May 2013 

NASA/TM–2013-217997 

Guidelines of the Design of Electropyrotechnic 

Firing Circuit for Unmanned Flight and Ground 

Test Projects 

Guillermo A. Gonzalez, Melvin H. Lucy, and Jeffrey J. Massie 

Langley Research Center, Hampton, Virginia 
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May 2013 

NASA/TM–2013-217997 

Guidelines of the Design of Electropyrotechnic 

Firing Circuit for Unmanned Flight and Ground 

Test Projects 

Guillermo A. Gonzalez, Melvin H. Lucy, and Jeffrey J. Massie 

Langley Research Center, Hampton, Virginia 
Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320

443-757-5802 

Acknowledgments 

The authors will like to knowledge Arthur T. Bradley, PhD for his guidance in the 

content and redaction of this technical memorandum. 

The use of trademarks or names of manufacturers in this report is for accurate reporting and does not 

constitute an official endorsement, either expressed or implied, of such products or manufacturers by the 

National Aeronautics and Space Administration. 
Table of Contents 

1. Introduction .............................................................................................................................1

2. Scope ...................................................................................................................................... 1

3. Objectives ...............................................................................................................................2

4. Definitions...............................................................................................................................2

5. Design Approach......................................................................................................................5

5.1. Phase I – Scope of the Product .............................................................................................5

5.1.1. Overall Operational Concept ................................................................................................5

5.1.2. Interface Definition ............................................................................................................... 6

5.1.3. External Interface .................................................................................................................. 6

5.1.4. Internal Interface ................................................................................................................... 6

5.2. Phase II - Requirements, Rationale, Verification and Traceability ...................................... 6

5.3. Phase III – Design Definition ............................................................................................... 6

5.3.1. Firing Circuit Design Safety Requirements .......................................................................... 7

5.3.2. Other Safety Considerations ................................................................................................. 7

5.3.3. Electrical Ladder Diagram .................................................................................................... 7

5.3.4. Electrical Ground Support Equipment ................................................................................ 10

5.3.5. Electroexplosives Checkout Equipment ............................................................................. 13

5.3.6. ALINCO Igniter Tester ....................................................................................................... 13

5.3.7. Blasting Galvanometer ........................................................................................................ 14

5.3.8. Pyrotechnic Voltmeter ........................................................................................................ 14

5.3.9. Personal Protective Equipment (PPE) ................................................................................. 15

5.3.10. Test Facilities, Pyro Bunkers .............................................................................................. 15

5.3.11. Power .................................................................................................................................. 15

5.3.12. Mechanical Design .............................................................................................................. 15

5.3.13. Analysis and Simulation ..................................................................................................... 16

5.3.14. Electroexplosive Devices (EED)......................................................................................... 16

5.3.15. NASA Standard Initiators (NSI) ......................................................................................... 16

5.3.16. Frangible Bolt ..................................................................................................................... 17

5.3.17. Guillotine or Cable Cutter ................................................................................................... 18

5.3.18. Smoke Generator................................................................................................................. 18

5.3.19. Parachute Mortar ................................................................................................................. 18

iii
5.3.20. Pyro Activated Valve .......................................................................................................... 18

5.3.21. Match Squib ........................................................................................................................ 19

5.3.22. Zero Impulse Bolt (ZIB) ..................................................................................................... 19

5.3.23. Sea Water Activated Release System (SEAWARS) ........................................................... 20

5.3.24. Detonator ............................................................................................................................. 20

5.3.25. Safe and Arm Device .......................................................................................................... 21

5.3.26. Firing Circuit Component Selection ................................................................................... 21

5.3.27. Electrical and Electronics .................................................................................................... 22

5.3.28. Cables .................................................................................................................................. 22

5.3.29. Shielding ............................................................................................................................. 22

5.3.30. Crimping and Soldering ...................................................................................................... 23

5.3.31. Connectors .......................................................................................................................... 23

5.3.32. Connector Pin Assignment .................................................................................................. 23

5.3.33. Insulation Resistance ........................................................................................................... 23

5.3.34. Wiring ................................................................................................................................. 23

5.3.35. Wire Routing ....................................................................................................................... 23

5.3.36. Firing Leads ........................................................................................................................ 24

5.3.37. Grounding ........................................................................................................................... 24

5.3.38. Electrical Bonding............................................................................................................... 24

5.3.39. Batteries .............................................................................................................................. 24

5.3.40. Circuit Board and Cable Harness Manufacturing ............................................................... 24

5.3.41. Procedures ........................................................................................................................... 24

5.3.42. Procedure Check Sequence ................................................................................................. 25

5.3.43. RF Silence ........................................................................................................................... 26

5.3.44. Test Points ........................................................................................................................... 26

5.3.45. Verification ......................................................................................................................... 26

5.3.46. Day of Test Procedure ......................................................................................................... 26

5.3.47. Other Procedures and/or Documents .................................................................................. 27

iv
v

                                                                   

                                                                        TABLE OF FIGURES

Figure 1: F/A-18 E/F Drop Model................................................................................................................1

Figure 2: Inflatable Reentry Experiment Vehicle Concept.....................................................................1.

Figure 3: SPLASH Test.............................................................................................................................. 2

Figure 4: Simplified Electrical Ladder Diagram from SPLASH .............................................................8

Figure 5: Simplified Ladder Diagram with GSE Markings from SPLASH............................................9

Figure 6: SPLASH Ground Support Equipment .................................................................................... 10

Figure 7: Zero Impulse Bolt EGSE ..........................................................................................................11

Figure 8: Drop Model Program EGSE Console......................................................................................12

Figure 9: Amptec 601ES Ordnance Meter............................................................................................. 13

Figure 10: ALINCO.....................................................................................................................................13

Figure 11: Blasting Galvanometer...........................................................................................................14

Figure 12: Pyrotechnic Voltmeter ............................................................................................................14

Figure 13: SPLASH NSI Simulator Firing Set Up.................................................................................. 16

Figure 14: NASA Standard Initiator......................................................................................................... 17

Figure 15: Pacific Scientific P/N 92768 Frangible Bolt......................................................................... 17

Figure 16: Holex Cable Guillotine............................................................................................................ 18

Figure 17: IRVE I Pacific Scientific Pyro Valve.................................................................................... ..19

Figure 18: Match Squib Sample................................................................................................................19

Figure 19: Zero Impulse Bolt / UH-1 Interface........................................................................................20 

Figure 20: SEAWARS .................................................................................................................................20

Figure 21: Ensign Bickford Electric Detonator........................................................................................21

Figure 22: Launch Abort System Safe and Arm Device........................................................................21

Figure 23: Test Procedure Sample Page ................................................................................................25
1. Introduction 

The NASA Langley Research Center, Engineering Directorate, Electronic System Branch, is 

responsible for providing pyrotechnic support capabilities to Langley Research Center 

unmanned flight and ground test projects. These capabilities include device selection, 

procurement, testing, problem solving, firing system design, fabrication and testing; ground 

support equipment design, fabrication and testing; checkout procedures and procedure‟s 

training for pyro technicians. 

