Specifications for Space

What were the airmen doing in the mountains? Late in July a seven-man team from the U.S.A.F. School of Aviation Medicine reached the rock-strewn slopes and box canyons of Colorado's Mt. Evans (14,260 ft.) and there staged some weird exercises. Led by a tall, lean and weathered man in Alpine shoes, long, green wool stockings and climbing knickers, the airmen went on ever-lengthening hikes (from 90 min. to ten hours), ran up and down the steep slopes above timberline, leaped from boulder to boulder. Purpose: Air Force wanted to know whether the human organism can be preconditioned for the peculiar conditions and hazards of space travel.

Pedal Away. Eagle-faced Dr. Bruno Balke, 51, who began his love affair with mountains while a surgeon with Hitler's Alpine troops, first led his team (one other doctor, five enlisted men) to Fairplay, Colo. (10,000 ft.), for hikes of up to three hours. Then he moved up 1.500 ft. to Hoosier Pass and laid on more hikes, extending eventually to ten hours (15 miles), plus intensive series of knee bends and sprints up steep slopes. By easy stages the team advanced to Evans.

Aside from its proud snowcap, the Mt. Evans summit boasts the Inter-University High Altitude Laboratory. There, climbers found a familiar piece of equipment: a massive, steel low-pressure chamber. Dr. Balke wanted to know whether his conditioned volunteers would be as subject to the bends and the chokes (painful, potentially fatal disorders caused by nitrogen bubbling out of solution in the blood) as a man zooming up from sea level.

The men were quickly run up to a simulated altitude of 38.000 ft., where the bends can be expected. They suffered none. Dr. Balke asked the men to do deep knee bends every three minutes (exercise speeds the onset of the bends, intensifies the pain). Still, most of them felt nothing. Physiologist Balke ordered five knee bends every two minutes. At this, most of the men felt twinges and began the descent to higher pressures.

But Master Sergeant Sam Karst, 34, from Greenville, S.C. kept going up. As the altimeter needle circled past the 50,000-ft mark, his eyes began to glaze, and the veins in his neck stood out like rawhide thongs. After 1 1/2 minutes at an empyrean 55,000 ft. (equivalent to as much as 7 1/2 miles above Evans' peak), Karst had had enough. Said he: "I could have stayed up longer, but I knew I was hypoxied,* so I signaled down."

Sneak Killer. Among other things that Balke & Co. studied was sensitivity to an excess of carbon dioxide in the inhaled air. Odorless and tasteless, COo can be a sneak killer: if something went wrong with his oxygen-recycling system or its indicator, a busy spaceman might not notice it until too late. In the altitude chamber, first Balke and then the airmen mounted an Exercycle. Disguised like Martians in a spirometer (breathing measurement) mask, they pedaled frantically off to nowhere.

With the oxygen circuit closed, and their metabolism rising with exertion, they sent the CO2 level soaring at a rate of 1% a minute (normal at sea level: about one-thirtieth of 1%). In ten minutes, the C02 level was nudging 12%. This .was about the limit. But Dr. Balke found that his conditioned subjects kept full consciousness longer than lowlanders. Also, they sensed more quickly (thanks to training) the reflexes that indicate the onset of CO2 giddiness. So they would have more time to do something about it. Aside from advantages in regard to the bends and CO2, Dr. Balke found that his volunteers, after conditioning, had a higher tolerance for oxygen shortage than at their San Antonio base (elev. 761 ft.). This meant that they could work efficiently at a consistently higher altitude. Furthermore, they could go still higher for emergency periods without ill effects.

What are the specifications for a spaceman? Dr. Balke and his crew supplied partial answers: he will be a lean, athletic type (bulging muscles are useless excess baggage), a scientist, and aged 35 to 45--men in this bracket have it over their juniors in greater emotional stability, endurance for tedious tasks, and better judgment as the result of longer training and experience.

* Space Age slang for feeling symptoms caused by hypoxia (insufficient oxygen).

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