HUMAN BODY IN SPACE--"How will the human explorer fare in his spaceship? Weightlessness evokes a pleasant picture--to float freely in space under no stress at all seems a comfortable and even profitable arrangement. But it will not be as carefree as it seems. Most probably nature will make us pay for the free ride. There is no experience on the Earth that can tell us what it will be like. It appears that we need not anticipate any serious difficulties in the functions of blood circulation and breathing. It is in the nervous system of man, his sense organs and his mind, that we can expect trouble when the body becomes weightless."