2. Scope 

The following technical memorandum will serve as a guideline for the design, fabrication and 

testing of electropyrotechnic firing systems. The guidelines will discuss the entire process 

beginning with the project scope‟s definition phase and ending with development and execution 

phases. In this document the following projects will be used as examples to illustrate the 

guidelines: F/A-18 A/E Drop Model Program, Inflatable Reentry Vehicle (IRVE), and Structural 

Passive Landing Attenuation for Survivability of Human-crew (SPLASH). 

Figure 1: F/A-18 E/F Drop Model 

Figure 2: Inflatable Reentry Experiment Vehicle Concept 

1
Figure 3: SPLASH Test 

3. Objectives

The primary objective of this technical memorandum is to capture the design phases, from 

concept to flight. 

The secondary objective is to serve as a guideline for future electropyrotechnic firing circuit

designers. 

4. Definitions 

The following definitions [1] are associated with current NASA Langley Research Center (LaRC) 

operations. 

Arm / Disarm (A/D) Device An electrically or mechanically actuated switch that can 

make or break one or more electroexplosive firing circuits. 

A/D devices do not physically interrupt the explosive train.

There are A/D units which actually interrupt or block the 

explosive train, but are not currently used at NASA LaRC.

Arm Plug A plug that makes the firing circuit continuous when 

inserted in a connector.

Bonding The permanent joining of metallic parts to form an 

electrically conductive path that ensures electrical 

continuity and the capacity to conduct safely any current 

likely to be imposed. The purpose of the bonding is to 

establish an effective path for current that, in turn, 

facilitates the operation of the over current protective 

device.

Bridgewire A resistive element within the electroexplosive device 

which is the final electrical element at the 

electrical/explosive interface.

Catastrophic Hazard A hazard that has the potential for personnel fatality, loss 

of launch site facilities, or loss of reusable or manned 

launch vehicles.

Critical Hazard A hazard that has the potential for personnel injury, 

damage to launch facilities, or damage to reusable or 

manned launch vehicles.

Duding The process of permanently degrading an 

electroexplosive device to a state where it cannot perform 

2
its designated function.

Electroexplosive Device (EED) The first device in an explosive train which is designed to 

transform an electrical stimulus into an explosive reaction. 

Detonators, electrical matches, squibs, exploding bridge 

wires (EBW) devices, NASA Standard Initiator (NSI), 

explosive bolts, cable cutters are examples of 

electroexplosive devices (EED). They are also known as 

pyros.

Electromagnetic Environment The electromagnetic energy (radiated or conducted) to 

which the electroexplosive subsystem will be subjected.

Faraday Cage Also called Faraday screen or Faraday shield. A network 

of parallel wires connected to a common conductor at one 

end to provide electrostatic shielding without affecting 

electromagnetic waves. The common conductor is usually 

grounded.

Firing Circuit A circuit that is composed of the firing source circuit, the 

firing output circuit, the firing control circuit and the monitor 

circuit. (See Typical Firing Circuit Diagram, Figure 4)

Grounding [2] The intentional connection of a current-carrying conductor 

to ground or other electrically conductive material likely to 

become energized to create a permanent, low impedance 

circuit capable of safely carrying the maximum groundfault current likely to be imposed on it from any point in the 

wiring system where ground fault may occur to the 

electrical supply source.

Maximum No-Fire Level The maximum direct current (DC) or Radio frequency (RF)

level at which an electroexplosive device shall not fire with 

a probability of 0.999 at confidence level of 95 percent.

Minimum All-Fire Level The least DC current which causes initiation with a 

probability of 0.999 at a confidence level of 95 percent.

Monitor Circuit Part of the electroexplosive subsystem which indicates the 

status of the firing circuit.

NASA Standard Initiator A 2 pin electrically activated, hot-wire, electro-explosive 

device designed and initially qualified as the Single 

Bridgewire Apollo Standard Initiator (SBASI) to meet the 

requirements of the APOLLO LUNAR MISSION. It was 

subsequently adopted and standardized for use on the 

NASA Space Shuttle System, payloads and other NASAsponsored programs as the NASA Standard Initiator (NSI)

[3]. Its function is to translate an electrical stimulus into 

the production of flame, pressure, and hot particles to 

ignite or initiate a pyrotechnic action or train. It is used 

alone or incorporated into higher level devices in various 

systems associated with the spacecraft's mission. See 

Section 5.3.15 for more information.

Optical Coverage The percentage of the surface area of the cable core 

insulation covered by a shield.

Safe and Arm Device These devices provide for a) mechanical interruption 

(safe) or alignment (arm) of the explosive train, b) 

electrical interruption (safe) or connections (arm) of the 

firing circuits, and c) shorting and grounding of the EED 

3
leads in the safe mode. See Section 5.3.25 for examples.

Safe Plug A plug that shorts EED pins together and connects to 

ground through a resistor which provides electromagnetic 

and electrostatic protection as appropriate. Safe plugs, by 

definition, are used in conjunction with Arm Plugs.

Safe/Arm Plug Safe/Arm plug is a single plug which when installed works 

as an Arm plug and when removed, built-in features of the 

firing circuit perform the same function as a Safe plug.

Safety Device A device which by interruption of the firing circuits or 

explosive train is intended to prevent the inadvertent 

ignition of any explosive device prior to its intended 

operation. The following are examples of safety devices: 

safe and arm devices, safe/arm plugs, arm/disarm 

devices, switches and relays.

Safety Shorting Plug A single plug that when installed shorts all of the EED pins

to prevent inadvert firing it.

Shielding Cap A solid metal outer shell which makes electrical contact 

with the EED case in the same manner as the mating 

connector for the EED. It is attached during storage, 

handling, transporting, and installation. 

Single Point Ground A feature of a power distribution network wherein each 

conductively isolated segment (i.e., transformer-coupled 

or supplied from a separate source) of the distribution 

network has only one physical connection to ground. A 

1MΩ resistor placed between a circuit segment and 

ground does not violate the single point ground concept.

