Long term vacuum storage test and vibration effects analysis of multilayer super insulation blanket

Carr, R. W.

Lankton, C. S.

English

NASA Technical Reports Server

t tt. fi 
DIN: 67SD4405-S 
1 NOVEMBER 1967 
SUPPLEMENT TO 
VOYAGER THERMAL INSULATION S Y S T E M S  
PHASE II SUMMARY REPORT 
LONG T E R M  VACUUM STORAGE TEST 
A N D  VIBRATION EFFECTS EVALUATION ON 
MULTI-LAYER SUPER INSULATION BLANKETS 
B Y  
R.W. CARR 
C.S. LANKTON 
GPO PRICE $ 
CFSTI PRICE(S) $ 
PREPARED FOR 
Hard copy (HC) 
Microfiche (MF) 
ff 653 J I v 6 5  
J t i  I'ROPULSION LABORATORY 
PASADENA, CALIFORNIA 
UNDER JPL CONTRACT NO. 951537 
G E N E R A L @  E L E C T R I C  
M I S S I L E  A N D  S P A C E  D I V I S I O N  
Valley Forge Space Technology Center 
P.O. Box 8555 Philadelphia 1, Penna. 
https://ntrs.nasa.gov/search.jsp?R=19680005899 2020-03-12T12:04:38+00:00Z
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DIN: 67SD4405-S 
1 NOVEMBER 1967 
SUPPLEMENT TO 
VOYAGER THERMAL INSULATION S Y S T E M S  
PHASE II SUMMARY REPORT 
LONG T E R M  VACUUM STORAGE TEST 
A N D  VIBRATION EFFECTS EVALUATION ON 
MULTI-LAYER SUPER INSULATION BLANKETS 
BY 
R.W. CARR 
C.S. LANKTON 
PREPARED FOR 
JET PROPULSION LABORATORY 
PASADENA, CALIFORNIA 
UNDER JPL C O N T R A C T  NO. 951537 
THIS WORK WAS PERFORMED FOR THE JET PROPULSION LABORA- 
TORY, CALIFORNIA INSTITUTE OF TECHNOLOGY, A S  SPONSORED 
BY THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
UNDER CONTRACT NAS 7-1 00. 
G E N E R A L @  E L E C T R I C  
M I S S I L E  A N D  S P A C E  D I V I S I O N  
Valley Forge Space Technology Cenler 
P.O. Box 8555 Philadelphia 1, Penna. 
t 
This report was prepared by the General Electric Company under Contract No. 951537, 
Planetary Vehicle Thermal Insulation Systems, for the Jet Propulsion Laboratory. It 
is a supplement to the Phase 11 Summary Report, dated 11 September 1967. The work 
was administered under the technical direction of the Advanced Engineering Section, 
Engineering-Mechanics Division of the Jet Propulsion Laboratory, with Mr. Donald Ting 
acting as Technical Director. 
Submitted by: U4*cvcc-  
A. D. Cohen, Program Manager (PVTIS) 
General Electric Company 
Donald Ting, Technical Director 
Jet Propulsion Laboratory 
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ABSTRACT 
Super insulation blankets were subjected to  a sixty day exposure to  vacuum levels in  the 
tor r  range while radiating to  walls cooled by liquid nitrogen. At the end of the sixty 
day time period, the blankets were subjected to  broad-band vibration levels of 3.77 G to 
4.66 G RMS while at vacuum/cryogenic conditions. There was  no apparent physical damage 
to the insulation and no measurable change in the thermal performance. 
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TABLE OF CONTENTS 
Section 
1 
2 
INTRODUCTION . . . , . . . e . . . . . . . . 
TECHNICALDISCUSSION. . . . . . . . e . . . 
2 . 1  Test Fixture Description . e e . . e . . a 
2.2  Test  Blanket Description . . . . . . . . . . 
2 . 3  Test  Facility and Equipment . . . . . . . . . . e 
2.4 Test  Results . . . . . . . . e . . e 
CONCLUSIONS. . . . , . . . . . a . . . . . . . 
RECOMMENDATIONS . . . . . . . . . . . . e 
NEW TECHNOLOGY. . . . . e . e . . . . . . 
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LIST OF ILLUSTRATIONS 
Figure 
1-1 
2-1 
2-2 
2-3 
2 -4 
2-5 
2 -6 
2 -7 
2-8 
2-9 
2-10 
2-11 
2-12 
Page 
Random Vibration Spectrum . . . . . . . . . . . . . . 2 
Long Term Thermal Vacuum Test Fixture . . . . . . . . . 
Dismantled Test Fixture , . . . . . . . . . . . . . . 
Body Insulation Blanket. e . . . . . . . . . . . . e . 
End Insulation Blanket . . . . . . . . . . . . . . . 
Flange Insulation Blanket . . . . . . . . . . . . . . 
Flange Insulation Detail. . . . . . . . . . . . . . 
Corner Insulation Detail . . . . . . . . . . . . . . 
Tinger Fasteners. . . . . , a . . . . . . . . . . 
Assembled Insulated Test Fixture . . . . . . . . . . . 
