Mars should be colonized, not the moon.

Ill first state the benefits to colonizing the moon as many of them will already address the perceived benefits of Mars over the moon. Proximity 1 way distance to the moon, 238,900 miles. 1 way distance to Mars, 140,000,000 miles. In the time it take you just to travel to Mars once, you could have made several trips shuttling cargo and equipment from earth where factories are already present and much more easily tooled for making things needed in space. This close distance also means the trip can be done on much less fuel and a much smaller vessel. This also means the vessel would be much cheaper and readily made on earth than one that is built for a journey 586 times farther away. At the fastest speed on record of any of our ships moving away from the sun was 100,000 mph [NewHorizons Mission to Pluto], and that was only carrying a space probe and cost us 675M. Even using constant velocity as the method of travel, at that speed, it would take nearly 2 months to get to Mars on a one way trip. Now imagine a ship that has to carry lifesupport and terraforming machinery with it to that speed. There would be sacrifices to speed because of the sheer amount of fuel it would take to get something like that into space ... let alone get it up to a speed like that. Tidal Locked The moons proximity and the fact that its tidally locked with earth make for several additional benefits. One, Space transportation ideas have arisen that involve using the moons stationary position to create a channel for more easily transporting material to and from it without the use of rockets, see space elevator. Second, communication of a colony is a breeze since it will always be facing the earth and always have direct contact with some point on earth or its satellites we already have in orbit. Return trips will be easier as there wont be any waiting required for 'optimal' conditions for a launch. The moons orbit is nearly circular and the site of your launch area will always be facing earth at any given time. Gravity Mars' gravity is 37% that of Earth. The moon's gravity is 17% of Earth's. Exercise would still be a necessity and the difference between the two would barely be noticeable by anyone having lived on earth their whole life. This has proven to be a rather easy problem to overcome by astronauts in zero gravity, so I don't see an additional 20% being all that big a factor in the muscle loss issue. As far as holding an atmosphere ... both are incapable of it on their own, and there is no capability we have that could change the physics of the planet to have it maintain one for us composed of the gases we need to survive. I do see a benefit though, to there being less gravity, as far as work goes. Mining and building would be easier on the moon. It could support much larger structures by maximizing a materials load bearing capabilities. Radiation Radiation could be a problem to any open terraformed colonies. Domes solve this issue. The additional radiation the moon receives is the a benefit as plant life in greenhouses will more readily have access to light. Resources and Habitability As a resource the moon itself is not optimal, no. The majority of its rare earth elements would have to come from earth, which would be much easier done than Mars. Solar panels are becoming a pretty lightweight thing to move into space, if built on earth. The orientation of the moon and its non existent atmosphere make it an optimal location for massive solar fields. Atmospheres are actually a liability if relying solely on solar energy. Another point where terraforming a planet makes for inefficiency. Water If the water on Mars were melted and also made gaseous for an atmosphere, it would continuously lose the water in the air. The only thing keeping that water on there now is the fact that its frozen. Its melting point and boiling points are pretty close and the atmospheric pressure allows for the triple point of water to exist in ranges found here on earth (a fact we take it for granted). A bit of all 3 states will exist and the gas form will rapidly be lost. Not maintaining critical points in domes would be a constant chore without relocating the planets location in relation to the sun ... earthlike atmospheres will not work on either the moon or Mars. The biggest benefit is cost. The cost of launching and operating on Mars far surpasses the cost of operation on the moon using the earth as a site for resources. Mars might eventually begin to pay for itself and become self sufficient ... but it would take much longer and a much more substantial initial investment. http://blogs.scientificamerican.com... http://www.universetoday.com... http://en.wikipedia.org...(thermodynamics) http://solarsystem.nasa.gov...