Development of large area micrometeoroid impact detector panel

Cook, W. M., Jr.

Mayo, J. W.

English

NASA Technical Reports Server

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U. S. Patent No. 
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NOTE - If t h i s  patent covers an invention made by a coqorate 
of a NASA Contractor, the following is a2pbicable: 
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https://ntrs.nasa.gov/search.jsp?R=19710006746 2020-03-17T02:36:40+00:00Z
J. W. M A Y 0  E T A L  
DETECTOR PANELS-MIGROhlETEOROID IMPACT 
2 Sheets-Sheet 1 
Y 
e 
s 
DETECTOR PANELS-MICROMETEOROID IMPACT 
2 Sheets-Sheet 2 
61' 
52 
e 
INVENTORS 
U.S. a. 93-433 10 Claims 
A large area meteoroid det&cE?r panel fabricated &Om 
two sheets of metal attached together to form a presure 
vessel which contain a plurality of celk and m e  or more 
sensing devices. Meteoroids penetrating one of the shuts 
cause a loss of pressure withim the panel which loss is 
detected by one of the sensing devices. 
ORIGIN OF INVENTION 
The invention described herein was made by employees 
of the United States Government and may be manufac- 
tured and used by or for the Government for govern- 
mental purposes without the payment of any royalties 
thereon or therefor. 
Micrometeoroid impact detector devices in use prior 
to the present invention consisted of pressurized cells 
small cadmium sulfide cell detectors, steel covered wire 
grids, copper wire-wound cards, and capacitance type de- 
tectors. The pressurized cells previously used comprised 
a can type detector having a small exposed area (approx. 
1 sq. ft.) which were made to detect micrometeoroid 
penetration of its thin skins (approx. .005” and under). 
Their use with larger areas and thicker skinned ma- 
terials is therefore not practical. The exposed detector 
weight-to-area ratio was disadvantageous in many cases 
since only one side of the detector was exposed to the 
micrometeoroid hazard. Most of these detectors were 
unusable at high temperatures due to melting or decom- 
position of the component parts. Furthermore, the previ- 
ous structures were more complicated than the present 
invention, and this increased the potential for malfunc- 
tions. 
The present invention provides a micrometeoroid de- 
tector having relatively large areas (several square feet 
and larger), an improved weight-to-area ratio for any 
given thickness and material, an extremely simple de- 
sign entailing a minimum number of parts which en- 
hances its reliability and facilitates ease of production. 
It is therefore an object of the present invention to pro- 
vide a micrometeoroid detection device that can be fabri- 
cated from a variety of spacecraft materials and skin 
thicknesses, and in an unlimited variety of sizes, shapes 
and curvatures. 
Another object of the present invention is to provide a 
detection device that can be simply constructed, light- 
weight, need little or no support structure, and require 
a minimum of mounting hardware. 
Still another object of the present invention is to pro- 
vide a qevice which can have both sides exposed to the 
micrometeoroid environment so as to provide a better 
area-to-weight ratio. 
A still further object of the present invention is to pro- 
vide a detector device having the ability to withstand a 
wide range of temperatures, and be insensitive to space 
radiation. 
These and other objects of the present invention will 
become more apparent from a reading of the following 
description. 
In the drawing: 
FIG. 1 shows an isometric view of the invention panel 
and the manner of attaching the metallic sheets so as to 
form a panel; 
FIG. 2 is a cross sectional View taken along the sec- 
tion line 2-2 of FIG. I; 
FIG. 3 is a cross sectional view taken along fine 3-3 
of FIG. 1; 
FIG. 4 is a cross sectional view of another embodi- 
Lo ment of the present invention; 
FTG. 5 is a top view of another embodiment of the 
present invention showing a panel stiffener arrangement; 
FIG. 6 is a cross sectional view of the stieener em- 
bodiment taken along line 5-5 of FIG. 5;  and 
FIG. 7 is a top view of another embodiment of the 
present invention having a waffle celled co-uration. 
Referring now to FIG. 1, wherein the numeral 10 
designates generally the invention, there is shown a sec- 
tion of the detector panel 10 formed by placing together 
20 two sheets of test material 12 and 14, welding or joining 
in some other manner, such as bonding, diffusion bond- 
ing, brazing, these sheets about the panel periphery 18 
and cell periphery 20 so as to form cells 16. This method 
may be utilized to form the waffle configuration of FIG. 
25 7 and the stiffener reinforced conguration of FIG. 5 by 
forming the sheets 12 and 14 in a suitable configuration. 
The cell periphery welds 20 are internipted at one 
place where pressure connector tubes 22 are formed. 
These tubes serve to provide a panel which has intercon- 
30 nected cells. In this way, only one pressure sensor is 
needed to detect the penetration of any part of the ex- 
