Weightless in Space

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Before the flight, biologists removed the inner ear sensory system of one of the mice, left the other normal, and put each in a "compartment in a rotating smooth-walled drum with an irregularity that afforded a possible foothold for each." Cameras recorded the brief critical no-gravity point of the rocket flight: the desensitized mouse clung to his perch, "whereas the normal animal clawed at the air, suggesting disorientation." A subsequent experiment with monkeys "clearly established the fact that the weightless state itself produces no disturbance of circulation in terms of heart rate or arterial and venous blood pressures," says Major Simons. "This does not mean that the circulation might not be involved secondarily due to emotional and autonomic reactions to weightlessness.

Such reactions are essentially the same whether caused by weightlessness, a rough sea or an obnoxious mother-in-law." Inside Problem. Generally, the experiments indicate that a human who can see or touch something to orient himself will be able to fight down the warnings from a sensory system gone haywire in weightlessness (much as a pilot learns to fly his airplane by what his instruments tell him even though this contradicts what his balance system tells him). Scientists are not yet clear what may happen without any touch or sight reference—for example, to a man inside a free-floating space ship, says Major Simons, "indications are that severe disorientation can occur." Nevertheless, he concludes, accumulating evidence indicates that man can learn to get used to the sense of floating or falling, and master his reactions sufficiently "to avoid an attack of incapacitating space-sickness."