Solid State Relay A semiconductor device with isolated input and output 

which operates by means of electronic components and 

without moving parts. Its primary function is to open and 

close electrical circuits in response to electrical controlling 

signals to effect the operation of other devices in the same 

or other electrical circuits.

Static Bleed Resistor Resistors which are placed between firing circuits and 

ground to prevent built-up of static electricity on circuits.

Switches and Relays These devices open or close circuits when acted upon by 

external stimuli such as electrical signal, physical force, 

material proximity, etc. These devices are normally 

contained in safety devices, but may be used 

independently for making or breaking (interrupting) the 

firing circuit. Switches and relays may be 

electromechanical or solid state.

4
5. Design Approach 

There are three phases in the design of electropyrotechnic firing circuits. Each phase should be 

completed before commencing the next. Phases I and II should not be omitted due to schedule 

constrains. Omitting Phases I and II will eventually result in cost overruns, schedule delay and a 

poor design. 

5.1. Phase I – Scope of the Product

Phase I is an important phase of product development. When properly executed, it prevents 

cost and schedule overruns. During this phase, the designer must meet frequently with the 

Project Manager and Principal Engineer for the purpose of defining the project needs, goals and 

objectives. The project needs are associated with the Agency or Nation needs. The goals and 

objectives flow down from the needs, and are associated with what the product will do and how 

it will develop [4]. In addition, a high level operational concept and interfaces must be defined 

during this phase. For projects like the aircraft Drop Model Program and IRVE need to define, 

the needs, goals and objectives could also be found in the project‟s documentation. For other 

projects like SPLASH‟s need to define, the information could be obtained from the Principal 

Investigator and / or Project Manager. Also, during this phase, it is important to identify critical 

items, the quantity needed, and the product expected delivery date. Critical items example are 

the Electro Explosive Devices, materials, equipment and any other hardware needed for the 

completion of the project. The expected delivery date will help the designer with procurements 

strategy, design drawing release, fabrication, procedure writing, testing and end user‟s training.

It is imperative that all requirements and other criteria be documented in an official project 

document to serve as reference point for the design. 

5.1.1. Overall Operational Concept 

The term operational concept is used to denote a high level description of the product‟s day of 

operations. The description is essential in the development of requirements. For example, in the 

case of SPLASH, the operational concept included the following: 

 Hook up the test article to release cables, activate electropyrotechnic firing box and lift it 

to the drop altitude point.

 Sever capsule‟s pull back cables once it‟s reached a pre-determined drop point.

 Activate frangible bolts to release the capsule at pre-determined release point.

 Release capsule 

 Deactivate electropyrotechnic firing box 

 Recover the capsule. 

A more elaborated and complex example of an overall operational concept is the aircraft Drop 

Model. The following was the operational concept: 

 Attached aircraft drop model to the belly of the helicopter. 

 Activate electropyrotechnic firing boxes 

 Have the helicopter climb to release altitude point. 

5
 Release the model from helicopter‟s Zero Impulse Bolt (ZIB) attachment point. 

 Wait 10 seconds to arm model‟s electronics‟ power, and activate smoke generators. 

 Fly the model remotely. 

 Upon completion of test flight, deploy main parachute using a mortar. 

 Upon water landing use Sea Water Release System (SEAWARS) switch to (a) Cut 

parachute lines, (b) activate flotation system and (c) Cut power in model. 

 Recover the model. 

5.1.2. Interface Definition

It is important to define early on, the external and internal interfaces of the end product. 

Identifying these interfaces will clarify the product scope [4]. All identified interfaces must be 

documented to prevent design oversights. 

5.1.3. External Interface 

Identifying external interfaces early helps to clarify the product scope, aid in risk assessment, 

reduce product development costs, and improve customer satisfaction [4]. The designer lead, 

must identify the end product needs, including power supplies, batteries, battery 

chargers/cyclers, electrical ground support equipment, data acquisition systems, transmitters, 

antennas, receivers, and any other electronic equipment / tools. Mechanical interfaces must be 

identified, as well. This includes, but is not limited to, enclosures, boxes, brackets, pull pins 

and/or safety shorting pins. 

5.1.4. Internal Interface 

As the design moves forward, internal Interfaces need to be identified. In order to avoid 

schedule delays, internal interfaces that require a lengthy procurement lead time must be 

identified early in the design phase. After initial discussions with the project, the designer must 

initiate the necessary hazards permit request to begin the process per NASA Langley Research 

Center Directive LPR 1710.7 Handling and use of Explosive. 

5.2. Phase II - Requirements, Rationale, Verification and Traceability

Once the designer has identified the need, goals, objectives, concepts of operations, and 

interfaces, writing the requirements should begin. A well-defined requirement meets the 

following criteria: necessary, verifiable, and attainable (i.e. technical feasible, within cost and 

within schedule), and traceable to the goals and objectives of the project. The requirements 

control the product outcome. This phase should not be omitted in lieu of working on a design. 

Omitting this phase will lead to requirements creep, cost and schedule overruns. 

5.3. Phase III – Design Definition

This phase should start once the requirements, interfaces and operational concepts are well 

defined and approved. 

6
5.3.1. Firing Circuit Design Safety Requirements 

Safety is the most critical consideration when designing a robust electropyrotechnic firing circuit. 

The firing circuits must meet the following safety requirements: 

1. The firing circuit shall have a minimum of two safety inhibits to prevent premature or 

inadvertent firing. 

2. The firing circuits shall have continuous, twisted, shielded wires from the firing circuit end 

to the ordnance mating connector. The shield shall have 360°shield1

 coverage at the 

ordnance mating connector. 

3. The firing circuits shall have a single point ground. 

4. The firing circuits shall have a 1 MΩ bleed resistor between firing return and structure. 

5. The firing circuits shall have the correct electrical bond between metallic surfaces. 

5.3.2. Other Safety Considerations 

1. Personnel handling pyro devices must be certified. 

2. The use of the proper safety gear is required when handling the pyro devices. 

o This gear consists of safety glasses or face shield, electrostatic discharge 

(ESD) protective smock, and ground strap. 

3. The personnel installing, handling, observing, walking around and/or inspecting 

the EED shall not carry pagers, badges, card keys, cell phones, or other 

transmitting devices. 

4. Pyrotechnic work activities require the presence of a minimum of two individuals: a pyro 

lead and a pyro technician.

