Air University Review, July-August 1968
Major General Charles H. Roadman
In this issue, Air University Review presents several aspects of aerospace medicine. First is an introductory overview by Major General Charles H. Roadman as Commander of Aerospace Medical Division, Air Force Systems Command. The succeeding articles deal with areas that are receiving intensive study because of their applicability to current and future USAF and NASA aerospace programs. Colonel Timothy N. Caris explains some of the techniques used in medical evaluation of astronauts and test pilots. Dr. A.A. Thomas discusses toxicology factors affecting occupants of closed cabins during extended space light. Dr. Hubertus Strughold sees a problem in man’s reactions to time cycles different from the normal 24-hour, day-night cycle. And Mr. James W. Brinkley describes the work in developing escape systems for aerospace vehicles.
Since man’s first feeble efforts to lift himself on fragile wings, medical men have had a part in his struggle to conquer aerospace. Military men had been flying only a few months during World War I when it was discovered that over half of all pilot casualties were directly attributable to the physical unfitness of the man for flying duty rather than to mechanical or other external causes.
Although the term “aerospace medicine” is relatively new, aerospace medicine
as a separate technical discipline began in
Aerospace medicine today encompasses specialty areas that did not exist fifty years ago, primarily because we did not know as much about the human body as we know today. The progress in aerospace operations has also resulted in physiological stresses being applied to the human body that could not have been foreseen fifty years ago. Both these factors have influenced the efforts of aerospace medical personnel. Most of the research work being done in aerospace medicine falls within three very broad categories: medical evaluation, environmental control, and physiological stresses imposed by aerospace operations.
The physical standards that were developed for the early aviator were considerably simpler than those used today. The earlier medical evaluation procedures were also less sophisticated. As we learn more about the human body and the physiological stresses imposed by contemporary aerospace operations, we are modifying our standards. In the process, we are developing completely new standards for the healthy human being. Traditionally, the health standards of this country have been derived from sick people, for they were the ones most in contact with the nation’s physicians. We are now dealing with very healthy people, we have amassed considerable information about their normal state of health, and thus we are establishing new health standards.
A case in point, during the past few years we have found that one of the peculiarities of an electrocardiogram tracing that had been thought to be indicative of heart disease is in fact benign. The result is that we have several thousand pilots flying today who might have been grounded because of their electrocardiogram interpretation a few years ago.
Another important facet of our medical evaluation program is that we are actually doing predictive medicine. The astronaut or aerospace test pilot who takes his initial medical evaluation today will not go into space for another four to five years. Our job is to predict his fitness at that time.
In the area of environmental control, AMD has for several years been involved in research to determine the best gaseous mixture and the best possible pressure for a specific space cabin on a given mission. In an effort to determine man’s ability to survive and perform normally in an atmosphere that can be provided by the engineers, some of our more comprehensive studies have required human volunteer subjects to remain in space-cabin atmospheres for up to sixty days. During this time we not only study their ability to survive and perform but also do detailed analysis of their bodies’ ability to metabolize certain space foods while in this environment.
We as a nation are becoming more and more conscious of the air we breathe and the possible contaminants that it might contain. It is important to realize, of course, that we are surrounded by and exposed to materials that were not even known fifty years ago, and some of the simplest of our everyday materials can become toxic in such confined quarters as a space cabin. AMD has expended a considerable amount of its resources in recent years to determine the toxicity of various materials in confined quarters and the possible effect of long-range exposure on the human body. These studies will provide some basic data to the nation’s clean air program.
Almost from the beginning, medical personnel have been concerned with the physiological stresses imposed by aerial flight on the human body. These stresses manifest themselves in many ways, and they become more important as our aircraft fly faster and higher. Escape from early aircraft was uncomplicated: the main problem was to push oneself over the side in such a way as to avoid the vertical or horizontal stabilizer. Escape from the aerospace craft of today and tomorrow imposes problems that make a “step over the side” impossible.
We are now flying at speeds and altitudes that compel us to resort to escape systems which, in themselves, impose physiological stresses that test the extremes of human effort and endurance. We have, for several years, studied these stresses individually. We have studied the effect of increases in the pull of gravity on the human body, the effect of a sudden change in atmosphere, sudden changes in temperatures, and even the effect of rotation in all axes. After studying these stresses individually, we have a pretty good idea of man’s ability to withstand each. However, when the stresses are applied simultaneously as they are in a real-time escape situation, these parameters for withstanding may not apply.
We are in the process of developing new devices to apply these physiological stresses in such a way as to duplicate almost any real-time escape situation from any type of aircraft or spacecraft. When perfected, the ability to do this will save untold dollars and possibly some lives by permitting us to experiment at lower levels of stress before duplicating a real-time escape environment where many factors may be unknown.
Although each of the component organizations of the Aerospace Medical Division makes a somewhat different attack on aerospace medical problems and each has its unique facility with which to work, all of them have one goal—to keep aircrew members functioning effectively and efficiently in their environment.
Aerospace medical personnel may seldom be seen in the forefront of development of aerospace systems, but they have played a key role—if backstage—in the development of every aircraft or space system in the last twenty years. Our business is to support the Air Force mission by insuring the health and welfare of Air Force personnel and their ability to perform, whether it be in an aircraft, on the flight line, in an underground silo, or in a spacecraft.
Aerospace Medical Division, AFSC
Major General Charles H. Roadman (M.D.,
Disclaimer
The conclusions and opinions expressed in this
document are those of the author cultivated in the freedom of expression,
academic environment of
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