Space adaptation syndrome

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. 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. Space motion sickness can lead to degraded astronaut performance. SMS threatens operational requirements, reduces situational awareness, and threatens the safety of those exposed to micro-g environments. Lost muscle mass leads to difficulty with movement, especially when astronauts return to earth. This can pose a safety issue if the need for emergency egress were to arise. Loss of muscle power makes it extremely difficult, if not impossible, for astronauts to climb through emergency egress hatches or create unconventional exit spaces in the case of a crash upon landing. Additionally, bone resorption and inadequate hydration in space can lead to the formation of kidney stones, and subsequent sudden incapacitation due to pain. If this were to occur during critical phases of flight, a capsule crash leading to worker injury and/or death could result. Short-term and long-term health effects have been seen in the cardiovascular system from exposure to the micro-g environment that would limit those exposed after they return to Earth or a regular gravity environment. Steps need to be taken to ensure proper precautions are taken into consideration when dealing a micro-g environment for worker safety. Orthostatic intolerance can lead to temporary loss of consciousness due to the lack of pressure and stroke volume. This loss of consciousness inhibits and endangers those affected and can lead to deadly consequences. Your body just isn't built to deal with zero-gravity. But there's no way of predicting how someone will handle it. Someone who gets car-sick all the time can be fine in space - or the opposite.