Summary Session, 19 February 1957
Human Factors PanelParticipants and Their Topics
Hubertus Strughold (Panel Leader), Chief, Dept. of Space Medicine, USAF School of Aviation Medicine, Randolph Air Force Base, Texas
Col. Paul A. Campbell, Special Assistant to Commander for Medical and Bioscientific Research, Air Force Office of Scientific Research
"Human Logistics in Air Travel"
Maj. Stanley White, USAF, Wright-Patterson Aero Medical Center, Dayton, Ohio
"Maintenance of Pressure Conditions at Extreme High Altitudes"
Hermann J. Schaefer, Naval School of Aviation Medicine, Pensacola, Florida
"Appraisal of Cosmic Ray Hazards in Extra-Atmospheric Flight"
Maj. David G. Simons, Chief, Space Biology, Aeromedical Field Laboratory Holloman Air Force Base, New Mexico
"Several Techniques for Conducting Space Biology"
George T. Hauty, Dept. of Experimental Psychology, USAF School of Aviation Medicine, Randolph Air Force Base, New Mexico
"Fatigue Confinement and Proficiency Decrement"
Andrew G. Halley, Chairman of the Board, American Rocket Society, Washington, D. C.
"The International Situation and Legal Involvements with Respect to Long-Range Missiles and Earth-Circling Objects"
Dr. von Karman:
We come now to the last subject-it is Human Factors-or you can say, Aero- Medicine. I enjoyed very much these films on our animal kingdom. It reminded me of an old story; like my friend Bill Bollay, I also read old magazines and books. I don't know whether you remember that the doctors were very much worried after the first balloon flight in the 18th Century. It was the dangerous altitudes because the balloons went to five, six, eight-thousand feet-not higher than the highest mountain-but anyway they also used the perso~eolf the animal kingdom. They put a goat, a hen, and a duck in the basket that went up with the balloon. When they came back, the goat was all right, the duck was alive, but the hen was in a pitiful state. The French head of Aeromedicine got into a big investigation as to what is the difference in the body structure of the hen and the duck which makes the duck resistant to altitude and the hen not. Well, the boy who was in charge of the animals found out that during the flight the goat had attacked the hen . . .
Hubertus Strughold :
Dr. von Karman, Ladies and Gentlemen:
In the introduction address of the Human Factors Panel, I took the opportunity to make a few remarks about terminology and the various kinds of space operations considered under the aspect of the human factors involved. Some terminological remarks seemed to me appropriate in such a novel and fast growing field such as astronautics, especially since in medicine and biology we have a terminology and a way of thinking sometimes very different from that of the astrophysicist and the engineer. A discussion of the problems of astronautics on a common platform like this should be very fruitful because the different terms and aspects may supplement each other and thus contribute to the clarification of the issues in question.
Astronautics – in a broader sense – can be defined as the science or art of the design, production, and operation of a space craft. If we wish to emphasize the human factor involved, bioastronautics would be an appropriate term. In space medicine or space biology, a branch of aviation medicine, we study the whole complex of bioastronautical problems. That field which studies the ecological conditions on planets is called planetary ecology or astrobiology.
An especially good example for the specific aspects of space medicine is the analysis of the atmosphere. The astronomer sees the end of the atmosphere at about 600 miles where it ceases to be a material continuum. From the standpoint of human flight, it is a series of functional borders beginning as low as 63,000 feet and ending with the final functional border around 120 to 140 miles, that determines where space begins for the flyer. Actually, we use the term space equivalence for the regions which show space conditions but still lie within the atmosphere, as it is astronomically defined. The area above 63,000 feet is partially space equivalent progressing step by step to total space equivalence around 120 to 140 miles if we ignore some environmental properties caused by the proximity of the solid body of the earth. At this last level the laws of aerodynamics lose their meaning and those of celestial mechanics (or astrodynamics [Romick]) become fully effective. AU this is important for us because the planes of the century class and the X class operate in regions where space and atmosphere overlap. We are, therefore, at present in the developmental stage of space equivalent flight, the first phase of space operations. The record flight of Capt. Iven C. Kincheloe can be classified as a local space equivalent flight, the precursor of eventual long distance space equivalent flights in rocket liners or gliders. These flights lie in the border field between aeronautics and astronautics with definite features of the latter.
