Future thrusts in life sciences experimentation in space

Biomedical research objectives for future Shuttle and/or Space Station missions are discussed, with a focus on experiments exploring the physiological effects of microgravity. Experience up to the present is found to indicate that molecular-level processes are not much affected by the space environment, so that future experiments should concentrate on larger-scale phenomena. Areas considered include cardiovascular, respiratory, skeletal, and muscular physiology; metabolism; neurophysiology; and behavior. Radiation effects are seen as well as understood on the basis of ground-based data, with the possible exception of HZE-particle radiation. The need for carefully constructed ground research to prepare for space experiments is stressed.