Payload/spent rocket engine case separation syste

Watson, N. D.

English

NASA Technical Reports Server

ATTN 0 6  
FROMt 
N A T I ~ N A ~  AERONAUTICS AND SPACE A 
WASHINOTOW, D.C. 20546 
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A 
In accordance 
and Code U S I ,  
forwarded for 
The following 
w i t h  the procedures agreed upon by C o d e  GI? 
the attached NASA-awned U. $3, Patent is being 
abstracting and announcement in N M A  STAR- 
information i s  'prcovidedr 
U. S. Patent No. .' ,. I 
Government or 
Corporate Employee t 
Supplementary Corporate 
Source (if applicable) t 
NASA Patent Case No. 
NOTE - If t h i s  patent covers an invention made by a corporate 
employee 
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inventor (author 
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ation, folbawiaag WQZdS m e  ., e W& 
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https://ntrs.nasa.gov/search.jsp?R=19710006212 2020-03-17T02:41:49+00:00Z


Appl. No. 765,123 
Filed Oct. 4,1968 
Assignee 
the United States of America as represented 
by (the A ~ ~ j ~ ~ ~ a ~ o r  of the National 
A e r o ~ a M ~ ~ ~  and Space ~ d m ~ ~ i s ~ ~ t j o ~  
References Cited 
UNITED STATES PATENTS 
3,384,016 5/1968 Blanchard .................... 102/49.5 
3,431,854 3/1969 Rabenhorst .................. 107149.4 
Primary Examiner-Verlin R. Pendegrass 
Arlorneys-Howard J. Osborn and G. T. McCoy 
[561 
3,185,096 5/1965 Daudelin ...................... 102149.4 
Field of Search ............................................ 102149.4, 
49.5; 244/1(S.S.) 
ACT: A payload separation system wherein a Marmon 
Band clamp separates a spent motor case from the payload. A 
retrorocket fixed to the motor case is fired to cant the motor 
case. Another opposed retrorocket is ignited while the first 
one is still burning and together they move the spent motor 
case out of the path of the payload. 
3,534,686 
1 2 
~ , ~ ~ ~ ~ A ~ / ~ ~ ~ ~ E ~ - ~ ~ ~  MOTOR CASE § ~ ~ A ~ A ~ ~ ~ ~  
SYSTEM 
Referring now more specifically to the details of the inven- 
tion, FIG. 2 shows the joined payload and spent motor case as 
it might appear just prior to entering the atmosphere, these 
components being designated generally by the reference nu-  
meral ten. The invention described herein was made by an employee 
of the U.S. Government and may be manufactured and used 
by or for the Government for governmental purposes without 
the payment of any royalties thereon or  therefor. 
This invention relates to a payload separation system, and 
more particularly to a system for separating a payload from a 
spent rocket case prior to reentry of the payload into the at- 
mosphere. 
Various prior art techniques have been used in attempting 
to provide a clean and continued separation of a reentering 
payload from the last-stage motor case. One such technique is 
the use of retrorockets wherein the last-stage motor is 
separated in a direct line from the payload. Although this ar- 
rangement is succcssful to a degree, the mere separation of the 
The payload 12 may take various shapes and forms. the par- 
ticular payload shown being that of one utilized to test the pro- 
perties of an ablation material which has possible use on a 
reentry capsule. 
The payload 12 is joined to a motor case 16 by a clamping 
mechanism 14. The clamping mechanism 14 is of the explo- 
sive bolt type, known in the prior art as a Marmon Band 
clamp. This type clamp utilizes an explosive bolt to release the 
clamping arrangement, and usually has some type of com- 
pressed spring associated therewith, the energy of which 
causes initial separation between the payload and the body 
being separated therefrom. The motor case 16 is a conven- 
tional solid propellant type, having an adapter 18 attached eo 
0 
devices is not always SdtiSfaCt0;y because the payload breaks a 2o the lower portion thereof in the usual manner. 
trail, so to speak, resulting in a last-stage motor case encoun- Affixed to the adapter I8 are retrorockets 2 
tering very little resistance and therefore at times actually retrorockets are of the squib-actuated solid p 
catching up with and colliding with the payload. and are located directly opposite each other on the adapter. It 
Another technique utilized for separating the last-stage has been found by experimentation that the general location 
motor case from the payload is that of a despin technique 25 of the retrorockets as shown in FIG. 2 is advantageous to the 
which also moves the spent motor case out of the path of the separation procedure. However, it should be understood that 
payload. These devices have functioned satisfactorily to a the retrorockets may assume other positions and accomplish 
degree; however, is not always as quick and clean as may be the purpose of the invention. 
