With all the futuristic talk today about missions to Mars, lunar bases and asteroid mining, it's easy to forget that man has already been living off of the planet on and off for decades. Forty years ago today, Skylab -- America's first outpost in space -- was launched. The three-man orbiting laboratory was designed to conduct scientific experiments in space, such as studies of the effects of weightlessness on man and other living organisms, and observations of the sun.

Here's a look back at the pioneering Skylab mission, including mechanical failures, an aborted rescue mission, a crew mutiny and an unplanned crash landing on Earth.