Now just as we recognize certain boundary lines within the atmosphere, indicating where space equivalence and space begins, in extra-atmospheric space too the astronaut needs some demarcation lines or subdivisions for the classification of true space operations. We need a topographical description of Space, something that – in analogy to geography – we might perhaps call Spatiography. For a subdivision of space, we can use the orbits of the moon and of the planets (cislunar and translunar Space, cismartian and transmartian Space) as Krafft Ehricke has suggested. Furthermore, he calls the area around a planet which shows some peculiarities caused by the mere presence of that body and some of its activities, planetary space.
We may still go a step further in the subdivision of space using the gravitational attraction of the celestial bodies. The astronomer is interested in the gravitational fields between celestial bodies to explain the laws of their motions and the occurrence of perturbations. For the astronaut it is the sphere of gravitational influence or more precisely, the sphere of predominant gravitational attraction. And here the rocket and fuel engineer is interested in the energy required to project a vehicle into orbits within this sphere of gravitational influence or to overcome it, in other words, to escape from it and to fall into other spheres of predominant gravitational attraction. The actual astronaut in charge of the operation is interested in their spatial extension and the time element involved in the operation. So is the specialist in the human factors. From the standpoint of astronautics and bioastronautics it might be practical to call these spheres of predominant gravitational attraction simply "Gravispheres," which term implies or emphasizes the spatial and temporal element. There is first the giant gravisphere of the Sun which blends far beyond Pluto with the gravitational no-man's-land between the stars. Within the Sun's sphere of gravitational influence move the planets with gravispheres of their own and within these are found the gravitational provinces of their moons.
Based on this kind of topographical description of the space in our solar system and on a space medical analysis of the atmosphere, the following kinds of space operations must be considered: Space equivalent flights, satelloid flights and satellite flights, lunar operations of several varieties, and finally inter-planetary space travel. It is advisable to use for this final phase of space operations, the word travel, and for this phase only.
These introductory remarks may serve as a frame of reference for the various topics of the panel. These were the highlights:
Let's begin with the medical problems in the area of space equivalent flights. In his paper, the problems of space equivalent test program, Major Stanley White, Aeromedical Laboratory, Wright-Patterson Field, pointed out that two major areas in astronautics are presently underway in the world. In one area, the engineers are working on the vehicle problems and the fuel problems; in the other area, there is an equally large group of practically all disciplines of scientists attacking the problems of preparing man to meet space flight.
Preparing man is complicated by the fact that basic data which can be used as building blocks for experimental testing and design are still being obtained. Equipment and instrumentation needed to obtain data and perform groundwork for programs at safe and attainable altitudes are complex and time consuming for design and construction. Finally, the value of a well planned program and the team concept in meeting this problem area was discussed, using as an example an ascent in a low pressure chamber to an extremely high altitude. It was Major Arnold G. Beck's chamber flight or ascent to 198.7 thousand feet which was the culmination of the team concept in action. The actual successful conclusion of this experimental program of exposure of men to a space equivalent height took approximately six months of progressive study and smaller experiments. The team that affected the conclusion of the program numbered about 35 to 40 people each contributing his specialty whether it be electronics, materials, biologic information, or engineering.
In the space equivalent region of the atmosphere, cosmic ray particles attract our medical interest. Dr. Hermann Schaefer from the U. S. Naval School of Aviation Medicine, Pensacola, Florida, in his paper "Appraisal of Cosmic Ray Hazards in Extra Atmospheric Flight," pointed out that cosmic ray primaries have been shown to produce severe damage on the cellular level. How far this local injury will produce a general reaction in organism depends on the frequency of hits. Fairly accurate data on this frequency are available only for balloon altitudes. For the fully extra-atmospheric region, not even informed guesses are possible.
Recent observations during a giant solar flare has established that the Sun at that time was responsible for a 35 fold increase in cosmic ray particle intensity and contributed protons of at least 30 billion electron volts energy. This unexpected finding shows how limited is our present knowledge of the cosmic ray phenomenon. A better appraisal of the cosmic ray hazards to man requires elaborate experimentation with artificial satellites to study both the extra-atmospheric intensity of the heavy component and the reaction of test animals to it, and also extended studies concerning abnormal activities of the Sun. If a statement is to be made at the present time of insufficient knowledge as to the damage from the dense ionizations of the primary cosmic radiation to the human organism, one could say-according to Dr. Hermann J. Schaefer-that this damage, whatever its quantity, will not be dramatic or conspicuous or immediately apparent but will slowly develop into a delayed manifestation. It will have to be accepted as a calculated risk which is not likely to weigh heavily in short exposures, but might be substantial for prolonged exposures.
