Symptoms and signs of space motion sickness and fluid shift were observed by 4 specially trained crewmembers on the physically demanding 10 day flight of Space ShuttleSpacelab 1 launched on 112883. Anonymous but detailed firsthand reports are presented. Three crewmen experienced persistent overall discomfort, and vomited repeatedly. Symptom pattern was generally similar to that seen in the individuals preflight, except that prodromal nausea was brief or absent in some cases facial pallor and cold sweating were usually absent one subject experienced uncomfortable stomach elevation. However, symptoms were clearly modulated by head movement, were exacerbated by unfamiliar visual cues, and could be reduced by physical restraint providing contact cues around the body. Drugs known to be effective in preventing motion sickness were judged helpful in limiting symptoms, including vomiting. Results support the view that space sickness is a form of motion sickness.