5. The electronic equipment‟s calibration must be up to date. 

6. Storage, assembly and test facilities building ground must be annually certified. 

7. The electroexplosive devices (EED) storage cabinets must be grounded to building 

ground. 

8. The operation should be properly safety placarded.

5.3.3. Electrical Ladder Diagram 

An electrical ladder diagram is a power bus diagram that shows the connectivity between 

electronic components from the positive terminal to the return. Figure 4 shows an example of a 

simplified electrical ladder diagram from SPLASH. The diagram illustrates the main components 

of the pyrotechnic firing train connected from the power bus positive terminal to the power bus 

return terminal. The power bus positive terminal is drawn in the left side of the diagram, and the 

return terminal is in the far right of the diagram. The simplified diagram aids in following the 

firing train of the pyro device. When multiple EED are illustrated, one must follow the concept of 

operations in order to understand the sequential firing of each EED.

 

1

 See Section 5.3.29 Shielding for more details 

7
Figure 5 shows an example of a simplified ladder diagram with the ground support equipment 

components highlighted. 

Figure 4: Simplified Electrical Ladder Diagram from SPLASH 

Simplified Firing Diagram 1 second timer Timers time out 1 

second after 

power is applied.

Pin is pulled at the 

same time as FIRE Pin K2

K1

14 Vdc

28 Vdc

FIRE PULL PIN

ARM PULL PIN Timer 1 Contact K1-A

Timer 1 Contact K1-B EB1 - Bridge 1 of 2

EB2 - Bridge 1 of 2

EB3 - Bridge 1 of 2

EB4 - Bridge 1 of 2 1 of 2 Redundant Paths

Only in 1 of the 2 circuit

Pin is pulled at the 

same time as TMR Pin EB – Explosive Bolt

8
Figure 5: Simplified Ladder Diagram with GSE Markings from SPLASH 

TJ2-1A

A B C J1-C

J1-F

J1-J TJ1-1-C

TJ1-1-B

TJ1-1-E

TJ1-1-D J1-M TJ1-1-F

P/J 12d

Bolt 1 Bridge

1 2

Bolt 2 Bridge

1 2

Bolt 3 Bridge

1 2

Bolt 4 Bridge

1 2

P/J7-A

Charge

P/J7-B Charge

TJ1-1-G

P/J6-b

P/J6-d

P/J6-h

P/J6-c

P/J6-e

P/J6-g

P/J6-i P/J 12-c

1 MOHM ESD 

Bleed Resistor

12 NO

1 second Delay J12-b K1BK1A

11 NC

2 NC

5 NC

8 NC

6 NO

9 NO

4 C

1 C 3 NO

10 C

7 C N/C

N/C

N/C

N/C

Power

Sw 1

P/J3-B

P/J3-E

P/J3-H

P/J3-L

P/J3-A

P/J3-D

P/J3-K

TJ1-4-C

TJ1-4-B

TJ1-4-D

TJ1-4-F

TJ1-3-C

TJ1-3-B

TJ1-3-D

TJ1-3-F

TJ1-3-E

TJ1-3-H

TJ1-3-G

TJ1-3-J

P/J6-A

TJ1-3-K

TJ1-4-E

P/J6-C

TJ1-4-A

P/J6-G

J1-A

J1-D

J1-G

J1-K TJ2-1C P/J6-E F G H

TJ2-1B

D

E J

K P/J3-C P/J6-AA P/J3-F P/J6-BB P/J3-J P/J6-CC P/J3-M P/J6-DD P/J6-e P/J3-G P/J1-B

P/J1-E

P/J1-H

P/J1-L

P/J6-B

P/J6-D

P/J6-F

P/J6-H

TJ1-1-A TJ6

A

B

C

D

E

F

G

H

J

K

TJ2-3C

F G H 2 NC

TJ2-4B

D

E JK

3 NO 1 C

4 C

10 C

7 C 8 NC

5 NC

11 NC TJ2-4C

F G H 6 NO

12 NO

9 NO P/J 12-C

P/J 12-D

P/J8B-A

P/J9B-A

P/J10B-A

P/J11B-A

P/J8A-A

P/J9A-A

P/J10A-A

P/J11A-A

P/J8A-B

P/J9A-B

P/J10A-B

P/J11A-B

J/P8B-B

J/P9B-B

 System 1 Power On Indicator

J/P10B-B

J/P11B-B

TJ1-3-A TJ2-6B

D

E J

K

TJ2-6C

F G H

TJ2-7A

A B C

TJ2-7B

D

E J

K

P/J 12-T

P/J 12-U

P/J6-T

P/J 12-V

P/J6-V

P/J 12-B

P/J5-A

TJ2-2A

A B C

P/J5-C P/J5-D

P/J5-B

TJ2-4A

A B C P/J 12-A

P/J6-W

P/J6-U

P/J 12-W

P/J 12-J

P/J 12-K

P/J 12-L

P/J 12-M GSE 

Pyro 1+ GSE 

FIRE 1+ GSE 

ARM 1+

+28 VDC

GND 1

1 Second Time Delay Relay 1

1 Second Time Delay Relay 2

Timer Switch Pin is shown inserted,which is the SAFE condition. Pin is pulled

from ground lanyards at the same time FIRE Pins are pulled.

FIRE Switch Pin is shown inserted,which is the SAFE condition. Pin is pulled from ground lanyards. ARM Switch Pin is shown inserted,which is the SAFE condition. Pin is pulled from ground lanyards.

K1

K2 Battery 1 Opened By Timer Relay TR1

Position controlled by EGSE Master Switch

1

2 3 4 5

1

2 3 4 5

9
5.3.4. Electrical Ground Support Equipment 

The design of the Electrical Ground Support Equipment (EGSE) must occur in parallel with the 

electropyrotechnic firing circuit design. The EGSE will prove to be very useful during ground 

checks and for troubleshooting purposes. The complexity of the EGSE will depend on the 

complexity of the design, the quantity of electro explosive devices (EED) needed for the 

completion of the mission, and the concept of operations. For example, the EGSE for the 

SPLASH (Figure 6) project is much simpler than the one for the Drop Model Program (see 

Figures 7 and 8). The EGSE typically performs the following checks: the firing sequence, EED 

firing test, multipoint checks for resistance, No-Voltage, Continuity, and signal detection. 

 

Figure 6: SPLASH Ground Support Equipment 

10
Figure 7 shows an example of the Drop Model Release EGSE release from the helicopter. 

Figure 7: Zero Impulse Bolt EGSE 

11
Figure 8 shows an example of the Drop Model EGSE for checkout of the model‟s pyrotechnic 

functions. 

