Ever since the Apollo program put the moon within our reach, establishing a lunar outpost has seemed a logical next step. Earth's natural satellite offers several advantages over more distant destinations, such as Mars or Saturn's moon Titan. First, it's relatively close, which means crews could get back and forth from the Earth and moon in just a few days. Additionally, a lunar base would enable use to learn a lot about the effects of low gravity, isolation, high doses of cosmic radiation, and disrupted circadian rhythms on human space colonists — knowledge that would be invaluable when we eventually venture to other worlds [source: Fecht].
Additionally, the moon's low gravity and closeness to Earth would make it an ideal location for a spaceport from which astronauts could embark on missions to Mars and worlds even further away. And in terms of long-term possibilities, the moon is a big place — its surface is roughly the size of Africa — and it has plenty of room for human colonists [source: Gent].
But living on the moon won't be any picnic. With no atmosphere, it experiences huge temperature extremes, swinging from minus 298 degrees Fahrenheit (minus 183 degrees Celsius), at night, to 224 degrees Fahrenheit (106 degrees Celsius) in the daytime at the equator [source: CalTech]. Its surface is also peppered constantly by micrometeorites and cosmic rays [source: Redd].
To survive those hostile environmental conditions, some experts think that colonists will likely have to place their habitats under the lunar soil or at the base of a lava tube [source: Redd]. Others envision domes built by robots equipped with 3D printers, which would provide protection [source: Gent].
Then there's the issue of food and water. In 2018, a team of scientists spotted the first definitive evidence of water ice on the lunar surface, a discovery that suggests that future lunar colonists might be able to extract their own supply, which could provide water for drinking and for irrigating plants in lunar greenhouses, as well as a raw material for rocket fuel [sources: NASA, Grush].
NASA's current plan for returning to the moon involves building a lunar orbital station, the Gateway, which will serve as a staging area for teams of astronauts to make short visits to the lunar surface. The first part of the Gateway is scheduled to be sent into space on a private rocket in 2022 [source: NASA].
Keep reading to find out what the plan is for Mars.