posed area of each panel. The location of these pressure 
sensors 24 on each panel is indicated in FIG. 3. This fig- 
ure shows a side view of the panel taken along a cell De- 
35 riphery weld. A pressure sensor 24 of the type disclosed 
in Pat. 3,238,744 is shown attached to a flattened part of 
the cell wall. These sensors may be located on any one 
cell or group of interconnected cells in the panel and 
preferably closest to the data recording mechanism of the 
4o satellite so as to keep connector wiring to a minimurn. 
The cross sectional view of FIG. 3 gives a clearer indi- 
cation of the location of the pressure sensor 24. 
An alternate embodiment of the present invention des- 
ignated generally by the reference numeral 30 has *’ flattened detector cells as shown in a cross sectional view 
in FIG. 4. In this embodiment there is an upper sheet 
32 and a lower sheet 34. They are joined at the periphery 
with a weld 40. Weld 42 also joins the sheets along the 
tubular portions 36 and 38. 
Another arrangement of the invention is shown in 
FIGS. 5 and 6 and designated generally by the reference 
numeral 50. This embodiment may have a preformed 
upper sheet 52 and lower sheet 54 joined by a periphery 
55 weld 60. The cell portions of the upper sheet are alter- 
nately tubular an8 flat as are the cells of the bottom 
sheet; however, the sheets are joined SO that the cells are 
formed of tubular portions 56 that oppose the flat por- 
tions 58. The sheets are joined between the cells by weld 
Bo 62. Stiffeners 59 may be preformed in the alternate flat 
cell portions so that one side of the cell will have the 
tubular configuration while the other side has a stiffener 
configuration. These stiffeners are tubular projections 
formed in the flattened portion of the cell wall. The cen- 
65 tral stiffener tube 61 (FIG. 5) extends from one cell to 
the next across the panel and acts as a pressure conduit 
for interconnecting the cells. 
The panels and cells can be made in any shape, size or 
curvature. This is illustrated by the waffle configuration 
70 of the panel and its cells shown in FIG. 7 and designated 
generally by the reference numeral 70. This panel, like 
the others has an upper sheet 72 and lower sheet 74 weld4 
15 
6o 
3,526,139 
3 4 
at SO around its periphery. The cell codguration is ob- 
tained by seam welds 82 which leave spaces $4 for pres- 
surized communication between the cells. 
In operation the panels in all of the embodiments are 
provided with a pressure sensitive switch and the panels 
pressurized by known techniques. The panels are incorpo- 
rated into a space vehicle of chosen design and are posi- 
tioned so that both sides of the cells are exposed to mete- 
oroid penetration in the space environment. When a cell 
is penetrated a pressure loss occurs which is detected and 1o have alternau and opposed tubular and ffat portions. 
recorded by conventional mechanism. 
Letters Patent of the United States is: 
comprising: 
3. The apparatus as in claim 1 wherein both sides of 
the detector panel means are exposed to the micromete- 
oroid environment. 
4. The apparatus as in claim 1 having an exposed sur- 
face area approaching that of the projected flat plate 
area. 
5. The apparatus as in claim wherein the panel cells 
are tubular. 
6. The apparatus as in claim 1 wherein the panel cells 
7. The apparatus as .in claim &Wherein the flat portions 
What is claimed as new and desired to be secured by 
8. The apparatus as in claim 1 wherein the sheets and 
1. A micrometeoroid penetration detecting apparatus 
9. The apparatus as in claim 1 wherein the panel cells 
self-supporting pressurized detector panel means, said l5 have alternate and opposed tubular and flat cell portions; 
panel means consisting of two thin sheets of metal said flat cell portions having stiffeners; 
joined together, said sheets being joined in such a said stiffeners being protrusions located at spaced in- 
manner that they form a plurality of cells to make tervals and generally transverse to the tubular and flat 
up an integrated self-supporting unit; said cells hav- 20 Cell Portions. 
ing an internal volume substantially greater than that 10. A micrometeoroid detecting apparatus as in claim 
of the sheets thereby providing a lightweight strut- 1 wherein said cells are individual pressurized compart- 
ments, and pressure sensor means for each cell. ture; and 
pressure sensors means associated with said cells for References Cited detecting pressure drop due to meteoroid penetra- 25 
lion of cell walls. UNITED STATES PATENTS 
have stiffeners formed therein. : 
cell areas are joined by welding. 
2. A micrometeoroid detecting apparatus as in claim 1 657,672 9/1911 Petternell _ _ _ _ _ _ _ _ _  1 0 9 4 2  X 
wherein said cells have passages therebetween, said pres- 3,238,774 3/1966 Gurtler _ _  _ _ _ _  73-170 
sure sensor means detecting pressure drop due to micro- 
meteoroid penetration of any panel cell wall. 30 s. CLEMENT SWISHER, Primary Examiner 


Detector panels-micrometeoroid impact Patent

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