Colonization of Mars

The colonization of Mars by humans is the focus of serious study because surface conditions, such as the availability of frozen ground water, make it the most hospitable planet in the solar system other than Earth. While the Moon due to its close proximity has been proposed as the first location for human colonization, lunar gravity is only 16% that of Earth's while Martian gravity is a more substantial 38%. There is more water present on Mars than the Moon, and Mars has a thin atmosphere. These factors give Mars a greater potential capacity to host organic life and human colonisation.

Both the Moon and Mars, as potential settlement sites, have the disadvantages of cost and risk associated with landing within gravity wells, which may make asteroids another option for early expansion of humans into the solar system.