lunar module ecs - nasa system (ecs) generic designcontrol system (ecs) generic design...

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

Overview of LM ECS

Oxygen Supply and Cabin P i tiPressurization Section

Overview of LM ECS

Atmosphere Revitalization section

Overview of LM ECS

Water Management Section

Overview of LM ECS

Heat Transport Section

Generic Design Considerations

ReliabilityFlight InstrumentationModularizationThe change from fuel cells to batteries

Conrad & Bean

Generic Design Considerations -- Reliability

Reliability

Aldrin


“Perfect” is the enemy of “good enough”

Aldrin


“Perfect” is the enemy of “good enough”Redundancy

Aldrin


“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failure

Aldrin


“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failureShelf-life control

Aldrin


“Perfect” is the enemy of “good enough”RedundancyCause & effect analysis vs. mean time to failureShelf-life controlFailure reporting

Aldrin

Generic Design Considerations –Flight Instrumentation

ReliabilityFlight Instrumentation

Schmitt


Minimum needed to monitor performance

Schmitt


Minimum needed to monitor performanceControl position telemetry switches

Schmitt



Most not needed

Schmitt



Most not neededSwitch plunger travel length

Schmitt



Most not neededSwitch plunger travel lengthDifficult to install

Schmitt

Generic Design Considerations – Modularization

ReliabilityFlight InstrumentationModularization

Armstrong


Modularized by subsystem

Armstrong


Modularized by subsystemDense packaging

Armstrong


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


Change to high pressure oxygen vs. LOX

Cernan & Stafford


Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stage

Cernan & Stafford


Change to high pressure oxygen vs. LOXVery high pressure/high capacity O2 tank in descent stageStaging and cutter assemblies (guillotine)

Cernan & Stafford


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




No retention mechanismmechanism

No risk of impactNo risk of impact ignition



Original design

Cernan & Stafford

Generic Design Considerations – Original QDs


Poppet seal was on the ascent t tistage portion


Exterior leak path seal was on the d t tdescent stage portion


Redundant seal was needed on th l l lthe glycol loop because it leakedleaked

Not needed on the oxygen QDoxygen QD


Very susceptibleto installationdamage


Very susceptibleto installationdamageExternal leak path seal can impact here


Very susceptibleto installationdamagePoppet seal can be impacted by head of descent t tistage portion



Original designFinal design

Cernan & Stafford

Generic Design Considerations – Final QDs


Built inredundancy


Highly resistant toinstallationdamage

The poppet seals p ppare protectedbehind metal


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.


General Testing -- Feasibility

Feasibility


FeasibilityOriginal concept to use pre-production hardware


FeasibilityOriginal concept to use pre-production hardwareTests conducted on component, logic group, and system levelssystem levels


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

FeasibilityDesign verification


Design verificationPerformance


Design verificationPerformanceStructural


Design verificationPerformanceStructuralL k / t bilitLeakage/stability


Design verificationPerformanceStructuralL k / t bilitLeakage/stabilityEndurance

General Testing -- Qualification

FeasibilityDesign verificationQualification


QualificationDesign limit testing


QualificationDesign limit testingEMI


QualificationDesign limit testingEMIVib tiVibration


QualificationDesign limit testingEMI Vib tiVibrationFunctional


QualificationDesign limit testingEMI Vib tiVibrationFunctionalEnduranceEndurance


QualificationDesign limit testingEMI Vib tiVibrationFunctionalEnduranceEnduranceIntegration and checkout

General Testing – Man Rating

FeasibilityDesign verificationQualificationIntegrated Subsystems & Vehicle (Man-Rating)


Integrated Subsystems & Vehicle (Man-Rating)Unmanned


Integrated Subsystems & Vehicle (Man-Rating)UnmannedManned (contractor)


Integrated Subsystems & Vehicle (Man-Rating)UnmannedManned (contractor)M d ( t t )Manned (astronauts)


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


Thermal-vacuumLTA-8 cold case


Thermal-vacuumLTA-8 cold caseLTA-8 hot case


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.


References

Apollo Experience Report – Lunar Module Environmental Control SubsystemWiki on this website: http://modspops.jsc.nasa.gov/mod/DA4/CxTraining/Apollo/Apollo%20Wiki/Home aspxng/Apollo/Apollo%20Wiki/Home.aspx

M f f d d li k b lMore references found under link below

lunar module ecs - nasa system (ecs) generic designcontrol system (ecs) generic design...

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