The achievement of future manned space flight no longer appears to be subject to serious question. Solution of a broad variety of problems involved in the attainment of manned space flight requires extensive scientific activity and progress--but the time is approaching when the scale of accomplishments will be in balance with the scale of requirements. Because the achievement of space flight also requires that man survive and function productively, one of the most important areas of space research resides in the life sciences, more frequently referred to by the term "space medicine."