14 CFR 1214.302 - Background.
(a) The Space Transportation System (STS) has been developed to expand the Nation's capabilities to utilize the unique environment of space. It provides opportunity for individuals other than career astronauts to participate as onboard members of the flight crew under specified conditions. The purpose of such participation by these individuals is to ensure the achievement of the payload or mission-related objectives.
(b) The STS will provide these additional crew members with a habitable working environment and support services in such a way as to require a minimum of dedicated space flight training, allowing them to concentrate their efforts on the accomplishment of their scientific, technical, or mission objectives.