Major David G. Simons of the Space Biological Branch of the Aeromedical Field Laboratory in Holloman Air Force Base, New Mexico, too reported on cosmic radiation in his paper "Areas of Current Space Medical Research." He showed a movie of animal capsule and balloon flight techniques, illustrating procedures employed to expose experimental animals to primary cosmic radiation. These experiments have been conducted on balloon flights during the past five years. The animal capsules developed provided temperature protection and sealed cabin environment required to maintain mice, guinea pigs, pigs, monkeys and other animals at altitudes up to 125 thousand feet for periods as long as 30 hours on one flight. The 24 hours exposures obtained to date have demonstrated genetic changes in Neurospora (a fungus), and an unexpected susceptibility of the hair of black mice to heavy primary cosmic radiation. The effects observed following 24 hour exposures do not constitute health hazards, however they provide no positive information concerning more prolonged exposure, or exposure to additional sources of ionizing radiation.
Furthermore, Major Simons reported on sealed cabins. Such cabins, as you know, are necessary at about 70 to 80 thousand feet. The problems encountered in providing a sealed cabin atmosphere for the animal capsules for a period up to 30 hours led to an investigation of sealed cabin atmospheres such as would be suitable for manned satellites. Winzen Research, Inc., Minneapolis, Minnesota, determined that optimum weight efficiency for carbon dioxide and water vapor absorption was obtained with lithium hydroxide and lithium chloride respectively. The problem of suitable pressure, and also the fire hazard were discussed. The temperature control problem that was found to exist for the animal capsules floating for 24 hours above 100 thousand feet is considered directly comparable to that which would be encountered in a manned satellite. At this high altitude, less than one percent of the atmosphere remains, so that essentially all heat exchange with the outside occurs by radiation.
Finally, Major Simons discussed the problem of re-entry. Three aspects of re-entry into the atmosphere are of particular medical interest: (1) the safe recovery of recorded data from an ICBM or satellite carrying biological material; (2) the human factors aspects of re-entry into the atmosphere from flight beyond it – in terms of heat – acceleration and performance capability; (3) the question of what escape concepts are valid beyond the atmosphere and/or at orbital velocities. The first step toward experimental investigation of these problems is being taken by dropping test objects such as ejection seats, and capsules from balloons floating at about 90,000 to 120,000 feet.
Turning now to space operations of long duration such as manned satellite flight and lunar and planetary operations, Colonel Paul A. Campbell, Special Assistant to the Commander of the Office of Scientific Research, Washington, D.C., in his paper "Human Logistics Prom The Viewpoint of Space Travel" explained that in the consideration of human logistics, we must start somewhere and at present, the best example involves the satellite.
To launch the satellite weighing approximately 21.5 pounds into its orbit, approximately 22,000 pounds of fuel and structure are required of the launching rockets. Thus, about a thousand pounds of fuel and structure are required for each pound of payload.
Although one certainly cannot and should not extrapolate data concerning the satellite into that of a manned space vehicle, certain logistics are brought into light by these figures for each pound of man, food, oxygen, water, protective equipment, and air and environmental conditioning will cost hundreds or thousands of pounds of launching weight, unless some exotic type or propulsion is devised.
The weight of the average U. S. Air Force pilot is in the neighborhood of 163 pounds. He consumes something in the order of two pounds of oxygen per twenty-four hours, something in the neighborhood of four pounds of food and a similar weight in fluid. These are quite rough figures and vary with activity, temperature, both body and ambient, metabolic rate and a host of other factors. These figures do not include clothing, packaging of food and fluid, protective and conditioning equipment. They do, however, point out the magnitude of the logistic problem in terms of requirements for lift.
Thus, so far as human requirements are concerned, if space flight is to be achieved, there must be a general rule that energy, protection, etc. must be supplied at minimum weight, in minimum volume, and then if consumed, utilized at the lowest consumption rate consistent with the job needs. Consequently, miniaturization for volume, minimization for weight and the multiple use of things must be practiced. These precepts must be kept constantly before us.