Figure 8: Drop Model Program EGSE Console 

12
5.3.5. Electroexplosives Checkout Equipment 

There are several instruments used for the checkout of EEDs and EED firing circuits. Among 

them are the Amptec 601ES Ordnance Meter (Figure 9), ALINCO Circuit Tester (Figure 10), 

blasting galvanometers (Figure 11) and pyrotechnic voltmeters (Figure 12). 

Figure 9: Amptec 601ES Ordnance Meter 

5.3.6. ALINCO Igniter Tester 

The ALINCO Igniter Circuit Tester was developed by the Allegany Company in 1956, and it‟s 

currently manufactured by MB Electronics. The model that is used currently at NASA LaRC is a 

stable, precision instrument designed primarily for the preflight testing of EED bridgewires, 

specifically used for detecting open or short circuit conditions. The circuit of this instrument is a 

modified version of the well-known Wheat Stone Bridge. The Wheat Stone Bridge circuit 

assures the stability and reliability necessary when measuring EED bridgewires resistance. 

Figure 10: ALINCO 

13
5.3.7. Blasting Galvanometer 

The blasting galvanometer (a.k.a blasting galvo) is used to indicate firing circuit continuity. It 

also measures the short circuit back through the EED firing circuit. The short enables the EED 

to remain in a safe configuration by keeping the bridgewire short circuited. Figure 11 shows a 

blasting galvanometer. 

Figure 11: Blasting Galvanometer 

5.3.8. Pyrotechnic Voltmeter 

The pyrotechnic voltmeter is used to verify there is no AC or DC voltage on the EED firing 

circuit. This device shall not contain a battery to prevent accidental firing of the EED during 

checks. The voltmeter must have a label in the front indicating “PYROTECHNIC USE ONLY”, 

and another in the battery compartment indicating “DO NOT INSTALL A BATTERY”. Figure 12

shows a pyrotechnic voltmeter. 

Figure 12: Pyrotechnic Voltmeter 

14
5.3.9. Personal Protective Equipment (PPE)

EED and some electronics are designated as electrostatic discharge sensitive, as such; 

measures to protect personnel against inadvertent firing of the EEDs must take place. Any EED 

sensitive electronics must be labeled as such. Personal Protective Equipment (PPE) includes as 

a minimum: a „static dissipative‟ lab coat or smock, safety glasses or face shield and wrist 

straps. All PPE must be worn when handling and installing the electro-explosive devices (EED). 

The wrist strap shall be grounded to the test assembly. The test assembly must be grounded to 

a common, designated, certified ground system through these procedures. Personnel coming in 

contact with or within 3 feet of any test equipment must wear a wrist strap and lab coat. Wriststraps must be checked with a qualified wrist strap tester prior to use. If wrist straps are 

removed, the check must be repeated. All individuals involved with any operation involving 

EED‟s must be trained to the latest ESD Standard. Any test article consisting of two or more 

metal sections that are separated shall be bonded electrically with ground straps. 

5.3.10. Test Facilities, Pyro Bunkers

The test and pyro bunker facilities must comply with NASA–STD-8719.12 Safety Standard for 

Explosives, Propellants, and Pyrotechnics and NASA NSS 1740.12 Explosive Safety Manual for 

Explosives, Propellants, and Pyrotechnics. The facilities usage includes EED storage, EED 

preparation, and installation into test devices. In the case of the SPLASH project, the facility was 

used to modify the dual bridge frangible bolts by attachment of an appropriate four pin 

connector, and to install the devices in the test article release mechanism. For the Drop Model 

Program, the same facility was used for parachute mortar preparation with the NSI installation, 

and for mortar testing. 

5.3.11. Power 

There are several methods to provide the firing energy required to fire electro explosive devices 

(EED). There are several alternatives for the firing of EEDs; (1) A capacitive discharge bank, or 

(2) a direct battery connection. The use of a capacitive discharge bank is more complex than 

using direct power from a battery. The pyrotechnic firing energy source must be supplied 

independent of the energy source used to power the electronics. The use of a separate battery 

pack is used to guarantee a fully charged pack to fire the EED. 

For the Drop Model Program and SPLASH, nickel cadmium (NICADS) battery packs were used. 

There are other types of battery chemistry that could be used as well. These other sources, 

however, shall be capable of providing the instantaneous current spike needed to fire EEDs. 

5.3.12. Mechanical Design 

The mechanical design aspect for EED systems consists primarily of the EED support brackets, 

mortar, boxes to house the electronics firing circuit, its mounting brackets and pull pin 

assemblies. For the Drop Model program, a mortar assembly was designed and fabricated for 

the release of the main parachute. For SPLASH, a housing assembly was designed and 

fabricated to house the explosive bolts. The Drop Model Program also contained connector 

mounting brackets. 

15
5.3.13. Analysis and Simulation 

For unmanned testing, the analyses are simplistic in nature, and they consist of calculating the 

batteries capacities needed to meet requirements. With respect to simulation, one can simulate 

a day of operation by firing match squibs, NSI simulators, and fuses or by using light bulbs to 

simulate the EEDs. Figure 13 shows SPLASH NSI Simulator firing set up. In this set up, the 

OrCAD Software Version 16.0.0 p001 June 5, 2007 program was used to capture the firing 

signals. 

Figure 13: SPLASH NSI Simulator Firing Set Up 

5.3.14. Electroexplosive Devices (EED) 

The pyrotechnic devices or electro explosive devices (EED) are selected based on the project‟s 

requirements and, are available from various military and space application vendors. Typical 

devices currently being used are Hollex Cable Cutters, NASA Standard Initiators (NSI) and 

frangible bolts. These devices incorporate bridgewires that are rated at 1 watt, 1 amp no fire in 

the initiator. Specifically, the initiator will not ignite when the bridgewire is subjected to a one 

ampere DC for five minutes or a DC power of one watt for five minutes, within the temperature 

range of -260°F to +300°F. 

