Behavioral health: the propaedeutic requirement.

Concern about the behavioral effects of spaceflight can be traced back a half century to the earliest preparatory bioastronautics experiments in the mid-1 950s. A central focus of the first primate suborbital flights, as well as the orbital chimpanzee pretest flights of Project Mercury, was the effects of such stressful ventures on the learned performances of these space behavioral health pioneers. The hiatus in spaceflight behavioral health experimental investments that followed these early initiatives began with the advent of the 'human astronaut' era of the mid-1960s, and has dominated the last several decades. Contemporary concerns in this regard have most recently been articulated by a turn-of-the-century Committee of the Institute of Medicine, National Academy of Sciences, providing a visionary view of space medicine during travel beyond Earth orbit. This 2-yr study focused on those most complex behavioral health interactions involving humans in extreme, isolated, and confined microsocieties-areas that have not received the necessary level of attention. The evident behavioral health issues raised by the prospect of long-duration exploratory missions beyond Earth orbit, including performance and general living conditions, recovery and support systems, and the screening, selection, and training of candidate participants are reviewed and discussed.