At present – Dr. Campbell continued – scattered among many disciplines such as aviation medicine, physiology, the sciences of nutrition, metabolism, anthropometry, etc., there is existent almost all of the knowledge one would need for selection and support of a man or a crew of men on flights above the atmosphere for short periods of time. If days were involved rather than hours, then a knowledge gap would occur in the science of sealed cabin ecology as there is no simple solution for the problem of placing a man or a crew in a closed regenerative system which would allow his metabolic byproducts to be cleansed, altered and reused without weight and volume costs which are prohibitive – at least so far as present propulsive systems are concerned.
The selection and proper application of the bits and pieces of existent knowledge would depend upon the mission, the most important factor probably being duration.
Consequently, it seems that the time is now ripe to stop thinking in terms of generalities and focus on specific requirements. For this purpose I would like to suggest a sort of interdisciplinary exercise selecting, let us say, three levels of mission, then asking the designers and engineers to give those of us in human factors a frame of reference in which to establish exact requirements, apply existing knowledge and look for knowledge gaps. The first level might be a flight to, say, an altitude of 200 miles and return. A second level of mission could, for instance, emulate the satellite but be manned. The duration could be, say, one hundred trips around the earth and return. The third level could possibly be a flight around the moon.
After the engineers and designers have given us our frame of reference for each of the levels which should include duration, available crewspace and weight allowances, etc., working groups could be formed of those experts in the sciences of aviation medicine, physiology, psychology, human engineering, metabolism, nutrition, sanitary engineering, etc., who could under direction establish requirements, assemble the required knowledge and point out knowledge gaps where gaps exist. A series of alternatives could then be returned to the engineers for sorting and selection.
Such an exercise, says Colonel Campbell, would broaden the scientific base of those interested in our problems and would most certainly bring forth considerable new knowledge.
Protective and survival gear at present require excessive weight and volume, however. All of the great frontier crossings of history have been made on this basis of acceptable calculated risk and the space frontier will be no exception. On this basis and through careful selection and consideration of survival and protective equipment, much weight can be saved.
In his paper "Fatigue, Confinement, Proficiency, and Decrement," Dr. George T. Hauty from the Department of Psychology, School of Aviation Medicine, Randolph Air Force Base, Texas, reported that in a study designed to appraise certain effects of dextroamphetamine (a drug which counteracts fatigue) subjects were trained on a task which consisted of monitoring several simulated aircraft indicators and upon the detection of departures from null, executing corrective action. Experimental treatment began at 0900 in the morning and following this the subjects were required to perform the task for 30 consecutive hours. With exception of very short and infrequent periods for meals and exercise, the subjects were confined within their cockpit and were not permitted to sleep. It was found that: (1) initial level of proficiency was maintained up to 2400 hours at which time decline set in and progressed until about 0600 hours. At this point proficiency began to increase until 1200 hours and to the termination of work, proficiency was one-half that of initial level; (2) dextroamphetamine exerted a substantial restoration of proficiency and with no evidence of a let down effect; (3) nearly all subjects reported perceptual delusions and hallucinations ranging in degree of bizarreness and adverse effect upon proficiency. Since these operations occur with a normal sensory environment, it may be that such will occur to a greater degree in a dosed ecological system associated with sensory deprivation as it is found in space flight, with nullified gravitation, in a hermetic cabin, surrounded by the perpetual silence of space.
The human factor is closely related to law. In our human factors panel, therefore, Mr. Andrew Haley from Washington, D.C., a permanent member of the Directors Board of the American Rocket Society, gave a discussion about current international situation and the legal involvement with respect to long range missiles and earth circling objects.
Space law includes a number of aspects, for instance, sovereignty over the air space and free space. Space law also regulates the relations between terrestrial people meeting each other on other celestial bodies. A branch of space law, called Metalaw regulates the relations between terrestrial creatures and creatures on other planets. Concerning the fundamentals and details of Space law the reader is referred to papers recently published by Mr. Haley in the Journals "Jet Propulsion" and "Astronautica Acta."
This is the summary of the highlights of the Human Factors Panel. The problems in space medicine or bioastronautics are numerous and the topics discussed at this panel are only a few examples. Much work has to be done, especially in the field of cosmic rays, vacuum pathology, human engineering of the space cabin, experiments in space cabin simulators, psychological problems in closed systems, the use of plants for the climatization of such systems, the state of weightlessness, visual problems in space, day-night cycling in an environment where there is no day and night, launching, atmospheric entry and a happy ending. Nevertheless, I would like to conclude this report with the statement that the human factor is very probably not an absolute limiting factor for astronautics, but rather a modifying factor and this is encouraging for all of us working together on this grand project of our century or rather of our millennium. Thank you very much.
