The launch and entry suit (LES) is a life support suit worn during Orbiter ascent and descent. The impact of suit weight and restricted mobility on egress from the Orbiter during an emergency is unknown. An alternate suit - the advanced crew escape suite (ACES) - is being evaluated. The physiological responses to ambulatory exercise of six subjects wearing the LES and ACES were measured and compared to those measurements taken while unsuited. Dependent variables included heart rate and metabolic response to treadmill walking at 5.6 km/h (3.5 mph), and also bilateral concentric muscle strength about the knee, shoulder, and elbow. No significant (p greater than 0.06) differences in heart rate or metabolic variables were measured in either suit while walking at 5.6 km/h. Significant (p less than 0.05) decreases in all metabolic variables were remarked when both suits were compared to the unsuited condition. There were no significant (p greater than 0.05) differences among the three suit conditions at 30 or 180 deg/s for muscles about the elbow and knee; however, about the shoulder, a significant (p = 0.0215) difference between the ACES and the unsuited condition was noted. Therefore, wearing a life support suit while performing Orbiter egress imposes a significant metabolic demand on crewmembers. Selective upper body strength movements may be compromised

Barrows, Linda H.

Greenisen, Michael C.

Hayes, Judith C.

Mcbrine, John J.

Stricklin, Marcella D.