desired. Furthermore, the requirement for despinning the FIG. 3 shows a circuit which is utilized to energize the 
spent motor case often requires the need for a spin table 30 retrorockets to accomplish separation of the payload 12 and 
between the payload and spent motor case resulting in addi- the motor case 16. The separation switch 20 is positioned in 
tional structure, expense and questionable reliability. series with a battery 22, the separation switch 2Q being 
The present invention overcomes the above difficulties by designed so that it is closed upon separation of the payload 
providing a technique wherein retrorockets are used to ac- from the motor case. Closing of the separation s 0 
complish separation. The present invention, however, 35 results in the simultaneous closing of switches 6 
eliminates many ofthe prior art difficulties by timing the firing which are in parallel with the battery and in s r  e 
sequence of the retrorockets. The first retrorocket is fired retrorockets 28 and 30, respectively. The particular switches 
causing the spent motor case to move away from the Payload utilized are of the pyrotechnic type which are selected to burn 
and to Cant or a Position at  an angle with respect at different time intervals upon being closed. Thus, the switch 
to the line-of-flight of the payload. While the first retrorocket 40 24 can be set to bur,, immediately and ignite the first 
is still firing, and at  an optimum calculated time, an opposed retrorocket 28, and the other switch 26 is selected to burn a 
retrorocket is fired. The two retrorockets burning together, fraction of a second prior to igniting the second retrorocket. 
then translate the spent motor case out of the path of the Obviously, the switches 24 and 26 could be of some time- 
payload assuring a clean and continued separation ofthe corn- delay type to allow sequential burning of the retrorockets ponents. 
Bt is therefore an object of the invention to provide a 
technique for separating a payload from a spent rocket c a s  
with the use of sequentially timed retrorockets. 
yet another object of the invention is to provide a 
technique for separating a spent rocket 
prior to separation. ing. 
A further object of the invention is to provide separation of 
a spent rocket motor case and a payload wherein the corn- 
ponents utilized for separation are simple to manufacture, 55 and then directed back toward the 
operate and maintain. 
tion technique which is highly reliable and will result in the 
spent rocket motor case being translated out of the flightpath 
of the payload as well as separated from the payload. 
Still another object of the invention is to provide an ar- 
rangement for separating a payload from a spent motor case 
wherein the initial separation of the components initiates the 
separation system. 
will become more apparent upon reading the specification 
taken in conjunction with the accompanying drawings. 
45 thereby accomplishing the purpose of the invention. 
OPERATION 
From the above description of the separation system, it is 
case and a 5o believed that the operation thereof is readily apparent. How- 
ever, the details will be explained to assure ample understand- 
The PafiiCUlar payload utilized with this separation 
technique is normally of the type which is launched into space 
and ac- 
celerated as it returns toward the atmosphere. This is the 
Payload Just Prior to its reentry into the atmosphere. The Pur- 
pose Of obtaining as high a velocity as Possible for the Payload 
60 is also the reason for separating the motor case from the 
Payload. 
AS the Payload enters the atmosphere, the explosive bolt 
mechanism Of the Marmon Band is actuated which allows the 
clamping mechanism to separate. Separation of the com- 
These and other objects and advantages of the invention 65 Ponents of the Clamp is assured bY the SPfing mechanism 
under compression which exerts a pressure against the 
payload and motor case causing initial separation. This closes 
the separation switch 20 which places switches 24 and 26 
across the battery thereby closing the switches. Switch 24 as- 
70 sociated with the first retrorocket 28 is set so that it im- 
mediately ignites the first retrorocket. Since the retrorocket 
28 is placed on one side of the adapter nozzle 
an unbalanced force to the motor case causing it to cant or as- 
sume an angle with respect to the normal flightpath of the 
75 payload as shown in FIG. 1. The second switch 26 after being 
it is not necessary to despin the motor 
An additional object of the invention is to provide a separa- reason why the motor case is Still USUaIiy attached to the 
In the drawings: 
FIG. 11 is an elevational view showing the sequence of 
payload and spent motor case separation; 
FIG. 2 is an elevational view showing the connected payload 
and motor case and the location of the separation system com- 
