Prevention and treatment of space sickness in shuttle-orbiter missions

Today it is impossible accurately to predict susceptibility to space sickness of crew members making their first transition into orbit, for want of a ground-based validated model of free fall. Even assuming that space sickness is simply a specific designation for motion sickness that may be experienced in orbital flight (and here agreement is not general), preventive therapy poses difficult problems because, for a priori reasons, either all crew members or none should receive treatment. If all receive preventive therapy, everyone should execute head movements in a programmed manner to ensure rapid adaptation to the environment; at least a large minority will not benefit but rather will experience whatever sideeffects inevitably accompany administration of a drug. If none receive preventive therapy prelaunch, at least a large minority will pose two problems--treatment for acute motion sickness and rapid acquisition of adaptation. Trade-offs will involve the identification of long-acting antimotion sickness drugs for use prelaunch that will be efficacious for at least 90% of those going aloft for the first time and the effectiveness of combining rapid adaptation with treatment of motion sickness. The following report describes recent experiments dealing with these problems.