NASA Technical Reports Server (NTRS) 20090015395: Apollo Spacecraft and Saturn V Launch Vehicle Pyrotechnics/Explosive Devices

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by  NASA Technical Reports Server (NTRS)

Apollo Spacecraft & Saturn V
Launch Vehicle Pyrotechnics /
EExxpplloossiivvee DDeevviicceess
Objectives
IIddenttiiffy criittiicall perfformance, ddesiign requiirementts
(cid:137)
and safety measures used to ensure quality,
reliability and performance of the
ppyyrrootteecchhnniicc//eexxpplloossiivvee ddeevviicceess
List and understand the major components and
(cid:137)
ffuunnccttiioonnss ooff aa ttyyppiiccaall AAppoolllloo ppyyrrootteecchhnniicc//eexxpplloossiivvee
device:
Initiators
(cid:190)
CCaarrttrriiddggee AAsssseemmbblliieess
(cid:190)(cid:190)
Detonators
(cid:190)
Core charge
(cid:190)
Identify the major locations/uses for the devices on:
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Command & Service Module (CSM)
(cid:190)
LLuunnaarr MMoodduullee ((LLMM))
(cid:190)(cid:190)
Launch Vehicle (all stages)
(cid:190)
Overview
More than 210 pyrotechnic devices per
(cid:137)
Apollo Mission
Automatically or commanded from the Apollo
(cid:137)
spacecraft systems
(cid:131)(cid:131) OOnnbbooaarrdd
(cid:131) In-flight
(cid:131) Timed
(cid:131) Controlled
All devices required high reliability and safety
(cid:137)
Most devices were classified as either crew
(cid:137)
safety critical or mission critical
Common Uses of Pyrotechnic Devices
PPyrottechhniic ddeviices hhadd a wiidde variietty off applliicattiions:
Launch Escappe Tower ((LET)) sepparation
(cid:137)
Separation rocket ignition
(cid:137)
Booster stage/Lunar Module separation
(cid:137)
FFoorrwwaarrdd hheeaatt sshhiieelldd jjeettttiissoonn
(cid:137)(cid:137)
Spacecraft/Lunar Module Adapter panel separation
(cid:137)
Lunar Module landing gear deployment
(cid:137)
LLunar MModdulle propullsiion systtems pressuriizattiion andd
(cid:137)
activation
Parachute deployment and release
(cid:137)
Electrical circuit opening and closing
(cid:137)
Line/cable cutting – timed & delayed-time
(cid:137)
Sppacecraft vehicle destruction,, if loss of control or
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other catastrophe
Locations – Apollo Spacecraft
See slides under References for detail view
Locations – Launch Vehicle
SSaturn VV LLaunchh
(cid:137)
Vehicle Pyrotechnics
ccoommppoonneennttss
Stage separation
(cid:190)
(cid:131) Retrorockets
(cid:131) Ullage rockets
(cid:131) Detonator blocks
(cid:131)(cid:131) FFiirriinngg UUnniittss
Propellant Dispersion
(cid:190)
System
(cid:131) Not shown – discussed
later
See slides under References for detail view
Requirements, Design/Safety Philosophy
TThhee hhiigghh ssppeecciiffiicc eenneerrggyy ooff ppyyrrootteecchhnniicc mmaatteerriiaallss
(cid:137)(cid:137)
provides a large energy source in a small package
FFuunnccttiioonnss wweerree aaccccoommpplliisshheedd rreelliiaabbllyy aanndd ssaaffeellyy wwiitthh
(cid:137)(cid:137)
minimum weight and space limitations
These ppropperties made wide accepptance of
(cid:137)
pyrotechnics in the Apollo Program a natural result
Conventional electrical and mechanical components
(cid:137)
were used, when possible, to minimize potential
design problems
The quality of explosive materials was crucial - only
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newly-manufactured, specification-controlled
Cyyclotrimethyylenetrinitramine ((RDX)),, Hexanitrostilbene
(HNS), and Lead Azide were used to ensure
consistent quality of the high-explosive materials
Requirements, Design/Safety Philosophy
TTo ensure non-iintterchhangeabbiilliitty off siimiillarlly-shhapedd
(cid:137)
cartridges, an indexing technique which provided
special keyway combinations was developed, and
ddiiffffeerreenntt ssiizzee tthhrreeaaddss wweerree uusseedd oonn tthhee oouuttppuutt eennddss
of the cartridges.
WWhheenn ccoommpplleettee ssyysstteemm rreedduunnddaannccyy wwaass nnoott
(cid:137)(cid:137)
possible, redundant cartridges or single cartridges
with dual initiators were used.
Typically, two separate and electrically independent
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systems operated in parallel and provided complete
rreedduunnddaannccyy iinn tthhee ffiirriinngg cciirrccuuiittrryy.
Apollo pyrotechnic devices ranged from low-energy
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cchhaarrggeess ffoorr ppuunnccttuurriinngg ggaass bboottttlleess ttoo hhiigghh-eenneerrggyy
charges for cutting 0.153-inch-thick steel.
Reliability
TThhe pyrottechhniic saffetty ddesiign relliiabbiilliitty goall was esttabblliishhedd tto bbe
(cid:137)
0.9999 at the 95 % confidence level
Tests of the initiators were pperformed in all apppplicable tyyppes of
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environment & storage conditions to obtain information on the safety
aspects or the no-fire capabilities of a particular device
NNoo ffaaiilluurreess ooff aannyy ppyyrrootteecchhnniicc ddeevviiccee wweerree eevveerr ddeetteecctteedd dduurriinngg aannyy
(cid:137)(cid:137)
of the Apollo missions
Major Components
A typical Apollo explosive device system (or “train”)
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generally consisted of:
IInniittiiaattoorrss - ssttaarrtteedd “ffiirrsstt ffiirree”
(cid:190)(cid:190)
(cid:131) Apollo Standard Initiator & Single Bridgewire Apollo Standard
Initiator
CCaarrttrriiddggee aasssseemmbblliieess - iinnccrreeaasseedd tthhee ppoowweerr ooff tthhee
(cid:190)(cid:190)
initiator
(cid:131) Electrically Initiated & Spacecraft/LM Adapter Thruster
Detonator - initiated the core charge
(cid:190)
(cid:131) Apollo Standard Detonator, End-Detonating Cartridge, &
Long-Reach Detonator
Core charge - completed the explosion started by the
(cid:190)
detonator (big explosion)
(cid:131) Mild Detonatingg Fuse,, Confined Detonatingg Cord,, & Linear
Shaped Charge