Answer:
Lack of oxygen
Decompression sickness
temperature variation
lack of gravity
Cosmic radiations hazards
motion sickness
Step-by-step explanation:
When an astronaut travels in the space he is aware of the challenges he might face during his journey. There are various test and rehearsals of travelling before a final travel takes place. An astronaut goes through many challenges which includes lack of oxygen supply, decompression and motion sickness. There is no gravity in space so an astronaut will have to be aware of the difficulties he might face during his travel. An hour on earth is 7 years long in space, so an astronaut should have patience and be able to deal with time variation.