Space adaptation syndrome

Space adaptation syndrome
NASA astronauts acclimating themselves to space adaptation syndrome in a KC-135 airplane that flies parabolic arcs to create short periods of weightlessness.[1] In about two thirds of the passengers, these flights produce nausea,[2][3] giving the plane its nickname "vomit comet".
Specialty	Space medicine
Prevalence	50% of individuals

Space adaptation syndrome (SAS) or space sickness is a condition experienced by as many as half of all space travelers during their adaptation to weightlessness once in orbit.^[4] It is the opposite of terrestrial motion sickness since it occurs when the environment and the person appear visually to be in motion relative to one another even though there is no corresponding sensation of bodily movement originating from the vestibular system.^[5]