English

NASA Technical Reports Server

NASA
Technical
..... Mar-ch i993
L
RIASA
Physiological Responses to
. " _ ,2.
Wearing the Space Shuttle
Launch andEntry Suit and / .... : :
the Prototype Advanced
Crew ESc_ Suit Compared
to the Unsuited Condition -_ _
~
-=. ;. __. _
Linda H. Barrows, - - - ....
John J. McBrine, - - ....... -
Judith C: Hayes, " .....
Marcella D. Stricklin_ - - : _
an(] Michael C. Greenisen
(NASA-TP-3297) PHYSIOLOGICAL
RESPONSES TO WEARING THE SPACE
SHUTTLE LAUNCH AND ENTRY SUIT AND
THE PROTOTYPE ADVANCED CREW ESCAPE
_i SUIT COMPARED TO THE UNSUITED
)I CONDITION (NASA) 13 p
"I
N93-20319
Unc 1 as
HI/S4 0150340
- /
https://ntrs.nasa.gov/search.jsp?R=19930011130 2020-03-17T07:56:18+00:00Z
k_
w T
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I I
m
NASA
Technical
Paper
3297
1993
National Aeronautics and
Space Administration
Office of Management
Scientific and Technical
Information Program
Physiological Responses to
Wearing the Space Shuttle
Launch and Entry Suit and
the Prototype Advanced
Crew Escape Suit Compared
to the Unsuited Condition
Linda H. Barrows,
John J. McBrine,
Judith C. Hayes,
and Marcella D. Stricklin
KRUG Life Sciences
Houston, Texas
Michael C. Greenisen
Lyndon B. Johnson Space Center
Houston, Texas
E|
m
R
i
CONTENTS
Page
INTRODUCTION ................................................................... 1
METHODS ......................................................................... 2
RESULTS .......................................................................... 2
Five-Minute Walk (n = 6) ............................................................ 2
Strength Testing (n = 6) ............................................................. 3
Maximum TreadmiIl Results (n = 3) .................................................. 7
CONCLUSION ..................................................................... 7
REFERENCES ..................................................................... 8
ACKNOWLEDGEMENTS ........................................................... 8
o..
Ill
PRONG P/_GE BLANK NOT FILMED
45
TABLES
Physiological characteristics (mean _+ SD) of subjects tested in the LES,
ACES, and unsuited ......................................................
V'02 and HR responses (mean -+ SD) to the LES, ACES, and unsuited
conditions at 5.6 km/h (3.5 mph) ............................................
Ve and Vt responses (mean +- SD) to the LES, ACES, and unsuited
conditions at 5.6 km/h (3.5 mph) ............................................
Maximum treadmill responses (mean _ SD) ....................................
Percentage of maximal exercise responses (__+SD) while walking at
5.6 km/h (3.5 rnph) in the LES anc ACES while unsuited ......................
Page
1
2
3
4
5
6
7
FIGURES
Launch and entry suit (LES) .................................................
Shoulder extension ...........................................................
Shoulder flexion .............................................................
Knee extension ..............................................................
Knee flexion .................................................................
Elbow extension .............................................................
Elbow flexion ................................................................
1
4
4
5
5
6
6
iv
INTRODUCTION
The NASA launch and entry suit (LES) is a
llfe support suit currently worn by crewmem-
bers during ascent and descent of the Orbiter.
The LES weighs approximately 35.5 kg (78 lbs).
The impact of suit weight on a crewmember's
agility and physical performance during an
emergency egress from the Orbiter is unknown.
The effect of this additional weight may be mag-
nii]ed upon return from prolonged exposure to
microgravity, as decrements in orthostatic toler-
ance, aerobic capacity, and muscle strength have
been observed immediately postlanding [1].
In an effort to identify physiological respon-
ses while wearing the LES, a study was conduc-
ted by the Exercise Physiology Laboratory (EPL)
and the Anthropometry and Biomechanics Lab-
oratory (ABL) at the NASA]Johnson Space Cen-
ter to evaluate exercise responses while wearing
the LES. The LES is a partial-pressure, dual-
bladder suit and features a built-in g-suit, gloves
that are pressurized on the dorsal surface only,
and a helmet that has a double neck dam (Fig.
1).
A second suit, the NASA prototype advanced
crew escape suit (ACES), was also tested in this
study. The prototype ACES, which is a full pres-
sure suit of approximately the same weight as
