Human performance capabilities in full pressure suits

Date

1971

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Abstract

The objectives of this study were: (1) To systematically quantify the functional reach and operational visual field capabilities for two conditions. The first was the nude man or unsuited condition. The second was the suited condition in which the subjects wore a series of different full pressure suits. (2) To compare the nude man capabilities with that of each pressure suit and to compare the capabilities of the different pressure suits. (3) To demonstrate the existence and efficacy of functional relationships empirically derived from observations of these capabilities. Functional reach capabilities for a group of seven, trained subjects were determined for the nude man condition and for each subject while wearing the Advanced Extravehicular Suit (AES), the Apollo A6L and Apollo A7L suits. Operational visual field was subsequently determined for these subjects for the nude man condition and for each subject while wearing the Advanced Apollo Suit (RX3A), the AES and Apollo A7L suits. This was accomplished for two vision conditions: head stationary; eyes stationary and head stationary; eyes moving. All suited measures were taken at the vented (0. 25 psig.), low (3. 7 psig.), and high (5. 0 psig.) pressure levels. Graphical representation and analyses of variance techniques, including Duncan's multiple range tests, were applied to both functional reach and operational visual field data; and the results of these analyses supported the following conclusions. For functional reach, it was seen that: (1) Functional reach capability is a complex capability involving maximum/minimum reach, distance, and range of motion differences. Relative to a given suit, functional reach values are dependent on these factors. Thus, the AES suit provides the superior maximum functional reach, and the A7L suit provides the superior minimum capability. In addition, the A7L suit evidences superior range of motion for both maximum and minimum cases. (2) The minimum case, rather than the maximum case, is the more critical index relative to suit comparisons, as an increase in pressure level produces a general decrease in performance. (3) The act of wearing a pressure suit,, even in the vented or unpressurized condition, produces a marked degradation in functional reach capability relative to the nude man condition. For operational visual field, the following conclusions were warranted: (1) The A7L suit provides the superior visual field capabilities for both vision conditions and at all three pressure levels. (2) Specific patterns exist for each pressure suit regarding the effects of pressure on visual field and the degree of visual field capability at specific locations within the field. For all suits, functional relationships, empirically derived, exist for both functional reach and operational visual field. These relationships describe the effects of pressure on these capabilities for each suit and are seen to be linear.

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Keywords

Space suits, Visual fields

Citation