Herb Seaton – Convair
Q. In connection with the reduced sensible gravity that would be apparent when you are out in space, there have been some questions raised at times as to whether or not this was going to cause a loss of equilibrium, etc., in a human being. Has there been any indication resulting from research that this may be something that could be overcome by the human being becoming accustomed to low levels of gravity, or does it appear that this disorientation will continue down to low levels?
A. There are studies in this respect presently underway at Holloman Air Force Base by Major David G. Simons and also Dr. Siegfried J. Gerathewohl of the School of Aviation Medicine, USAF, at Randolph Air Force Base, Texas. They use for these experiments, parabolic maneuvers in jets. At the present time, in this way we can produce the state of weightlessness for about thirty seconds, and studies have been made with regard to the tolerance to weightlessness and also with regard to the capability of muscular control, by aiming tests, etc. So far it has been found that the subjects can adapt themselves very quickly to this state of weightlessness in aiming tests. And finally it has been found by Dr. Gerathewohl in a great number of parabolic flight maneuvers, that about 25 percent get nauseated, about 25 percent are indifferent to the state of weightlessness and the majority even enjoy it. A report has been given in Rome at the meeting of the International Astronautical Federation in 1956 and has just been published in the Journal "Acta Astronautica." At the present time we can produce the state of weightlessness for only about thirty seconds. In some newer planes in the next few years, we might be able to produce it for several minutes and then we will have perhaps a better idea about this question. But to study the tolerance to weightlessness for prolonged lengths of time, we need manned artificial satellites.
Duvall - from Wright Field
Q. Not so long ago in a popular magazine, I read about some explorations in the Mediterranean by a Frenchman who rode a specially designed horse under conditions which because of water buoyancy in some respects simulated weightlessness. What would the significance of that be in your opinion?
A. A very interesting question! I would like to say this. For the perception of our position in space we not only have the so-called otolith organ in the inner ear, we have also a great number – about a half-million – receptors in our skin, the so-called pressure receptors, or sometimes called tango-receptors. And we have specific nerve endings in our muscles especially in the anti-gravity muscles, and also receptors in the connective tissue around the muscles, all of these are called mechanoreceptors, or peripheral mechano-receptors. Now, when I stand here or when I walk, the contact area between my body and the ground is very small; for this reason the pressure upon the skin is very high and I get very strong pressure sensations from the skin of the soles of my feet which are utilized for the coordination of my movements and for the perception of my position. When I am in water, up to my neck, not moving, floating not swimming, then the contact area between the supporting medium and my body is very large and stimulation of the presso-receptors therefore is very low and the sensations may remain below the threshold of perception. By this reason the condition between floating in water and weightlessness in space operations, are similar, but only with regard to the sensations from the peripheral mechano-receptors. The otolith organ is under the same pull of the gravitational force as it is normally on the ground. Major Leon A. Knight USAF (MC) at the School of Aviation Medicine at Randolph AFB, Texas, has recently finished studies in a swimming pool about this question in various body positions and will report about this at the AeroMedical Meeting in Denver, Colorado, 6-8 May 1957.
Jim Drake – Marquardt Aircraft Co.
Q. I had one interesting thought, Dr. Strughold, as you were summarizing the influence of the man on the design of the space ship. You indicated that it would be a modifying factor. I was reminded of some of the propulsion systems that were suggested by Dr. Bollay's panel, a large number of them which involved nuclear propulsion. I also recalled the three hundred days or so of exposure going out and another three hundred days or so coming back, and I wondered whether the shielding required in the space ship wouldn't become more than just a modifying factor under these circumstances?
A. With regard to cosmic rays it was pointed out by Dr. Herman Schaeffer that probably a two inch thick layer of aluminum would be necessary to shield the men against cosmic rays. The final word has not been said in this respect, but perhaps I should make a concession and say that it is a very heavily modifying factor.
Dr. Von Karman:
I also have to thank Dr. Strughold, not only for a very interesting presentation, but also the witty and competent remarks during the discussion. There does not remain anything else than to thank the audience; for it was a long session and the audience endured all the discussions with sensible interest, I hope. So I would like, after thanking the audience, to give the chair back to Dr. Alperin, representing here the organizing agents.