the LES, has features that make it similar to
the NASA extravehicular activity (EVA) suit
used when exposed to the vacuum of space. The
ACES also contains a detachable g-suit and has
more extensive ventilation. The ACES helmet
has a single neck dam. The ACES is currently
being evaluated by NASA and may be worn in
place of the LES in future missions.
The purpose of this study was to measure
isokinetic muscle strength and metabolic re-
sponses to ambulatory exercise while wearing
1
}-
- Hclm_
Ilevk_
Pr_w_
Glov_
Helmet 3.4 kg
Suit 6.6 kg
Long Underwear 0.6 kg
Socks 0.1 kg
Boots 2.2 kg
Gloves 0.3 kg
Survival Kit 1.8 kg
Parachute Harness 8.4 kg
LES SUB-TOTAL 23.4 kg
Parachute Pack 11.9 kg*
TOTAL 35.3 kg
Hight Pkg (slide) 20.5 kg
*Note: Parachute Pack used daring Bail Out only.
_'Io.I. Launch and entry suit (LES)
the LES and ACES. These responses were then
compared to similar measurements taken while
unsuited.
METHODS
Six subjects (five males, one female) partici-
pated in this study (Table i). The order of the
tWO-Suited exercise sessionswas randomized and
was performed on consecutive days; the unsuited
test (shorts, T-shirt) was performed 1 to 2 weeks
later. Suited testing incorporated all components
worn during Orbiter ascent and descent, includ-
ing thermal underwear and socks, g-suit, life
support suit, helmet, boots, gloves, and a para-
chute harness weighing approximately 23.5 kg
(52 lbs). The visor of the helmet was left open
for all testing, and subjects were not allowed to
cool themselves through the air ventilation port
of the suii:during testing. Approximately 10
minutes after donning the suit, subjects perform-
ed 3-maximal, isokinetic-concentric repetitions
at 30 and 180 deg/s about the knee, shoulder, and
elbow joints on the right side (LIDO Multi-Joint
Isokinetic Dynamometer, Loredan Biomedical,
Sacramento, CA}. Each joint was tested with
the subject in the supine position. The entire
test sequence was then repeated on the subject's
left sidel Subjects rested for a 5-minute period
after the strength testing was completed and
prior to the treadmill walking. Each subject
then walked on a motorized treadmill (Quinton
Q65, Quinton Instruments, Seattle, WA) at 5.6
km/h (3.5 mph) for 5 minutes. Heart rate (3-lead
Quinton Q5000) and metabolic responses
(Quinton QPLEX) were recorded every 30 secs
during each exercise session. Heart rate (HR)
was obtained from the ECG tachometer and
verified through hand calculation. Metabolic
responses measured included relative oxygen
consumption (VO2), minute ventilation (Ve), and
tidal volume (Vt). Three of the six subjects
volunteered to perform a maximal graded exer-
cisetest [2] as part of their unsuited test session.
RESULTS
Five-Minute Walk (n = 6)
Metabolic data (_ro2, HR, _zt, Ve) were
averaged over the entire 5-minute period. A
multivariate repeated measures ANOVA was
performed, and significant (p < 0.05) differ-
encesam0ng suited C0ndltlons were found for
each metabolic variable. Paired t-tests were us-
ed to identify significant differences among the
three conditions (Tables 2 and 3). No significant
(p = 0.6232 and p = 0.5471, respectively)
difference was found between VO2 and HR while
exercising in the LES and ACES. There also
was no significant (p = 0.9506 and p = 0.4772,
respectively) difference between m_nute ventila-
tion (Ve, BTPS) and tidal volume (Vt) while
walking at 5.6 km/h (3.5 mph) in the LES and
ACES. Significant (p < 0.05) differences, how-
ever, were noted in HR, _'O2, Ve, and Vt when
the LES and ACES were compared to the unsuit-
ed condition.
TABLE 1. Physiological characteristics (mean _ SD) of subjects tested
in the LES, ACES, and unsuited
n=6 n=3*
Age (yr) 34 ___2 36 ± 1
Height (cm) 176.1 _+ 5.5 176.1 ___3.9
Weight (kg) 70.7 __+4.6 72.4 ___3.9
*Maximal treadmill testing
2
TABLE 2. V02 and HR responses (mean _ SD) to the LES, ACES, and
unsuited conditions at 5.6 km/h (3.5 mph)
_/02 (mL • kg- 1 • min- 1)
Mean _+ SD p* Mean
HR (bpm)
± SD p*
LES 24.4 1.9 0.0001 140 16 0.0001
ACES 24.2 2.3 0.0001 137 13 0.0001
Unsuited 15.7 1.2 --- 105 11 ---
*Compared to unsuited condition
TABLE 3. Ve and _rt responses (mean _ SD) to the LES, ACES, and
unsuited conditions at 5.6 km/h (3.5 mph)
_e (L/min)
Mean ± SD p* Mean
"v't(liters)
± SD p*
LES 43.8 11.1 0.0058 1.9 0.6 0.0176
ACES 43.6 9.3 0.0028 1.8 0.3 0.0006
Unsuited 24.7 5.6 --- 1.3 0.3 ---
*Compared to unsuited condition
Strength Testing (n = 6)
A multivariate repeated measures analysis
of variance was used to determine significant
differences in isokinetic muscle strength be-
tween the two suits and the unsuited condition.
