A plan to establish ongoing explorations, and then permanent bases, on
Mars using present-day technology. Devised by
Robert Zubrin and David Baker in 1990 and still not implemented, although some of the design principles have been used for several of
NASA's latest ventures, including the
Pathfinder mission.
In Zubrin's own Arctic metaphor, Mars Direct is a "dog sled" approach to interplanetary exploration, as opposed to the conventional "Royal Navy" approach NASA and other space agencies typically use. The basic principles are simplicity, small ships, and "living off the land" by using Martian atmosphere to produce fuel for the return trip to Earth. Parts of the landers themselves would be used to build a temporary base, which would later be added onto to make a more permanent one. According to Zubrin's estimates, Mars Direct would cost between 20 and 30 billion dollars over a ten-year period, as opposed to the prohibitive $450 billion estimate given for a "Battlestar Galactica" style, massively redundant and 100% safe Mars mission in NASA's infamous 90-Day Report. Zubrin believes that many of the safety precautions, redundancies and auxiliary orbital installations of NASA's proposal are unnecessary. Opinions on this are understandably divided.
Stages of the Mars Direct exploration plan:
- 2005 (We're off schedule by now, because Zubrin originally proposed starting in the late Nineties) - An unmanned multistage rocket with four Space Shuttle main engines and two solid rocket boosters is launched, carrying an (unmanned) Earth Return Vehicle. The ERV carries a small nuclear reactor, a chemical processing unit which will be used to combine Martian carbon dioxide with hydrogen brought from Earth, producing methane for fuel, and water. The water will be split into oxygen for propellant, and hydrogen, which is recycled into the process to make more methane and water. The ERV will arrive at Mars with only 6 tonnes left of liquid hydrogen, but after six months of work on Mars it should produce around 108 tonnes of methane and oxygen - enough for the return flight to Earth and some extra for use in ground vehicles on Mars.
- 2006 - When the ERV is fully fueled and extra fuel for ground operations has been produced, Sojourner-type robots will be used to explore the vicinity of the landing zone, in order to locate an ideal landing site for the following mission, which will be manned.
- 2007 - Two more ships will be launched almost simultaneously by the same kind of boosters that launched the first ERV - another unmanned vehicle with another ERV, and a "habitation module", containing four astronauts cross-trained in multiple disciplines. The upper stage of the booster is attached to the "hab" by a tether, which will be deployed en route to Mars, causing the hab and the booster stage to rotate in order to simulate gravity during the voyage. On reaching Mars, the booster stage will be jettisoned and the hab will land near the original ERV. If the hab cannot land close enough to the ERV, the second ERV (which has been following the hab at a slower pace) will be brought to a landing near it.
- 2008 - If the hab's landing was properly completed near the original ERV, the second ERV will be landed about 800 kilometers away and begin fuelling itself, to be used by the second manned mission in 2010. Meanwhile, the human crew of "Hab 1" will begin a 500 day stay on Mars. Their top priority will be looking for H20 ice, but they will also be doing geological surveys and looking for signs of life. Explorations will be conducted via robots and pressurized rovers. They will leave Mars in ERV 1 in 2009, leaving their hab unit behind, with rovers, greenhouse, power plant, and instrumentation. This complex is now Mars Base 1.
- 2010 - Another manned ship with a hab unit is launched, as well as another ERV. The hab will land at Base 2 - where ERV 2 landed; and ERV 3 will be sent to a new location where Base 3 will be begun by the next crew.
Using this basic schedule, a number of bases could be set up on Mars within a decade, each one opening up new areas to explore. None of these bases would be truly permanent structures, but their components can be re-used by future crews, and will eventually be recycled into the permanent settlement, when we decide on the right site to build it. Each mission would have an ERV already prepared for it before it launched, minimizing the size of the ship required for the mission. Naturally there will be risks, but it is technologically feasible, and personally, I can't understand why we aren't doing it now. If NASA is waiting for volunteers, I'm there.
Outline based on "The Case for Mars", Robert Zubrin, 1996. Highly recommended, very accessible.