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Lunar Module ECSLunar Module ECS((Environmental Control System)Environmental Control System)((Environmental Control System)Environmental Control System)
Design Considerations & Failure ModesDesign Considerations & Failure Modes
Part IPart I
https://ntrs.nasa.gov/search.jsp?R=20090016294 2018-07-12T08:38:16+00:00Z
Objectives
Upon completion of the lesson, the student will be able to:able to:
Describe the Lunar Module (LM) Environmental Control ( )System (ECS) generic design considerations philosophy.
Summarize the LM ECS general testing regime.
Prerequisite
For the best understanding of this material, the student should have viewed the Lunar Module (LM) Environmental Control System (ECS) Familiarization lesson prior to viewing thisFamiliarization lesson prior to viewing this lesson.
Overview of LM ECS
Oxygen Supply and Cabin Pressurization SectionAtmosphere Revitalization SectionWater Management SectionHeat Transport Section
Generic Design Considerations
ReliabilityFlight InstrumentationModularizationThe change from fuel cells to batteries
Conrad & Bean
Generic Design Considerations -- Reliability
“Perfect” is the enemy of “good enough”Redundancy
Aldrin
Generic Design Considerations -- Reliability
“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failure
Aldrin
Generic Design Considerations -- Reliability
“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failureShelf-life control
Aldrin
Generic Design Considerations -- Reliability
“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failureShelf-life controlFailure reporting
Aldrin
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Schmitt
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Most not needed
Schmitt
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Most not neededSwitch plunger travel length
Schmitt
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Most not neededSwitch plunger travel length
Schmitt
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Most not neededSwitch plunger travel lengthDifficult to install
Schmitt
Generic Design Considerations –Flight Instrumentation
Minimum needed to monitor performanceControl position telemetry switches
Most not neededSwitch plunger travel lengthDifficult to install
Schmitt
Generic Design Considerations – Modularization
ReliabilityFlight InstrumentationModularization
Armstrong
Generic Design Considerations – Modularization
Modularized by subsystemDense packagingReplacement in the field
Armstrong
Generic Design Considerations –The Change to Batteries
ReliabilityFlight InstrumentationModularizationThe change from fuel cells to batteries
Cernan & Stafford
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOX
Cernan & Stafford
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stage
Cernan & Stafford
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stageStaging and cutter assemblies (guillotine)
Cernan & Stafford
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stageStaging and cutter assemblies (guillotine)Interstage quick disconnects (QDs)
Cernan & Stafford
Generic Design Considerations – QDs
Cutoff valves not needed, as will
t ti llautomatically seal
No retention mechanismmechanism
Generic Design Considerations – QDs
Cutoff valves not needed, as will
t ti llautomatically seal
No retention mechanismmechanism
No risk of impactNo risk of impact ignition
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stageStaging and cutter assemblies (guillotine)Interstage quick disconnects (QDs)
Original design
Cernan & Stafford
Generic Design Considerations – Original QDs
Exterior leak path seal was on the d t tdescent stage portion
Generic Design Considerations – Original QDs
Redundant seal was needed on th l l lthe glycol loop because it leakedleaked
Not needed on the oxygen QDoxygen QD
Generic Design Considerations – Original QDs
Very susceptibleto installationdamageExternal leak path seal can impact here
Generic Design Considerations – Original QDs
Very susceptibleto installationdamagePoppet seal can be impacted by head of descent t tistage portion
Generic Design Considerations –The Change to Batteries
Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stageStaging and cutter assemblies (guillotine)Interstage quick disconnects (QDs)
Original designFinal design
Cernan & Stafford
Generic Design Considerations – Final QDs
Highly resistant toinstallationdamage
The poppet seals p ppare protectedbehind metal
Generic Design Considerations – Final QDs
Better protection tothe sealingsurfaces
Exterior leak pathpseals embeddedin groovesg
Objectives
Upon completion of this part of the lesson, the student will be able to:student will be able to:
Describe the Lunar Module (LM) Environmental Control ( )System (ECS) generic design considerations philosophy.
Summarize the LM ECS general testing regime.
General Testing -- Feasibility
FeasibilityOriginal concept to use pre-production hardwareTests conducted on component, logic group, and system levelssystem levels
General Testing -- Feasibility
FeasibilityOriginal concept to use pre-production hardwareTests conducted on component, logic group, and system levelssystem levelsPre-production hardware very much resembled eventual production hardware, reducing the need p , gfor design verification testing
General Testing – Design Verification
Design verificationPerformanceStructuralL k / t bilitLeakage/stability
General Testing – Design Verification
Design verificationPerformanceStructuralL k / t bilitLeakage/stabilityEndurance
General Testing -- Qualification
QualificationDesign limit testingEMI Vib tiVibrationFunctionalEnduranceEndurance
General Testing -- Qualification
QualificationDesign limit testingEMI Vib tiVibrationFunctionalEnduranceEnduranceIntegration and checkout
General Testing – Man Rating
FeasibilityDesign verificationQualificationIntegrated Subsystems & Vehicle (Man-Rating)
General Testing – Man Rating
Integrated Subsystems & Vehicle (Man-Rating)UnmannedManned (contractor)
General Testing – Man Rating
Integrated Subsystems & Vehicle (Man-Rating)UnmannedManned (contractor)M d ( t t )Manned (astronauts)
General Testing – Man Rating
Integrated Subsystems & Vehicle (Man-Rating)UnmannedManned (contractor)M d ( t t )Manned (astronauts)Special
General Testing – Thermal Vacuum
FeasibilityDesign verificationQualificationIntegrated Subsystems & Vehicle (Man-Rating)Thermal-vacuum
General Testing – Thermal Vacuum
Thermal-vacuumLTA-8 cold caseLTA-8 hot caseLTA 8 l l di iLTA-8 lunar landing sim
General Testing – Vehicle and Acceptance
FeasibilityDesign verificationQualificationIntegrated Subsystems & Vehicle (Man-Rating)Thermal-vacuumVehicle and Acceptance
Review of Objectives
Describe the Lunar Module (LM) Environmental Control System (ECS) generic designControl System (ECS) generic design considerations philosophy.
Summarize the LM ECS general testing regime.