No significant (p > 0.05) differences occurred
among the three conditions at either 30 or 180
deg/s for muscles about the elbow and knee
joints. There was a significant (p = 0.0164) dif-
ference among the three suited conditions for
shoulder extension at 30 deg/s. A post-hoc
dependent t-test indicated a significant (p =
0.0215) difference between the new ACES ver-
sus the unsuited condition on the right shoulder
extension. While no significant differences
between the two suits were apparent, this sig-
nificance was not demonstrated at 180 deg/s.
Mean torque values and standard errors for each
muscle group are presented in Figs. 2 through 7.
I00-
90=
80-
,--, 70-
6o-
50-
40-
30.
20-
I0-
Left
[*Z
;g .....
l
Ri :ht
30 deg/s
*p < 0.05
_G. 2. Shoulder extension
I00-
90-
80-
_, 7o-
_ 50-
_ 4o-
30-
20-
10-
0
L_
T
tt _i_i_i_i_i_i_iii_i_i
_iiiiiiiiiiii
ift Ri ':ht
30 deg/s
_c,. 3_ Shouider flexion
I_ft
[] LES
[] ACES
[] Unsuited
[] LES
[] ACES
Unsuited
!
Right
180 deg/s
250
225
20O
=1 150
[_ 125-
[] LES
[] ACES
[] Unsuited
50
Left Right
30 deg/s
FIG. 4. Knee extension
Left Right
180 deg/s
Left
FIG. 5. Knee flexion
Ri ;ht
30 deg/s
[] LES
[] ACES
[] Unsuited
Right
180 deg/s
5
100-
90-
80-
50-
40.
"_ 30-
20,
10.
0 ?
Left Right
30 deg/s
FIG.6. Elbow extension
I00-
90-
80-
70-
_I 50-
g
20.
10-
0
IT
!
Left Right
30 deg/s
FIG. 7. Elbow flexion
i
[] LES
[] ACES
[] Unsuited
Left Right
180 deg/s
[] LES
[] ACES
[] Unsuited
.... : .... v ::=_
Left Right
180 deg/s
Maximum Treadmill Results (n = 3)
The treadmill responses of the subjects who
volunteered to perform a maximal test as part of
their unsuited session are shown in Table 4.
The percentage of maximal exercise at which
subjects were working while walking at 5.6 km/h
(3.5 mph) in the LES, in the ACES, and while
unsuited is presented in Table 5.
CONCLUSION
Similar metabolic responses to ambulatory
exercise were obtained for the LES and ACES.
However, metabolic responses were significantly
higher during ambulation while wearing either
suit when compared to the unsuited condition.
A 15-20% increase was noted in the maximal
exercise response seen for all metabolic variables
when walking at 5.6 km/h (3.5 mph) in the suit-
ed condition.
No apparent impact was observed on con-
centric muscle strength about the knee and
elbow joints at the angular velocities tested
while wearing a suit. Shoulder strength during
extension, however, appears to be compromised
at a velocity of 30 deg/s but not at the higher
velocity of 180 deg/s. This seems to be due to
higher torque values in the unsuited condition.
Therefore, wearing a suit while performing
egress from the Orbiter would impose a signif-
icant metabolic demand on the crewmember, and
selective upper body strength movements may
be compromised while wearing either the LES or
ACES.
TABLE 4. Maximal treadmill responses (mean _-¢-SD)
Variable Mean + SD
VO2 (mL. kg- ! • min- 1) 61.1 12.3
HR (bpm) 202 4
Ve (L/min) 161.4 28.9
Vt (L) 3.0 0.3
TABLE 5. Percentage of maximal exercise responses (--+SD) while walking at
5.6 km/h (3.5 mph) in the LES and ACES and while unsuited
Variable LES ACES Unsuited
%VO2(mL'kg -I "min-D 41.6 _ 10.1 42.4 _ 10.1 26.5 + 4.5
%HR(bpm) 67.1 ± 10.1 66.0 - 4.3 50.8 + 5.8
%Ve (L/min) 26.9 _ 12.5 28.2 + 9.0 16.3 _ 4.2
%_rt(L ) 69.9 + 17.8 64.1 _ 0.7 44.6 _ 4.1
7
The findings of this study are somewhat
limitedl First, only six subjects were tested.
Second, it should be noted that the subjects wore
the same suit size (a criteria for subject selec-
tion). Crewmembers at the extreme limits for
height and weight, per astronaut corps specifica-
tions, were not represented. Third, the impact of
thermal load on exercise responses and the time
course of thermal demands on body were not
investigated. A better understanding of the
physiological demands of wearing a suit during
exercise will be obtained with further testing.
REFERENCES
[1] NICOGOSSIAN, A.E. Overall Physiological
Response to Space Flight. In: Space-Phys-
iology and Medicine, 2nd Ed (A. E.
Nicogossian, C L. Huntoon, and S. L. Pool,
eds.). Philadelphia, PA: Lea & Febiger,
1989.
[2] CUNNINGHAM, L. N. Physiologic character-
istics and team performance of female high
school runners. Pediatric Exercise Science,
1:73-79, 1989.
ACKNOWLE DGEMENTS
The authors wish to thank the following
individuals at the NASA/Johnson Space Center
for their contributions to the investigation:
• Glenn K. Klute, Anthropometry and Bio-
mechanics Laboratory
• Nancy J. Sherlock and James P. Bagian,
Astronaut Corps
• Members of the Crew & Thermal Systems
Division

