National Geographic : 1989 May
At first it was great fun. But after 33 times and a little over ten minutes of weightlessness, I was disoriented and nauseated. MORE SERIOUS damage to the body comes from prolonged absence of gravity. We have learned much about this from the often painful experiences of Soviet cosmonauts, unrivaled for long-duration sojourns in the punishing world of zero g. His first night aloft Oleg Atkov drifted un easily through the space station Salyut 7. Sleep was impossible. His head, accustomed to its own weight on a pillow, felt large and light. His face was bloated with blood that, no lon ger held in his legs by gravity, had migrated upward. When he closed his eyes, he felt as if he were spinning, since without gravity his inner ear could not sense up and down. Without intending, Atkov, a cosmonaut physician, was serving as a test subject for another of Albert Einstein's contributions to science: the principle of equivalence. It states that there is no difference between the effect of gravity and that of acceleration; they are equivalent. Thus a person falling will not feel his own weight, an idea that helped lead Einstein to his grand theory of gravity general relativity. An orbiting space station, like the moon, continuously falls toward earth. Only its forward motion prevents it from crashing. To Atkov the effect was the same as being inside a freely falling elevator. Atkov's body reacted profoundly. His muscles, which were no longer needed for supporting his body or lifting things, atro phied rapidly, despite intense exercise each day. "I could see them wither before my eyes," said the amiable cosmonaut when I vis ited him in Moscow. Atkov's bones, similarly underemployed, insidiously gave up calcium and lost density. "I became lethargic and fatigued, far worse than I had expected." When he landed after eight months in space, he was so weak he had to be carried on a stretcher. He called his one trip to space "more than enough." Medical researchers are worried about a tentatively planned trip to Mars, taking as long as three years round-trip.* Dr. Harold Sandler, a NASA aerospace physician at Ames, wonders: "Is there a point in sending * See "Mission to Mars" by lunar astronaut Michael Collins in the November 1988 issue.