5.3.15. NASA Standard Initiators (NSI) 

The NASA standard initiator, Type 1, NASA-JSC P/N SEB26100001, is a 2 pin electrically 

activated, hotwire, electroexplosive device designed and qualified initially as the Single 

Bridgewire Apollo Standard Initiator (SBASI) to meet the requirements of the APOLLO LUNAR 

Explosive Bolt Firing Box (EBFB) Alinco

NSI Simulators

Splash

Cable Harness

Labview Interfacing Box

Fire Switches

Arm Switches

Pull Pins Assembly

16
MISSION [3]. It was subsequently adopted and standardized for use on the NASA Space 

Shuttle System, payloads and other NASA-sponsored programs as the NASA Standard Initiator 

(NSI). Its function is to translate an electrical stimulus into the production of flame, pressure and 

hot particles to ignite or initiate a pyrotechnic action or train. It typically produces 900 psi in a 10 

cc closed bomb. It is used alone or incorporated into higher level devices in various systems 

associated with the spacecraft's mission. It uses a fine particle zirconium fuel mixed with a fine 

particle potassium perchlorate oxidizer bound together with a viton rubber binder. It features 

Inconel alloy 718 body construction and hermetic sealing. The NSI can also be hermetically 

sealed (by welding) to the next component. Other features include high electrostatic sensitivity 

protection, internal construction designed for severe vibration protection, a high pressure 

ceramic header, a flush-mounted single stainless steel bridgewire, 1 amp - 1 watt, 5 minute nofire protection and high and low (cryogenic) temperature performance. Figure 14 shows a 

picture of an expended NSI. 

Figure 14: NASA Standard Initiator 

5.3.16. Frangible Bolt 

The frangible bolts are pyrotechnic devices having a 1 amp - 1 watt, 5 minute no-fire protection 

dual bridgewire device. Upon application of current, the bridge wire explosive prime charge is 

activated, and in turn, activates the main charge that generates a shock wave that exceeds the 

ultimate strength of the bolt at a predefined break line. For the SPLASH project we used Pacific 

Scientific P/N 92768 (See Figure 15) rated with an ultimate tensile of 35000 lbs. 

Figure 15: Pacific Scientific P/N 92768 Frangible Bolt 

17
5.3.17. Guillotine or Cable Cutter 

A guillotine or cable cutter is used to sever cables, tubes and/or electrical wires. When severing 

electrical wires with a guillotine or cutter, the possibility of electrical shorting during or after 

operation or both should be considered, and appropriate circuit protection should be provided. 

Figure 16 illustrates the HOLEX model 5803 cable guillotine used in the SPLASH Project. 

Figure 16: Holex Cable Guillotine 

5.3.18. Smoke Generator 

Pyro activated smoke generators are sometimes used as an observable signal tool. For the 

Aircraft Drop Model Program the generators were activated shortly after the model was released 

from the helicopter. The colored (white, orange, or purple) generated smoke provided a tracking 

visual to the ground crew. This bridge-wire equipped cartridge was activated with a 5 amps 

current for 2 milliseconds. When the cartridge was fired, an internal smoke package is initiated 

to begin ejecting orange smoke which appears 0.5 seconds after initiation and continues until 

the charge is exhausted. 

5.3.19. Parachute Mortar 

The parachute mortars are typically used for the deployment of parachutes. For the Drop Model 

Program, the parachute mortar was designed and tested by NASA Langley engineers. Upon 

command, the mortar released the parachute compartment hatch, which in turn released the 

drogue chute which extracted the main parachute. The design contained two (2) NASA 

Standard Initiators. The mortar circuit was also designed to deploy the chute 10-seconds after 

release should there be a detected failure of the model‟s main internal power source. 

5.3.20. Pyro Activated Valve 

Pyro valves are critical for engine chill down in launch vehicle propulsion systems and are used 

for inflation systems. They operate when a firing current is received to either open or close the 

valve. The initiator ignites a booster charge located within the valve body, driving a cutter 

downward to either open or close the flow path. Figure 17 shows the pyro valve used for IRVE I 

project. 

18
Figure 17: IRVE I Pacific Scientific Pyro Valve 

5.3.21. Match Squib 

The match squib is essentially a small bridgewire covered with a small amount of pyrotechnic 

material, and when excited with a 1 amp current, it will fire like a match but with minimum flame. 

The match squib is used in the firing train in lieu of the actual EED during outdoor or bunker 

functional tests. Figure 18 shows an example of a match squib. 

Figure 18: Match Squib Sample 

5.3.22. Zero Impulse Bolt (ZIB)

The Zero Impulse Bolt (ZIB) is a ball–lock release mechanism designed and qualified for use in 

the Minuteman Missile Program by the Air Force. The F/A-18E/F Drop Model Project adopted 

this release system in order to be able to carry/release larger, heavier models from under the 

belly of the UH-1H Helicopter that possessed tall landing gear. The ZIB is inserted into a collar 

that is mounted in the top of the model near its center of gravity. Prior to using the ZIB 

assembly, LaRC personnel successfully axial load tested it to 4500 lb., and the Air Force had 

tested it to 5690 lb. Figure 19 illustrate the ZIB interfaced between the F/A-18E/F Drop Model 

and the UH1 helicopter.

19
Figure 19: Zero Impulse Bolt / UH-1 Interface 

5.3.23. Sea Water Activated Release System (SEAWARS) 

The SEAWARS (Figure 20) was used in the Aircraft Drop Model Program. Upon water landing 

of the aircraft Drop Model, the SEAWARS (Figure 20) with internal battery and exposed switch 

contacts was activated via water emersion to complete the firing path to (a) Cut parachute lines, 

(b) activate flotation system and (c) Cut power in model. 

Figure 20: SEAWARS 

5.3.24. Detonator 

A detonator is most commonly used for the detonation of high explosives. It uses filament wire, 

which is covered with a sensitive ignition mix or prime. The prime will not detonate but ignites a 

booster charge, which will transfer the deflagration (burning) to a detonation (shock wave 

advancing ahead of the burning front) which then detonates the main charge or load. The load 

is sized according to the type of work it needs to perform. This can vary from a simple pressed 

20
cylindrical form to a shape charge, which will direct the shock front. A shape charge will 

normally have an optimum distance from its target where the greatest shock is achieved due to 

overlapping shock waves. A detonator will be found in a high explosive train. Figure 21 shows 

an Ensign Bickford electric detonator. 

Figure 21: Ensign Bickford Electric Detonator 

5.3.25. Safe and Arm Device 

The safe and arm device is used to provide a path that can safe and/or arm the pyrotechnic 

firing train. This device is typically used in launch vehicles. For ground or unmanned testing, 

controllable relays can be used. Pyrotechnic firing circuits must be designed so circuits are not 

armed until necessary. Provisions must be made to disarm pyrotechnic devices promptly when 

no longer needed. Arm and fire must be separate functions that are separately controlled and 

displayed. Manual arm and fire switches must be physically separate and manned by trained 

personnel. Figure 22 illustrate a safe and arm device that was used as a developmental device 

for a future man-rated mission. The device could possibly be used for ground testing projects. 