Exciter Mounting. . . , . . . . . . . . . . . . . 
Power Spectral Density-Control Accelerometer. . . . . . . 
Power Spectral Density-Accelerometer No. 2 . . . e . . . . 
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SECTION 1 
INTRODUCTION 
A s  part of the subject program, it was required to demonstrate that the super insulation 
material, when assembled into blankets, could survive the expected vibration levels caused 
by firing of the orbit insertion motor after several months of exposure to space vacuum and 
temperature conditions. A secondary objective was to measure the thermal performance of 
the insulation material after initial temperature stabilization and again after vibration to 
determine if any significant change in thermal performance occurred. For this test, the 
materials were exposed to vacuum levels in the 10 
below -280 F. A t  the conclusion of the exposure period, and while the specimen was  under 
vacuum/low temperature conditions, it was vibrated at the levels that approximate those 
shown in Figure 1-1 which are  representative of vibration levels expected from a liquid 
rocket engine. 
-a 
t o r r  range and to a sink temperature 
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0.01 I 
0.0001 I I I I I I I l l  I I I I l l l l l  I I I I I I I  
10 loo 1000 
FREQUENCY (Hz) 
Figure 1-1. Random Vibration Spectrum 
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SECTION 2 
TECHNICAL DISCUSSION 
2.1 TEST FIXTURE DESCRIPTION 
The test fixture was  a 14-in. diameter by 14-in. long right circular cylinder a s  shown in 
Figures 2-1 and 2-2. 
2.2 TEST BLANKET DESCRIPTION 
The test blankets a re  as shown in Figures 2-3 through 2-7. The 1/4-mil gold coated Mylar 
and 1/2-mil gold coated Kapton were crinkled by pulling the sheet material through a 
Teflon die. The sheets were perforated prior to crinkling with nine 1/8-in. diameter 
holes per square foot. The uncoated 2 mil Kapton cover sheets were drilled with the same 
hole pattern. Holes to accommodate the Tinger fasteners were 0.30 inches in diameter. 
The Tinger fasteners a r e  described in Figure 2-8. The blankets were  restrained on the 
posts by nylon split-washers snapped into the machined shoulder on top of the Tinger. 
The blankets were taped at the joints with one inch wide, one mil Kapton tape coated with 
pre s sure  sensitive cement, 
The following materials and sources of supply were used. 
1/4-mil, gold coated Mylar 
1/2-mil, gold coated Kapton 
2 mil Kapton cover 
Tinger Fasteners General Electric Company 
Velcro nylon hook and pile tape 
Adhesive backed Kapton Tape 
National Metallizing 
National Metallizing 
DuPont DeNemours, Inc. 
Velcro Corp. 
Technical Fluorocarbons Eng. , Inc. 
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CHAMBER L10 
(REF) 
CHAMBER FIXTURE 
(REF) 
1/16" THIMBLES (3 REQ'D) 
- 3 PLACES 
SPRING NO. LE495J-1 
MTL 
LEE SPRING CO. ( 3 REQ' D) 
MOUNT A S  CLOSE TO CHAMBER 
FIXTURE A S  POSSIBLE 
CONE ASSY 
TEST FIXTURE 
(SEE NOTE) 
1 /16" SS CABLE ( I  X 7) FASTEN 
WITH 1/16" SPLICING 
SLEEVES (4 REQ' D) 
1/16" THIMBLES (2 REQ' D) 
- 6 PLACES 
S P R I N G  LE-0953-1 
LEE SPRING CO. 
MTL-MUSICWIRE-6 PLACES 
INSTALL SPRING TO INTERFACE 
RING AT ONE END 
EXCITER 
CLAMP SEGMENT 
(3 REQ' D) 
NOTE: BUTTONHOLESTOBELOCATED 
I N  TEST FIXTURE FROM BLANKET 
TEMPLATES 
CRIMPED 1 
SPLl CI NG 
SLEEVE 
THIMBLE 
TYPICAL CABLE JOINT 
Figure 2-1. Long Term Thermal Vacuum Test Fixture 
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-- --- TL E ' ,Iz/ E - 6 -  
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A21 
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19 LAYERS 112 MIL GOLD COATED KAPTON 
1 LAYER 2 MIL KAPTON 
1/4 MIL GOLD COATED MYLAR 
MIL KAPTON 
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1. 1 '2 MIL KAPTON AND 
1 14 MIL MYLAR TO BE 
CRINKLED AND PERFORATED 
2. 2 MIL KAPTON TO BE 
PERFORATED 
Figure 2-4. End Insulation Blanket 
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19 LAYERS 1/4 MIL GOLD COATED MYLAR--CRINKLED AND PERFORATED. 
