$300 - NASA

1. Report No. NASA CR-1892

4. Title and Subtitle

Development

of a Space Activity

2. Government Accession No. Suit

7. Author(s) James F. Annis and Paul Webb

9. _rforming Organization Nameand Addre_

Webb Associates, Yellow Springs,

Inc. Ohio

45387

12. Sponsoring Agency Name and Address

National Aeronautics

and Space Administration

Washington,

D.C.

15. Supplementary Notes

20546

3. Recipient's Catalog No.

5. Report Date

November 1971

6. Performing Organization Code

8. Performing Organization Report No.

10. Work Unit No.

'11. Contract or Grant No. NASI-8018

13. Type of Report and Period Covered Contractor Report

14. Sponsoring Agency Code

16. Abstra_ Fnis report describes

_he SAS is a new type

the development

of a series of prototype Space Activity

of pressure suit designed especially

for extravehicular

Suit (SAS) assemblies.

activity.

It consists of

a set of carefully tailored elastic fabric garments which have been engineered to supply sufficient

counterpressure

to the body to permit subjects to breathe 02 at pressures up to 200 Tmm Hgwithout

cir-

culatory difficulty.

A closed, positive pressure breathing system (PPBS) and a full bubble helment wet

also developed to complete the system.

The ultimate goal of the SAS is to improve the range of activ-

ity and decrease the energy cost of work associated

with wearing conventional

gas filled pressure suits

_esults are presented from both laboratory

(i atmosphere)

and altitude chamber tests with subjects

wearing various SAS assemblies.

In laboratory tests lasting up to three hours, the SAS was worn while

subjects breathed 02 at pressures up to 170 mmHg without developing physiological

problems.

The only

physiological

symptoms apparent were a moderate tachycardia

related to breathing pressures above

130 mmHg, and a small collection of edema fluid in the hands. Both problems were considered to be

celated to areas of under-pressurization

by the garments.

These problems, it is suggested, can ulti-

mately be corrected by the development

of new elastic fabrics and tailoring techniques.

Energy cost

of activity, and mobility and dexterity of subjects in the SAS, were found to be superior to those in

comparable tests on subjects in full pressure suits.

_ubjects were exposed successfully

to pressures of 20 mm Hg in an altitude chamber.

The exposures were

9f relatively short duration; however, there was no evidence of physiological

or physical damage.

During the hypobaric tests, physiologically

regulated cooling resulted from the free evaporation

of

sweat through the mesh of the garments.

Et the present stage in the development

of the SAS, the authors feel, its problems are primarily mechaz

ical in nature.

Improvements

are needed in methods for donning and closing the garments.

Through the

ase of special fabrics combined with the application

obbiomechanical

analyses of joint function, it is

_lt that mobility can be further improved and the energy cost of activity further lowered.

17. Key'Words(Suggested by Author(s))

Space suit Pressure suit Elastic fabric

eounterpressure

Extra vehicular activity

18. Distribution Statement

19. S_urity _a=if.(ofthisreport) Unclassified

20. Security Classif.(ofthispage) Unclassified

21. No. of Pages

138

*For sale by the National Technical Information Service, Springfield, Virginia 22151

22. Price*

$3 00

TABLE OF CONTENTS

SUMMARY INTRODUCTION

AND HISTORICAL

BACKGROUND

PHYSIOLOGICAL

CONSIDERATIONS

The Skin and the SAS

Gaseous

diffusion

through skin

Diffusion of water through skin

The Body Systems and the SAS

Respiration

and circulatory

balance

pressure

breathing

Thermoregulation

THE SAS SYSTEM

Garments

with positive

Desigri Fabrics Garment

principles

and

and assembly

assemblies

garment materials

engineering

SAS #10--the

Positive

Pressure

Helmet Assemblies

second test phase assembly

Breathing

System

The original Final helmet METHODS

and modified assembly

helmet assembly

Test Program

and Measurements

Physiological Performance

tests and measurements tests and measurements

Suit counterpressure

Equipment

and Techniques

measurement

Instrumentation Instrumentation

used for physiological used for performance

measurements tests and measurements

Subjects RESULTS

Physiological

Results

Cardiovascular

of the Laboratory

Tests

Respiration

Thermoregulation

Performance Energy

Testing in the Laboratory cost of activity

Mobility and dexterity

Altitude Chamber

Tests

DISCUSSION

APPENDIX

A--Suit Specifications

APPENDIX

B--Safety

REFERENCES

Protocol

and Test Plan

iii

page

1 2 8 8

9 9 i0

i0 12 12 12 12 16 21

29 35 44 45 51 56 56 58 59

60 60 61 65 65 67

69 69 74 75 78 78 80 84 93 96 127 131

LIST OF FIGURES

figure 1

9 i0 ii 12 13 14 15 16 17

18 19

20 21 22 23 24 25 26

27 28 29 30 31

Diagram

used in determination

of the tension forces in a

cylinder wall

Typical fabrics

stress-strain

or power

used in SAS construction

curves

for the two elastic

Arrangement Arrangement

of the elements of the elements

in the bobbinet in the powernet

fabric fabric

Photograph Photograph

of a subject of a subject

wearing showing

the slip layer position of the torso

pressur-

izing breathing

bladder (Ist phase) over the slip layer

Photograph

of a subject wearing a-partial

garment of bobbinet

Photograph

of a subject

down attachments

wearing

power layer with helmet hold-

Photograph

of a subject wearing full layer of bobbinet fabric

Photograph Photograph

of fully suited subject of gloved hands

(Ist phase)

Photograph Photograph

of the different

glove types and rounding pads

of the powernet

foot covers (booties)

Photograph

showing the 2nd test phase torso pressurizing

breathing Photograph

bladder, in position over the slip layer of a subject wearing the main helmet

and bladder

restraint

layer of the SAS #i0 assembly

Photograph

of a subject

of the SAS #i0 assembly

wearing

the secondary

restraint

layer

A close-up a subject Photograph

view of the adjustable

counterpressure

girdle on

of a subject wearing the second powernet

girdle

Photograph

of a subject

for the girdles (subject

wearing the SAS #i0 assembly shown walking on a treadmill)

except

Photograph

of the positive pressure

breathing

system (PPBS)

Close-up

view of the exposed components

of the PPBS

Component Photograph

diagram

of the PPBS

of the internal

components

of the PPBS

Diagram

of the liquid

Liquid oxygen transfer

oxygen transfer

system

system in use

Diagram metering

showing device

the basic components

of the digital oxygen

Top and side view of the PPBS regulator Top view of the PPBS motor-blower

assembly

Photograph

of the original

helmet assembly

Line drawing of the original helmet assembly

Some components during construction

of the original

helmet as they appeared

page

14

17 18 19 25

25 26

26 27 27 28 28 28

30

31

32

33 33

34 35 35 37 38 39 40

41 42 43 45 46

48

iv

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