Space gerontology.

The initiation of the shuttle program, with the possibility of flying older persons and persons other than trained astronauts, makes it necessary to examine the effects of the weightless environment throughout the life cycle. The model of a hypothalamic clock as the timing mechanism for lifespan suggests that weightlessness and hypergravity may prove useful tools in the investigation of aging processes. For these reasons geriatrics and gerontology enter into the field of aerospace biology, both practically in crew selection and in the development of clinically useful data on the nature of human age changes and their control.