

External links