Figure 22: Launch Abort System Safe and Arm Device 

5.3.26. Firing Circuit Component Selection 

The firing circuit component selection is critical to prevent an overdesign situation. While 

meeting all of the safety requirements, the circuit components and design must be kept as 

simple as possible. Complex design will lead to complex verifications and checkouts. 

21
5.3.27. Electrical and Electronics 

For typical unmanned / ground projects, it is preferable to use electrical and electronic 

components that meet military specifications. These components are more reliable and robust 

than their commercial off the shelf (COTS) counterparts. COTS components are acceptable on 

a case by case basis. EEE parts far exceed the pedigree required; in addition, they are cost 

prohibitive for the typical ground test project. 

5.3.28. Cables 

Electrical cables may be fabricated such that several electroexplosive subsystem circuits are 

contained in a common shielded cable bundle, provided that shielding and isolation 

requirements are met. There shall be no splices used to join elements of ordnance cables. A 

connector shall be provided wherever mating or demating of a circuit is required. All cable runs 

shall be routed as close to a metal structure as feasible. 

5.3.29. Shielding 

 The firing circuit, including the EED2, shall be completely shielded or shielded from the 

EED back to a point in the firing circuit at which isolators eliminate radio frequency (RF) 

entry into the shielded portion of the system. Isolators that provide an attenuation of 

16.8 dB (regardless of source and load impedances) across all frequencies of the 

expected electromagnetic environment shall be considered acceptable. The adequacy 

of the RF protection provided by these isolators can be demonstrated by test or

analysis for each specific usage (i.e., the necessary protection is dependent on the 

configuration of unshielded circuits connected at this point and the expected 

electromagnetic environment).

 Cable shielding shall provide a minimum of 85 percent optical coverage. 

 With the exception of cable shielding, there shall be no gaps or discontinuities in the 

shielding, including the termination at the back faces of the connectors. Also, there shall 

be no apertures in any container which houses elements of the firing circuit. 

 Shields terminated at a connector shall provide 360 degree continuous shield continuity 

without gaps. 

 Shields shall not be used as intentional current-carrying conductors. Multiple point 

grounding of shields to structure is recommended.

 

2

 Some EEDs, for example cable cutters, do not come with twisted shielded wires. Twisting the 

device pigtail without adding shielding is acceptable for applications delineated in this 

document. 

22
5.3.30. Crimping and Soldering 

EED connections should be made using standard stranded wire techniques. Soldering is not 

acceptable because it could change the thermal characteristics of the ordnance. 

5.3.31. Connectors 

All connectors used with the electroexplosive devices shall: 

 Be approved by the procuring activity 

 Have a stainless steel shell or suitable electrically conductive finish 

 Complete the shell-to-shell connection before the pins connect, and provide for 360 

degree shield continuity.

5.3.32. Connector Pin Assignment 

The circuit assignments and isolation of pins within any EES circuit connector shall be such that 

any single short circuit occurring as a result of a bent pin or contamination will not result in more 

than 50 milliamperes or one-tenth of the no-fire current, whichever is less, applied to any 

electroexplosive device. There shall be only one wire per pin. The use of a connector pin as a 

terminal or tie-point for multiple connections is prohibited. Any unused pins in the connectors 

should contain a blank insertion without electrical connections. 

5.3.33. Insulation Resistance

All current carrying components and conductors shall be electrically insulated from each other 

and system ground. The insulation resistance between all insulated parts, at 500 Vdc, 

minimum, shall be greater than 2 megohms, after exposure to the environment specified herein. 

(For the NSI, the potential shall not exceed 250Vdc and only one 250Vdc test shall be 

permitted.) 

5.3.34. Wiring 

Individually shielded twisted pair of wiring shall be used throughout the firing train. Any 

grounding of the firing circuits shall be done at one point only. The return path, on all circuits, 

shall be selected to minimize voltage buildup and transients on the firing circuit return with 

respect to the single point ground. Ungrounded firing output circuits shall be connected to 

structure by a 1 MΩ static bleed resistor in the return line. Structural ground shall not be used as 

return for ordnance circuitry. The source circuits shall terminate in a connector with socket 

contacts. The design shall preclude sneak circuits and unintentional electrical paths. The 

return line shall not be connected directly to the vehicle structure and shall be isolated from 

vehicle direct current (dc) returns through a minimum of 100 kilohms resistance. 

5.3.35. Wire Routing 

The firing circuit wiring shall be routed separately (in separate trays or conduit) from all other 

current carrying circuits including electrical power, electrical control, RF transmission lines, and 

monitoring circuitry. Routing through a single multi-circuit connector does not satisfy this 

requirement. 

23
5.3.36. Firing Leads 

Initiator firing leads shall be configured to prevent incorrect installation. 

5.3.37. Grounding 

The topic of grounding [4] is a broad subject that deals with establishing a low-impedance 

reference for one or more electronic systems. For this technical memo, it is defined as a means 

of referencing electrical circuits to a well-bonded equipotential surface. The electrical circuits 

must have a single point ground reference. 

5.3.38. Electrical Bonding 

Electrically initiated pyrotechnic devices or those containing primary explosives shall be 

designed so that electrical resistance between the metal exterior of the device and the next 

adjoining device or contact surface, if mechanically joined, shall be 2.5 milliohms or less. 

Reefing line cutters are exempt from this requirement. 

5.3.39. Batteries 

The use of commercial off the shelf (COTS) batteries is acceptable as power source 

components for electronics and/or firing EEDs. Typical chemistry includes Lithium Ion, Lithium 

gel, Lithium Polymer, and Nickel Cadmium.

With respect to sizing the battery capacity, a good best practice is that it must meet the mission 

capacity requirement with at least 25% capacity margin. 

Unless otherwise specified, typical EEDs are designed to withstand a constant, direct current 

firing pulse of up to 1 ampere and 1 watt power (minimum) for a period of 5 minutes (minimum) 

duration without initiation or deterioration of performance (i.e. duding). 

Laboratory testing of the EED has shown that typical firing minimum conditions are: an all-fire 

bridgewire current level of 3.5 amps for 6 milliseconds; or an all-fire voltage level of 6.5 volts 

across the bridgewire for 6 milliseconds. Therefore, the EED firing battery must be sized 

accordingly. 

5.3.40. Circuit Board and Cable Harness Manufacturing 

For the manufacturing of harnesses, circuit boards, enclosures, and support brackets, the latest 

approved NASA Standards and best practices apply. 

