The Vertical Frontier
NATURE designed man's body for a groundling's life, never more than treetop height above the earth's surface. In the upper reaches of the atmosphere or in the airless space beyond, man is as much out of his element as a mackerel marching across the Sahara. But unlike the mackerel, man is determined to transcend his environment. He reaches for the stars. A short half-century after the Wright brothers skittered over the sand dunes of Kitty Hawk aircraft now on the designers' boards will fly at heights of 100,000 to 125,000 ft. Man (Major Arthur Murray) has already flown up to 90,000 ft. and at 2½ times the speed of sound. Rockets have gone up 250 miles at speeds up to 3,600 m.p.h., and two rhesus monkeys (named Pat and Mike) have survived the ordeal of being rocketed up to 190,080 ft., are thus the current holders of the world's altitude record.
Man's body puts sharp limitations on how high he can go and how fast he can be accelerated to supersonic speeds. He has reached what Space Physiologist Hubertus Strughold aptly calls "the vertical frontier." To help conquer the frontier is the task of a young and bustling specialty: aviation medicine.
Most active in the field is the U.S. Air Force, which made great strides under its longtime surgeon general, Major General Harry George Armstrong (since July, surgeon of U.S. Air Forces in Europe). Just as busy on a smaller scale is the Navy, with most of its air-medical research directed the by top U.S. Captain Ashton Graybiel, one of the top U.S. heart experts. Scores of university laboratories are helping the armed forces. Eager researchers are using themselves as guinea pigs for experiments in low-pressure chambers, on high-speed centrifuges and rocket-powered sleds. They are toiling up the Andes to find out how Peruvian Indians stand the strain of high altitude, breathing radioactive gases, and sweating in 122° chambers on low oxygen.
The Dangers of Altitude
The researchers' first problem was to find out in detail what happens to the human body during an ascent, and why Aviation medicinemen now give this picture of men at steadily increasing altitudes:
Sea Level to 8,000 Ft. In a moderate-paced climb, the human machine does all right if no great demands are made on it. At this level, most flyers feel nothing more than a ping in the ears.
10,000 to 18,000 Ft. The field of vision narrow's, so the armed forces require all flyers to breathe extra oxygen above 10,000 ft. in daylight (above 5,000 in darkness). Up to 15,000 ft., most flyers remain conscious without oxygen, but their working efficiency is reduced. After 15 minutes to an hour at approximately 18,000 ft., nearly all (unless acclimatized like Alpinists) lose consciousness. But before a man does so, he may have strange delusions. Classic example: a reconnaissance pilot in the western Pacific in World War II refused to bother with oxygen and thought he was taking magnificently daring pictures of enemy positions. It turned out that instead he had urinated into his camera. Says General Armstrong, soberly: "A man is not himself when he is suffering from oxygen lack, even when he believes he is."