1 LAYER 2 MIL KAPTON--PERFORATED 
Figure 2-5. Flange Insulation Blanket 
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n 
INSULATION ON BODY BLANKET 
SUPPORT CABLE 
I "  WIDE -SPIRAL WRAP 
FOR 4" 
SL IT  AND TAPE FLANGE FIXTURE 
BLANKET AS REQUIRED 
FLANGE BLANKET 
TAPE EVERY 6" 
Figure 2-6. Flange Insulation Detail 
COVER SHEET 
TAPE EVERY 6 IN. , 
COVER SHEET 
END BLANKET 
SL IT  INNER LAYERS AS REQUIRED 
TOROUNDCORNER 
BODY BLANKET 
SLIT OUTER LAYERS AS REQUIRED 
x) ROUND CORNER 
Figure 2-7. Corner Insulation Detail 
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2 . 3  TEST FACIJJTY A N D  EQUIPMENT 
The test was performed in a 2 f t  by 2 ft thermal vacuum chamber located at the Valley Forge 
facility. Photographs of the test fixture and vibration exciter a r e  shown in Figures 2-9 
and 2-10. 
2.4 TEST RESULTS 
2 . 4 . 1  TEST CONDITIONS 
The vacuum level throughout the test was maintained between 1. G x lo'? and 2 . 5  x 
0 
torr. Shroud temperatures were helow -280 F during the test. A reference internal 
temperature of the test model was  held between +36 F and +51°F with variations of +lO°F 
to -9 F from the reference location. 
hours (60 days) before vibration excitation,plus four days for evaluation of thermal 
conductance change. 
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0 The total exposure to the test conditions was 1440 
2 . 4 . 2  VIBRATION TEST 
Prior  t o  starting the vacuum test, the vibration spectrum w a s  run  under ambient pressure 
and temperature conditions to check out operation of the vibration set-up. The vibration 
levels simulated, as  closely as possible, vibration levels measured in static tests of the 
LEMDE thrust chamber assembly. The total vibration time was three and one-half minutes. 
An inspection of the insulation system indicated no visible damage after the excitation 
At the conclusion of the sixty day thermal vacuum exposure, and with vacuum and temperature 
conditions maintained, the model was again subjected to vibration. Figures 2-11 and 2-12 
depict the power spectral density for the control accelerometer and accelerometer No. 2,  
respectively. Two accelerometers were used for redundancy purposes, in case of failure 
of one of the units. The frequency spectrums were essentially unchanged from the values 
recorded prior to the start of the vacuum exposure cycle. A s  may be seen from Figure 2-11, 
the overall vibration spectrum showed reasonable correlation with the specified levels. 
Several peaks at 160, 460, 550, 650, 730, and 840 cycles a r e  considerably above the 
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Figure 2-9. Ass embled Insulated Test Fixture 
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0.0001 I I 1 I I I I I I  I I I I I I d  I I I I I I I I  
100 1000 
FREQUENCY (Hz) 
Figure 2-11. Power Spectral Density-Control Accelerometer 
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0.001 
0.0001 I I I I I I I l l  I I I I I l l !  I I I I I I I  
100 1000 
FREQUENCY (Hz) 
Figure 2-12. Power Spectral Density-Accelerometer No. 2 
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specification levels and peaks at 900, 960, 1700, and 1800 cycles a r e  below specification 
levels. These correspond to resonances in the test fixture, which were  confirmed by a 
plot of acceleration/exciter voltage versus frequency. 
Total vibration time for the vacuum vibration test was five minutes and 18 seconds, with 
120 seconds a t  the specified test levels. 
2.4.3 INSUMTION THERMAL PERFORMANCE 
The long term vacuum test provided an opportunity to obtain data on the effectiveness of the 
multilayer insulation design proposed for the full scale tests. 
insulation on the 14-inch long cylinder should be appreciably worse than that applied to the 
ful l  scale fixtures because of the increased length of joint seams and increased number of 
