The intangibles of habitability during long duration space missions

In this paper the nature and meaning of habitability a r e discussed in relation to the requirements for long duration manned space missions. Several models of habitability are examined, and it is suggested that habitability can be considered a s that equilibrium state, result ing f r o m man-machineenvironment-mission interactions which permi ts man to maintain physiological homeostasis, adequate performance, and psychosocial integrity. The attr ibutes of habitability a r e examined, and, indices of habitability a r e discussed. quirements for optimum habitability, an exerc ise which would involve consideration of every aspec t of the interactions occurr ing in the en t i re man-machine-environment-mis sion complex. Attention is focussed instead on some of the l e s s common aspects, and a discussion ensues on requirements for f r ee internal volume, configuration, privacy ( terr i tor ia l i ty) , personal hygiene, illumination, decor, color, recreation, and the u s e of le i sure t ime, during a long duration manned space mission. N o attempt is made to examine a l l the r e -