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 exotic moons, such as Saturn's Titan. First, it's relatively close, which means crews could get back and forth in just a few days. It also means communications between colonists and mission commanders on Earth wouldn't experience any significant delays. The moon would also make an ideal spaceport because rockets could escape its low gravity without expending so much energy. Finally, a lunar-based observatory would make it easier to study the universe and learn more about where our future travels should take us.
But living on the moon won't be any picnic. With no atmosphere, it experiences huge temperature extremes, swinging from 273 degrees Fahrenheit (134 degrees Celsius) at noon to minus 274 degrees Fahrenheit (minus 170 degrees Celsius) at night. Its surface is also peppered constantly by micrometeorites and cosmic rays. To survive this blitzkrieg, colonists will likely have to place their habitats under the lunar soil or at the base of a lava tube.
Then there's the issue of food and water. Scientists believe water is buried in the soil at the moon's south pole, but facilities will need to be built to extract it. And growing plants in the long lunar nights, with no insects for pollination, could prove to be difficult.
Despite these challenges, several countries are trying to put humans back on the moon. NASA's program, known as Constellation, seeks to put humans on the moon using a new generation of spacecraft -- the Ares launch rockets, the Orion crew vehicle and the Altair lunar lander. The target launch date had been set at 2020 until President Obama halted the program in early 2010. Meanwhile, some members of U.S. Congress have argued against dismantling Constellation, which would, in theory, revitalize the dream of building a successful lunar outpost.
Keep reading to find out what the plan is for Mars.