5.3.41. Procedures 

The number of procedures needed for a successful test campaign is dependent on the design 

complexity. This should not be a deterrent from having a set of well written procedures. The 

procedure should be written clearly, and divided in sections. Each procedural step shall contain 

only one instructional step, written as a complete sentence. Having multiple instructions in one 

step produces a potential risk of missing a step during the execution of the procedure. Each line 

of the procedure should have a signoff check point at the end of the sentence. Also, each page 

of the procedure should have a set of signoff lines for the Operational Safety Supervisor (OSS) 

24
and the two pyrotechnic technicians who are running the procedure. Figure 23 shows a sample 

page of such a procedure. 

Figure 23: Test Procedure Sample Page 

There are several types of checkout procedures required during the build-up of a project. These 

include but are not limited to pyro assembly build-up, simulation test procedure, and / or test 

verification procedures. 

5.3.42. Procedure Check Sequence 

There is a sequence of procedural steps that must be followed to ensure that the firing circuits 

are safe both before and after installation of the EED. Prior to commencing the checkout 

25
procedure, the battery must be fully charged and tested with a 2 minute load test. This simple 

test will demonstrate that the energy source is capable of completing the upcoming test. The 

steps start with the verification that the electroexplosive checkout equipment has its calibration 

up to date followed by a confidence check of the ALINCO and blasting galvanometer. The 

subsequent steps are as follows: no-volts check, resistance measurement, functional check, 

post-functional no-volt checks, EED installation and EED firing path check. 

The first no-volts check is done to make sure that there is no stray DC or AC voltage in the firing 

circuits. The resistance measurement is done to make sure that the firing path impedance has 

not changed. The measurement is compared against the baseline measurement that was taken 

after all harnesses and circuits have been fabricated. The functional check consists of a 

simulated firing sequence test. Fast blow fuses, circuit breakers, match squibs, NSI simulators, 

or light bulbs could be used in lieu of the EED. The purpose of the functional test is to make 

sure that the entire firing circuit is ready for the test. After completion of the functional test, a novolts check followed by a resistance check must be repeated to make sure that the EED can be 

installed safely. After installing the EED, the firing path resistance must be measured to verify 

that a full path to the EED exists. In order to prevent an inadvertent firing, it is imperative to 

make the resistance measurement with the firing circuit power source disconnected. The 

resistance measurement will be compared against the baseline measurement. 

5.3.43. RF Silence 

Prior to the installation of EEDs, all types of RF transmission must be stopped. This includes 

walkie-talkies, cell phones, electronic badges, pagers, and PA systems. The rationale for having 

RF silence during the EED installation is to prevent misfiring due to unwanted signals. 

5.3.44. Test Points 

The firing circuit design should have test points. These test points are brought out through the 

electrical ground support equipment (EGSE) connector. The locations of the test points are 

strategically selected from the firing circuit path and include the positive and return power bus 

lines, Safe and Arm contacts, and the EED elements. 

5.3.45. Verification 

The requirements verification is typically done throughout the build-up phase of the project. The 

verification process starts with the Preliminary Design Review, and it is completed at the test 

“dress rehearsal”. 

5.3.46. Day of Test Procedure 

The Day of Test Procedure contains various phases, and it is typically controlled by the Test 

Director and a Master Test Procedure. For the EEDs, this procedure contains a wiring harness 

integrity check, no volts checks, firing circuit no-volts check, firing circuit resistance 

measurements, functional checks and EED installations, test sequence, and posttest 

operations. 

26
5.3.47. Other Procedures and/or Documents 

Throughout the life of the project, there is a possibility that build up procedures are required. For 

instance, in the case of SPLASH, a procedure was written for the installation of connectors to 

the frangible bolt bridge wires. Another procedure was written for the installation of the frangible 

bolts into the test article release mechanism, and installation of the final release assemblies into 

the test article. 

27
References 

1. Military Standard 1576 Electroexplosive Subsystem Safety Requirement and 

Test Methods for Space Systems 

2. Bradley Arthur T., A Methodology for Designing Low-noise Electronics Systems

3. NASA Standardization of the SMSI/SBASI Pyrotechnic Initiator; Report of the 

Study Team; June 1974. The authors were: R. A. Wasel, NASA HQ; M. H. Lucy, 

LaRC; W. H. Simmons, JSC; and A. J. Murphy, JPL 

4. Hooks Ivy F. & Farry Kristin A., Customer-Centered Products, New York, 

American Management Association, 2001 

5. NASA –STD-8719.12 Safety Standard for Explosives, Propellants, and 

Pyrotechnics 

6. NASA NSS 1740.12 Explosive Safety Manual for Explosives, Propellants, and 

Pyrotechnics 

7. NASA Langley Research Center Directive LPR 1710.7 Handling and use of 

Explosive 

8. NASA Wallops Flight Facility, Ordnance Training Manual (Handling, Safety and 

Circuitry), Revision F, April 2009 

9. JSC 62809 Rev D Constellation Spacecraft Pyrotechnic Specification 

10. Handbook of Pyrotechnics, Karl O. Brauer, Chemical Publishing Co, Inc. New 

York, New York, 1974 

28
REPORT DOCUMENTATION PAGE Form Approved

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2. REPORT TYPE 

Technical Memorandum

 4. TITLE AND SUBTITLE

Guidelines of the Design of Electropyrotechnic Firing Circuit for 

Unmanned Flight and Ground Test Projects 

5a. CONTRACT NUMBER

 6. AUTHOR(S)

Gonzalez, Guillermo A.; Lucy, Melvin H.; Massie, Jeffrey J.

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center

Hampton, VA 23681-2199

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National Aeronautics and Space Administration

Washington, DC 20546-0001

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NASA

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14. ABSTRACT

The NASA Langley Research Center, Engineering Directorate, Electronic System Branch, is responsible for providing 

pyrotechnic support capabilities to Langley Research Center unmanned flight and ground test projects. These capabilities 

include device selection, procurement, testing, problem solving, firing system design, fabrication and testing; ground support 

equipment design, fabrication and testing; checkout procedures and procedure’s training to pyro technicians. This technical 

memorandum will serve as a guideline for the design, fabrication and testing of electropyrotechnic firing systems. The 

guidelines will discuss the entire process beginning with requirements definition and ending with development and execution. 

15. SUBJECT TERMS

Electroexplosive devices; Electropyrotechnics firing circuits; Pyrotechnics

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