National Academies Press: OpenBook

Visual Problems of Space Travel (1962)

Chapter: Visual Problems within the Space Vehicle

« Previous: The Visual Effects of Weightlessness and Simulated Gravity
Suggested Citation:"Visual Problems within the Space Vehicle." National Research Council. 1962. Visual Problems of Space Travel. Washington, DC: The National Academies Press. doi: 10.17226/18422.
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Suggested Citation:"Visual Problems within the Space Vehicle." National Research Council. 1962. Visual Problems of Space Travel. Washington, DC: The National Academies Press. doi: 10.17226/18422.
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Page 21
Suggested Citation:"Visual Problems within the Space Vehicle." National Research Council. 1962. Visual Problems of Space Travel. Washington, DC: The National Academies Press. doi: 10.17226/18422.
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Page 22
Suggested Citation:"Visual Problems within the Space Vehicle." National Research Council. 1962. Visual Problems of Space Travel. Washington, DC: The National Academies Press. doi: 10.17226/18422.
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Page 23

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Visual Problems within the Space Vehicle In any vehicle, whether it be an automobile, train, aircraft, or space ship, certain information is required by the operator in order to effect successful control. ". . .Instrument display problems as such are not novel. In space flight ..." however, the absence of gravity, the presence of various accelerative forces, and other unique features of space pose certain display problems which are novel. The following paragraphs contain brief discussions of some of these problems. "Frequently, techniques for the visual communication of information in a terrestrial environment are to some extent dependent upon orientation of the display with re- spect to the vertical. Even more often, the orientation of the display with respect to the position of the observer it of importance. It is often true that instrument indi- cators and printed material sometimes may be interpreted with the observer in any relative position, but interpre- tation is accomplished only with difficulty and with a con- siderable increase in the probability of error when the orientation of the observer with respect to the display is not the usual one. Much of the difficulty which is en- countered may be attributed to conventional training and experience. In a spacecraft there will be long periods in which there is no acceleration and consequently no "up." It may prove undesirable or impractical to design the interior of a space vehicle, particularly if there is more than one man in the crew, so that there is any consistent visual "up." [in such instances,] it may be necessary to design visual displays so that they can readily be inter- preted by an observer in any position with respect to the display. This will require that all information in the dis- play be dependent upon relationships among elements of the display itself without relation to any part of the back- ground or surround. Individual elements within the dis- play must have unique, recognizable characteristics which are independent of their position. It will be necessary to conduct extensive training of crew members so that they can discriminate relations within the display for any dis- play orientation. Visual coding by color and shape factors which are independent of position will be of importance." 20

On the other hand, it may be desirable for psychological reasons to maintain a display design similar to those utilized in aircraft and aboard ships. As was discussed earlier, visual orientation during weightlessness is influenced markedly by the wearing of magnetic shoes (Simons, 1959). In such cases, "down" is where the feet are. Although this is not simulated gravity, and the individual can still walk on the ceiling as easily as on the floor, a display system which is designed within a fixed set of coordinates may be of tremendous psychological advantage. Not only would it permit the astronaut to live in surroundings of a more conventional nature, thus reinforcing hia psychological stability in a stressful situation, but the probability of operational errors would be less. Regardless of whether the information required by the astronaut is displayed in a conventional manner or in a novel arrangement, there may be certain instances in which it is desirable to have a particular display which maintains a constant orientation irrespective of the position or location of the observer. One means of accomplishing this is for the display to be attached to the observer. Cathode-ray tube development is such that miniature tubes (less than 1 inch in diameter) are readily available which have a resolution factor of 500-1,000 lines per inch. Such a tube in conjunction with a lightweight optical system can be mounted easily on the head. This system would permit the dis- playing of any type of information which can be shown in a conventional console with the added advantage of a constant orientation with respect 21

to the observer regardless of acceleration, weightlessness, or angular rotation. A working prototype of such a Bystem is presently undergoing evaluation in an industrial laboratory (Hall 8c Miller, 1960). "The exact nature of the visual displays utilized in a space ship will depend on precisely what operations man is expected to perform. . .[during] a given mission. . . . [The mission will, of course, ) determine the nature of information which. . .will [be required], A statement . . .[as to what the required information will be, therefore, must wait until specific missions are decided upon.] Cer- tain general questions may be posed, however, such as whether or not the man will be required to conceptualize his vehicle situation in such a way that he can explicitly state navigational problems and generate solutions for them in terms of available information, or whether all of his problem solution efforts will be in terms of the use of formulas, the bases for which he is not required to under- stand. The answer to such a general question as this will lead to more specific questions such as whether or not pictorial displays may be useful in the presentation of in- formation. It seems probable that in certain., .[domains] it will be impossible for a man to interpret information which he receives by direct external vision or from a pictorial type of information presentation. In other situ- ations such as the terminal stages of a soft landing, direct or synthetic pictorial information may provide a [ satisfactory ] basis for rapid analysis of the situation by a man. The kind of information necessary for the understanding of a complex situation which is unique in terrestrial experience poses an interesting problem in the subject of complex perceptual processes. Nonlinear displays and other relatively novel display characteristics should not be overlooked or neglected in attempting to find an adequate solution to.. .[such problems]." "The problem of orientation in a spacecraft will depend primarily on visual cues in the absence of reliable vestibular, . . .tactual, and kinesthetic cues which are dependent upon a gravitational field." There- fore, the engineering design of the display system must be such that the visual system is utilized optimally. As a result of the perceptual illusions discussed earlier, there will sometimes be, as in conventional 22

flying, marked conflicts between what the astronaut "feels" and what the instruments tell him. A very interesting study along these lines was made by Johnson and Williams. It was concerned with the relationship between the degree of confidence with which a person accepts the information provided by his visual field and his perception of motion direction. It was found that "destroying a person's confidence in what he sees does make a difference, at least in this situation, in whether he responds on the basis of visual cues or on the basis of some other available cues, presumable vestibular and kinesthetic (Johnson k Williams, 1949)." It waa found further that the more realistic a display, the more it waa relied upon by observers. It is, therefore, extremely important to design the display systems in space vehicles so as to maximize the probability that the user will rely on it rather than on physiological cues which in many instances are erroneous. Even though the man may be well aware of theae conflicts as a result of training, he will need to be reassured constantly as to the true state of conditions both inside and outside the ship. In such a ay stem quick readout facilities will be essential. In addition to the conventional display requirements there are numerous novel aspects of-space flight which must be displayed; i.e., ecological systems, unique navigational problems, radiation levels, computer readouts, etc. These factors have been discussed in detail elsewhere (Hopkins, Bauerschmidt, &t Anderson, 1960; Kahn, 1957) and hence are not reiterated here. It would seem that although most 23

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A variety of sensory and perceptual problems will arise in connection with space flight, both for the occupants of space vehicles and in certain instances for support personnel. The solutions to these problems are interrelated and tremendously complex, thus requiring cooperative efforts among many scientific disciplines.

Visual Problems of Space Travel discusses the problems of space flight as they relate to the visual mechanism. This book updates the National Research Council report Sensory and Perceptual Problems Related to Space Flight, and presents additional information regarding specific critical visual problems, as well as a recently compiled, extensive bibliography of research in this file.

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