English: This September 1967 photograph shows workmen removing a mockup of the Saturn V S-IVB stage that housed the Skylab Orbital Workshop (OWS) from the Marshall Space Flight Center (MSFC), building 4755. The mockup was shipped to McDonnell Douglas in Huntington, California for design modifications. NASA used the mockup as an engineering design tool to plan structures, equipment, and experiments for Skylab, an orbiting space laboratory. The MSFC had program management responsibility for the development of Skylab hardware and experiments, including the OWS. Launched on May 14, 1973, Skylab orbited Earth from 1973 to 1979. The 169,950-pound space station included a workshop, solar observatory, docking adapter and systems to allow three crews to spend up to 84 days in space.