support posts per unit area on the smaller model. In addition, the support cables and 
electrical lead wi re s  will  cause a greater proportionate thermal leakage in the small model 
than wi l l  similar disturbances in the full scale test. 
The performance of the 
During test with liquid nitrogen-cooled chamber walls, 3.7 watts power was  required to 
maintain the model at  about 40 F. A t  this condition, thermocouples mounted on the cylinder 
ends adjacent to the heaters read about 45 F, and thermocouples near the central parting 
flange were about 35 F. The 3.7 watts power value is an average over one day's time, with 
the actual values up to  0.2 watts above that at night and about the same amount below during 
the day due to plant line voltage fluctuation. 
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The lead w i r e  bundle included six 24-gage copper-constantan thermocouple lead wire pairs , 
six 20-gage copper heater power wires ,  two accelerometer coaxial cables, and the shaker 
power cable. 
included a thermocouple 2.5 inches from the model. The couple read about -65 F during 
test. Calculations show that at  least 0.5 watts could leak through this bundle at  these 
conditions. 
This bundle was  wrapped with insulation to about 5 inches from the model, and 
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The model was supported by three 1/16-in. diameter steel cables. Thimbles were used at 
each eyebolt in the model flange. 
insulation used to cover the flange area of the model. There is no readily available data on 
the thermal loss through this type of insulation penetration, but is estimated that the leak is 
probably as much as  0.7 watts total for the three cables. 
through the insulation is estimated to  be 2.5 watts (3.7 - 0.5 - 0.7) .  
The cables and thimbles penetrated the "belly band" of 
Thus, the heat loss directly 
Including both sides of the one-inch wide central flange, the model has 7.08 square feet of 
surface area. This gives a heat loss of about 0.35  watts per square foot. If the heat loss 
were that much from the 472 square foot full scale capsule fixture, it would result in 165 
watts loss. 
be within the values specified by JPL as  design requirements for the program. 
0 This is higher than the calculated capsule loss of 106 watts at 40 F, but it would 
Data was  taken after completion of the vibration cycle and no measurable change in thermal 
performance was noted. 
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SECTION 3 
CONCLUSIONS 
The results of the vacuum/vibration test have led to  the following conclusions: 
a. The insulation material, Velcro mounting pad material, tingers, and tape exhibited 
no noticeable damage or  change in physical appearance o r  function after exposure 
to  vacuum and vibration. 
b. The insulation system as installed on the fixture exhibited no measurable change in 
thermal performance after exposure to  the vibration. 
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E SECTION 4 
RECOMMENDATIONS 
It is recommended that this test be considered a materials qualification test for the ability 
of the materials listed in Section 2.2 t o  withstand the vacuum and thermal environments 
encountered during the planetary transfer orbit followed by the vibration levels expected from 
the firing of the orbit insertion rocket engine. 
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SECTION 5 
NEW TECHNO LOGY 
N o  reportable items of new technology are deemed to have resulted from the effort reported 
herein. 
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Long term vacuum storage test and vibration effects evaluation on multi-layer super insulation blankets.  Supplement to Voyager thermal insulation systems.  Phase 2 - Summary report

Long term vacuum storage test and vibration effects evaluation on multi-layer super insulation blankets. Supplement to Voyager thermal insulation systems. Phase 2 - Summary report

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