Space motion sickness during 24 flights of the space shuttle.

The incidence and severity of Space Motion Sickness (SMS) were determined from 24 flights of the Space Shuttle. A standardized questionnaire developed at the NASA-Johnson Space Center (JSC) was administered to all crewmembers postflight during an oral debriefing with the examining flight surgeon. Cases of SMS were graded mild, moderate or severe using criteria developed at the JSC. The incidence of SMS during a first Shuttle flight for 85 crewmembers was 67% (57 cases). There were 26 mild cases (30%), 20 moderate (24%), and 11 severe (13%). Differences were found between males and females, crew positions (Commander, Pilot, Mission Specialist, etc.), and age groups, which were not statistically significant (p greater than 0.05), but would suggest future research into the mechanism, prevention, and treatment of SMS. The 26 crewmembers with a second flight showed a reduction in SMS incidence to 46%, but the change was not significant compared with the first flight. Nine crewmembers (35%) showed a reduction in SMS severity comparing first and second flights, yet there was no significant difference in the mean time between flights for crewmembers with SMS versus asymptomatic crewmembers. Variability in crewmember training and flight experience may explain some of the differences observed.