I.

Introduction

Skylab, first American space station. In 1973 the National Aeronautics and Space Administration (NASA) launched the 100-ton Skylab module into orbit around the earth from the Kennedy Space Center in Cape Canaveral, Florida. Each of the three crews of Skylab astronauts was launched separately in an Apollo command and service module (CSM), and they stayed in Skylab for periods of 28, 59, and 84 days, respectively. The Skylab astronauts proved that it was feasible for humans to live and work in a weightless environment for extended stays without suffering ill effects. Astronauts also made key repairs to Skylab in space, paving the way for future repairs of satellites from the space shuttle. In addition, the Skylab astronauts successfully completed experiments on solar physics, earth observations, and crystal growth in zero gravity.