The International Space Station (ISS) has been in operation with research ongoing since November 2, 2000. But it was the first US space station – Skylab -- that helped pave the way for permanent operations in Low-Earth Orbit (LOE). The three man crew of Charles Conrad, Joseph Kerwin, and Paul Weitz launched aboard a Saturn IB rocket fifty years ago this week, on May 25, 1973. This followed the launch of the unmanned Skylab Space Station a week earlier by a Saturn V on May 14, 1973 – The last launch of the venerable Saturn V booster. Skylab orbited the Earth from 1973 to 1979. The 169,950-pound space station included a workshop, a solar observatory, a multiple docking adapter, and systems to allow three crews to spend up to 84 days in space. Altogether, there were three Skylab expeditions of 28, 59, and 84 days that produced a vast study of the Earth -- its crops, weather, changes in environment, as well as a revealing study of the Sun. Skylab moved the space program from the realm of the spectacular, into a new phase that could be characterized as almost businesslike and contributed to an orderly transition from the Apollo era to the Space Shuttle.