The words “space station” mean many things to many people. In fact, a very wide range of craft have been studied under this name over the years. The range of such studies has included large rotating craft providing an artificial gravity environment and accommodating hundreds of people (the type envisaged by Arthur Clarke in his book, 2001: A Space Odyssey) and small two or three-man craft designed for mission durations of 30 days. The one thing that all these programmes have in common is that they emphasise the use of spacecraft for the conduct of meaningful and beneficial investigations using the vantage point or the environmental features of space. In addition, they have involved the presence of man as a means of providing more effective conduct of the assigned tasks. This approach differs somewhat from activities that are strongly aimed at specific and demanding mission accomplishments, missions which place great emphasis on reliable and safe operation of the flight hardware and the demonstration of new operational techniques. Nevertheless, past programmes such as Mercury, Gemini, and Apollo have included many of the basic space station ideas.