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.

Launch The 170,000-pound space station was launched from Kennedy Space Center on May 14, 1973 on a Saturn V rocket. The first three-man crew arrived 12 days later. Image: NASA

Early Concept Drawing This concept drawing was created in 1966 by George E. Mueller, NASA associate administrator for Manned Space Flight. It depicts the major elements of the project that became known as Skylab several years later, in 1970. Image: (NASA)

The Mission The mission sequence for the first two phases of the Skylab program are shown in this diagram. Skylab 1 was the deployment of the space station. Skylab 2 the first delivery of a crew to the station via a Command Service Module adapted form the Apollo program. Image: NASA

Skylab Illustrated This illustration shows a cutaway of Skylab with all its major components. The Command and Service Module was a hand me down from the Apollo program that was used to ferry the crew to the station. The Apollo Telescope Mount was a solar observatory that carried eight different solar experiments including x-ray telescopes, an x-ray and extreme ultraviolet camera, an ultraviolet spectroheliometer, a white-light coronagraph and hydrogen-alpha telescopes. The experiments made some discoveries about coronal holes and x-ray bright points. The Orbital Workshop, which housed the work areas, living quarters and most of the supplies. The workshop from the backup Skylab is on display at the National Air and Space museum. Image: NASA

Mission Patches Each of the three manned Skylab missions had its own patch emblazoned with the names of the crew. The numbering of the missions was the cause of some confusion at NASA. In the official numbering scheme, the first, unmanned mission was named Skylab 1, and the later manned missions were numbered two through four. But some documents used a different numbering scheme that started with the first manned mission (officially known as Skylab 2), and this latter scheme is what ended up on the patches. Image: (NASA)

Dental Exam Joseph Kerwin, medical officer of the Skylab 2 mission, gives a dental exam to commander Pete Conrad. Image: (NASA)

Skylab 3 Skylab 3, the second manned mission to the space station, encountered problems on the way to the space station. As the Command Service Module neared Skylab, fuel leaks developed in two of the four thrusters. The astronauts were able to dock safely, but concerns about a safe return prompted NASA to get an Apollo spacecraft ready to come to the rescue. Skylab was ready for such a rescue mission because it had the ability to have two spacecraft docked to it at the same time. NASA decided two thruster quads were enough for safe reentry and the rescue was canceled. Image: NASA

Spacewalk Astronaut Owen Garriott photographed during the Skylab 3 mission. Garriott had just deployed the Skylab Particle Collection S149 Experiment, the goal of which was to collect and study interplanetary dust particles. Image: (NASA)

Space Spiders The second manned mission to Skylab, known as Skylab 3, included experiments on pocket mice, vinegar gnats and spiders. Sadly, the mice and gnats were killed by a power failure. But a high school student's experiment on the effect of weightlessness on spider web formation was successful. Judy Miles of Lexington, Kentucky sent two cross spiders, named Arabella and Anita, to Skylab. The spiders were initially disoriented but eventually began making webs. Their first attempts were not their best work. But eventually they got used to dealing without gravity and built perfectly respectable webs much like those spun on Earth. Both spiders and some web samples were brought back to Miles to study. Other high school student experiments during Skylab 3 included studies of x-rays from Jupiter, cytoplasmic streaming, immunology, lbration clouds, mass measurement and neutron analysis. In total, 19 student-led experiments were conducted during the Skylab mission. Image: Arabella on a web built in zero gravity on the Skylab space station. (NASA)

Dinner Astronaut Owen Garriott enjoys a meal during the Skylab-3 mission. Food on Skylab was better than that on earlier spaceflights. Instead of squeezing liquified food from plastic tubes, crew members could choose their own meals and prepare them to taste. The tray contained heating elements to keep everything warm. Image: (NASA)

Skylab 4 The final Skylab mission was manned by three rookie astronauts. The 84-day mission would be the longest yet. However, things did not go smoothly. The crew began complaining that too much work was being demanded of them and that they couldn't keep up with the planned tasks. They began falling behind schedule, and NASA began pushing them harder to catch up. About halfway through the mission, the astronauts held what could be described as a mutiny: They announced they'd be taking a day off and turned off their communications with Earth. They apparently spent the day relaxing and admiring the view. Afterward, NASA agreed to lighten the load, and the astronauts began performing better. You may not recognize their names -- Gerry Carr, Bill Pogue and Ed Gibson -- because their stunt resulted in none of them ever flying again. Images: Above: Edward Gibson and Gerry Carr in the airlock module (NASA). Below: Skylab 4 crew. From L-R: Gerry Carr, Ed Gibson and Bill Pogue (NASA).

Undocking Skylab seen from the Apollo Command Module undocks with the crew of Skylab 4 and moves away for the last time in February 1974. In the late 1970s, NASA considered sending another mission to Skylab using the new Space Shuttle, which they expected to be ready for launch by the end of the decade. These missions would have boosted Skylab into a higher orbit, then renovated it and even expanded it. Astronauts would need to repair or replace a gyroscope and other navigational equipment, but otherwise the station was deemed to be safe and operational. But it wasn't to be. The first orbital flight of the Space Shuttle took place in 1981, nearly 2 years after Skylab fell to Earth in a controlled re-entry. Image: (NASA)