Humans in Space

Unmanned space flight is almost in the bag. Rockets have already risen to the edge of space, and no one in the rocket business doubts that unmanned satellites will soon be revolving on orbits around the earth. Manned space flight is much more difficult because of the vulnerability of human crews. Last week a symposium at the University of California discussed some of the problems.

The human body is adjusted to mild cosmic ray bombardment at the earth's surface, but no one knows what will happen to humans who spend considerable amounts of time above the sheltering atmosphere. At last week's symposium, Major David G. Simons of the Air Force's Space Biology Laboratory, reported that recent experiments have been somewhat reassuring. For five years Holloman Air Force Base, N. Mex. has been sending mice, guinea pigs and monkeys on 24-hour balloon flights. Enclosed in pressurized and air-conditioned capsules, the animals rise as high as 100,000 ft. Two of the monkeys have had 63 hours of flying time above 90,000 ft., where primary rays are rampant.

Genetic Damage. Their exposure to the cosmic rays did not seem to damage any of the animals. Some of the black mice grew a few white hairs, presumably caused when cosmic rays passed through hair follicles. No other bodily damage was noted. Major Simons admits, of course, that cosmic rays kill tissue cells, but he does not think any part of an animal's body is seriously damaged by the loss of a few cells. Genetic damage is another matter. If a cosmic ray hits a reproductive cell (sperm or ovum), it can cause the birth of an imperfect individual. Major Simons cannot guarantee at present that all his high-flying mice and monkeys will have normal descendants.

Less romantic than cosmic rays is the problem of food and air for space voyagers, but Dr. Nello Pace of the University of California considers the problem no less interesting. A normal man has a water turnover of about 5 Ibs. a day. Since the spaceship must conserve every possible ounce of weight, this water must be recycled: condensed from the air and extracted from urine and feces. Food cannot be recycled without making the spaceship a flying farm, and Dr. Pace is not even sure that preserved food will be satisfactory for a long voyage. No preserved ration, he said, has been developed that can be tolerated for more than a month or two without bad effects. So the spaceship may have to be big enough to carry frozen food lockers.

The spaceship's atmosphere is a problem too. Its oxygen will have to be replaced as it is consumed, and the carbon dioxide from the crew's lungs will have to be disposed of. Both jobs can be done at the same time by green plants, which separate oxygen from carbon dioxide. With this system in operation, the spaceship would be a miniature of the parent earth, where plants and animals, acting together, recycle the atmosphere.

The experts are not sure what the spaceship's atmosphere should be made of. Pure oxygen might be all right if its pressure were low enough (at atmospheric pressure, it is poisonous), but nitrogen also may be necessary for human health. In any case, the pressure in the spaceship should not be too low. If a meteor punctured the skin, a good thick atmosphere of oxygen diluted with nitrogen or helium would not be lost as quickly as a thin one of oxygen alone.

Zero Gravity. The most baffling puzzle of all is the effect that lack of gravitation will have on the crew. They will float around the cabin, of course, and will have to drink through straws instead of from glasses, but such things are minor. The major problem will be loss of orientation.

Humans have three orienting mechanisms: 1) vision, 2) the balancing apparatus in the inner ear, 3) the "kinesthetic" sense, which reports tension and pressure in the skin, muscles and viscera. All except vision fail when gravity falls to zero, and there is an excellent chance that vision alone cannot tell a man whether he is right side up. Special instruments may have to be developed to orient space crews artificially.

Zero gravity cannot be created on the earth, except momentarily, as in a stunting airplane. One suggestion for simulating it is to use a congenital deaf-mute with no inner-ear balancing sense and put him in a diving suit where he would be made "weightless" by the water's buoyancy. Under these conditions he will react like a man on a gravity-free spaceship. Another suggestion, which may be followed up by the Office of Naval Research: put animals on a merry-go-round that subjects them to double-strength gravitation. After they have become adjusted to life at 2 gs, they can be returned to normal at 1 g--and studied to see how the change affects them.

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