ponents; and 
FIG. 3 is a schematic diagram of a circuit utilized to ener- 
gize the separation system. 
3,5 3 4,68 6 
3 
closed a time interval, for example, 0.8 seconds, then allows clamping means for connecting said payload means and 
ignition of the second retromotor 30. Sufficient fuel is pro- 
vided in the first rocket motor 28 such that both retromotors means for releasing said clamping means at a selected time; 
21 and 30 burn simultaneously. A balanced force is now ap- a first retro propulsion means attached to said rocket motor 
plied to the motor case 16. and the case is thereby translated 5 means activated upon release of said clamping means; 
out of the path of the payload. and 
It should be apparent that different size retromotors, as well a second retro propulsion means attached to said rocket 
as different time sequences of firing will be necessary depend- motor means actuated subsequent to said first retro 
ing on the size of the payload and motor case, the velocity of propulsion means whereby said rocket motor means is 
the components and other factors. By experimentation it has 10 separated and laterally displaced from said payload 
been shown that the transverse and longitudinal separation means. 
distances versus rime can be readily calculated on commer- 2. A payload rocket motor separation system for a spin-sta- 
cially available computing equipment enabling proper setting bilized vehicle as in claim I wherein said first and second retro 
for retrorocket tiring. propulsion means are solid propellant retrorockets. 
From the above description, it is apparent that the invention 15 3. A payload rocket motor separation system for a spin-sta- 
provides an arrangement for rapid and clean separation of a biked vehicle as in claim 2 wherein said first and second 
payload from a burned-out rocket motor case. By using retrorockets are secured to the adapter of the rocket motor 
retrorockets which are fired at different intervals than simul- means; said first and second retrorockets being positioned on 
taneously, the spent motor case is not only separated but opposite sides of said rocket motor adapter. 
moved out of the path of the payload, thus preventing any pos- 20 4. A Payload rocket motor separation system for a spin-sta- 
sibility of the motor case overrunning and colliding with the bilized vehicle as in claim 1 wherein a separation switch is 
payload. The separation system has few component parts located between said rocket motor means and payload means; 
resulting in a device economical to manufacture and maintain. first and second delay switches closed by the operation of said 
Also, the minimum number of components greatly enhances separation Switch. said separation switch being closed by 
the reliability of the separation technique since there are few 25 release of Said clamping means. 
pieces of mechanism subject to failure. The system is also 5. A payload rocket motor separation system for a spin-sta- 
readily adaptable to various size payloads and motor cases bilized vehicle as in claim 4 wherein said first delay switch in- 
making a particularly versatile arrangement. Since separation itiates said first retro propulsion means and said second delay 
is effectively accomplished without the necessjty of switch initiates said second retro propulsion means. 
despinning the burned-out rocket motor case, the structure 30 6.  A Payload rocket motor separation system for S spin-sta- 
normally required for despinning is eliminated. bilized vehicle as in claim 1 wherein said first retro propulsion 
While a preferred embodiment of this invention has been means burns while said second retro propulsion means is in- 
described, it is understood that modifications and improve- itiated and Operative. 
improvements as incorporate the principles of this invention 35 bilized vehicle as in claim I wherein said first and second retro 
are to be considered in the hereinafler appended claims unless ProPulsion means are activated while said payload and rocket 
these claims by their very language expressly state otherwise. 8. A payload rocket motor separation system for a spin-sta- 
I claim: bilized vehicle as in claim 1 wherein said first retro propulsion 
H. A payload rocket motor separation system for a spin-sta- 40 means upon initiation tips said rocket motor means case to a 
new attitude; and said first and second retro propulsion means 
payload means; move the rocket motor means back and to the side of said 
rocket motor means; payload means. 
rocket motor means; 
menu can be made thereto. Such of these modifications and 7' A payload rocket separation system for a spin-sm- 
are 'pinning. 
bilized vehicle comprising: 
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Payload/burned-out motor case separation system Patent

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