.[
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4. 5 FUNDING NUMBERS
6.
TITLEAND SUBTITLE
Physiological Responses to Wearing the Space Shuttle Launch and Entry Suit
and the Prototype Advanced Crew Escape Suit Compared to the
Unsuited Condition
AUTHOR(S)
Linda H. Barrows. John J. McBrine. Judith C. Hayes. Marcella D. Stricklin.
and Michael C. Greenisen
7. PERFORMING ORGANIZATION NAME(S) AND ADDRES'S(ES)
Medical Sciences Division
Space Biomedical Research Institute
National Aeronautics and Space Administration
Lyndon B. Johnson Space Center
Houston, TX 77058
SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)
National Aeronautics and Space Administration
Washington. DC 20546-0001
PERFORMINGORGANIZATION
REPORTNUMBER
S-694
10 SPONSORING /MONITORING
AGENCY REPORT NUMRFR
NASA TP-3297
11. SUPPLEMENTARY NOTES
Barrows. McBrine. Hayes. and Stricklin: KRUG Life Sciences. Houston. TX:
Greenisen: Lyndon B. Johnson Space Center. Houston. TX.
12a DISTRIBUTION/ AVAILABILITYSTATEMENT
Unclassified-Unlimited
Subject Category 54
12b. DISTRIBUTIONCODE
13. ABSTRACT(Maximum 200 words)
The launch and entry suit (LES) is a life support suit worn during Orbiter ascent and descent. The impact of suit
weight and restricted mobility on egress from the Orbiter during an emergency is unknown. An alternate suit - the
advanced crew escape suit (ACES) - is being evaluated. The physiological responses to ambulatory exercise of six
subjects wearing the LES and ACES were measured and compared to those measurements taken while unsuited.
Dependent variables included heart rate and metabolic response to treadmill walking at 5.6 km/h (3.5 mph), and
also bilateral concentric muscle strength about the knee, shoulder, and elbow. No significant (p > 0.05) differences
in heart rate or metabolic variables were measured in either suit while walking at 5.6 km/h. Significant (p < 0.05)
decreases in all metabolic variables were remarked when both suits were compared to the unsuited condition. There
were no significant (p > 0.05) differences among the three suit conditions at 30 or 180 deg/s for muscles about the
elbow and knee; however, about the shoulder, a significant (p = 0.0215) difference between the ACES and the
unsuited condition was noted. Therefore, wearing a life support suit while performing Orbiter egress imposes a
significant metabolic demand on crewmembers. Selective upper body strength movements may be compromised.
14.
17_
SUBJECTTERMS
suits, launch and entry (LES); suits, advanced crew escape (ACES); suits, life support;
responses, physiological; metabolism
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Physiological responses to wearing the space shuttle launch and entry suit and the prototype advanced crew escape suit compared to the unsuited condition

Physiological responses to wearing the space shuttle launch and entry suit and the prototype advanced crew escape suit compared to the unsuited condition

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