33
Page 1 Clouds and the Earth’s Radiant Energy System RBI Instrument Overview Kory Priestley, RBI Project Scientist Mohan Shankar, Deputy PS – Calibration Anum Barki, Deputy PS - Modeling
Page 1
Clouds and the Earth’s Radiant Energy System
RBI Instrument OverviewKory Priestley, RBI Project Scientist
Mohan Shankar, Deputy PS – CalibrationAnum Barki, Deputy PS - Modeling
Page 2
Radiation Budget Instrument
ScienceGoal• Tocontinue themeasurementsfromthelasttwodecadesin
supportofglobalclimatemonitoring.• RBIextends theEarthradiationbudgetmeasurementsofthe
EarthObservingSystem(EOS)andJointPolarSatelliteSystem(JPSS)
• NASA/NOAAPartnership– NOAAprovidesJPSS-2satelliteforaccommodationofRBI– NASAprovidesRBIinstrumentandsupportthroughspacecraftI&Tandlaunch/activation– NASAfundsradiationbudgetsciencedataanalysisandgenerationofscienceproducts(RBMProject)
• NASALangley– ManagesprimecontractordevelopmentofRBIinstrument,providesmanagement,technical,andmissionassuranceinsightandoversight;providessupporttospacecraftI&Tthrulaunchandearlyon-orbitcheckout(thruPhaseD)– Hand-overandreleaseofRBIinstrumentownershipbyRBIProjectoccursattheJPSS-2OperationalHand-overReview(OHR).ForPhaseE,theLangleyScienceDirectorate(SD)RadiationBudgetMeasurement(RBM)ProjectassumesresponsibilityforRBIformissionplanningandoperations• HarrisCorp.– RBIInstrumentprovider/primecontractorwithsub-contractorsprovidingkeyelementsandsupport(SDLforCalibration,JPLforThermopileDetectors,SierraNevadaforAzimuthRotationModule)
• JPSS-2SpacecraftandMissionInterface-- InterfaceControl(ICD&MICD)andDataFormat
PartnershipsandTeams
RadiationBudgetInstrument(RBI)RBIscanningradiometermeasuringthreespectralbandsattopofAtmosphere(TOA)• Total0.3to>50+m• Shortwave0.3to5.0m• Longwave5.0to50+m
µµ µ
RBI is a New Instrument Developed as a Follow-on to CERES Flown on TRMM, EOS, NPP, and JPSS-1
• Phase:Formulation(C)• Risk:7120.5E,Category2;8705.4PayloadRiskClassB• FlightInstrumentDelivery: March2019• JPPS-2On-dockDeliveryDate: April2019• Life:7years
RBI is a CERES Data Continuity Mission
Page 3
Radiation Budget Instrument
Partnerships and Teams
Page 4
Radiation Budget Instrument
RBI Baseline and Threshold Requirements
KeyPerformanceRequirements BaselineScienceRequirements ThresholdScienceRequirements
TotalSpectralRange 0.3to100+microns 0.3to50+ microns
ShortwaveSpectralRange 0.3to5microns 0.3to5microns
LongwaveSpectralRange 5to50+microns 5to35+ microns
TotalChannelAbsoluteRadiometricAccuracy ≤Largerof0.575W/m2-sror0.5%(k=1)
≤Largerof0.575W/m2-sror0.75% (k=1)
ShortwaveChannelAbsoluteRadiometricAccuracy
≤Largerof0.75W/m2-sror1.0%(k=1)
≤Largerof0.75W/m2-sror1.25% (k=1)
LongwaveChannelAbsoluteRadiometricAccuracy
≤Largerof0.575W/m2-sror0.5%(k=1)
≤Largerof0.575W/m2-sror0.75% (k=1)
TotalChannelRadiometricPrecision ≤0.2W/m2-sr+0.1%(k=3)
≤0.2W/m2-sr+0.1%(k=2)
ShortwaveChannelRadiometricPrecision ≤0.2W/m2-sr+0.1%(k=3)
≤0.2W/m2-sr+0.1%(k=2)
LongwaveChannelRadiometricPrecision ≤0.2W/m2-sr+0.1%(k=3)
≤0.2W/m2-sr+0.1%(k=2)
TotalChannelLinearity ≤1.5W/m2-sr ≤2.5W/m2-sr
ShortwaveChannelLinearity ≤1.28W/m2-sr ≤2.13W/m2-sr
LongwaveChannelLinearity ≤0.54W/m2-sr ≤0.9W/m2-sr
PointSpreadFunction Within95%ofCERES Within90%ofCERES
RBI Baseline Science Requirements Match CERES
Page 5
Radiation Budget Instrument
RBI Accommodated on JPSS-2 Spacecraft Nadir Deck
RBI+ X (Velocity)
+ Z (Nadir)
+Y
JPSS-2InstrumentComplement• RadiationBudgetInstrument(RBI)• AdvancedTechnologyMicrowaveSounder(ATMS)• Cross-trackInfraredSounder(CrIS)• VisibleInfraredImaginingRadiometerSuite(VIIRS)• OzoneMappingandProfilerSuite(OMPS)
SpacecraftdesignandInstrumentlocationsarenotionalandrepresentativeofJPSS-1JPSS-2configurationhasnotbeendetermined
JPSS-2Observatory•NominalAltitude:824km± 17km•GroundTrackRepeatabilityAccuracy:±20kmattheequator•GroundTrackRepeatCycle:<20days•NominalAscendingEquatorCrossingTime:1330(localtime)± 10min
Page 6
Radiation Budget Instrument
Instrument Overview
¨ Instrument Design Overview§ Instrument Features§ ConOps Overview§ Module Overviews
¨Performance Overview¨Engineering Development Unit Overview
Radiation Budget Instrument
Page 7
Science and Continuity Drive Key Features of RBI Design
RBIScienceNeeds RBIDesign FeaturetoFulfillScienceNeedLowShortwaveRadiometricUncertainty
VCT containingElectricalSubstitutionRadiometer(ESR)providesstableSWreferenceradianceoverlife
LowTotalandLongwaveRadiometricUncertainty
Heatedhigh-emissivityICTwithwell-calibratedtemperaturesensorsprovideon-orbitreferenceforTotalandLWchannels
AccurateKnowledgeofRelativeSpectralResponse OverLife
6-diodeVCT providesmultispectralRSRcharacterizationwithabsolutestabilityprovidedbytheESR
RadiometricCalibrationConsistencyBetweenChannels All channelsviewthesameVCT,ICT andSCT.
StableRadiometricResponse Effectivetemperaturestabilityoftelescope anddetectorsPointSpreadFunction(PSF)CloselyMatchesHeritageCERES
RBIusesanIFOV size/shapeandscanratethatarenearlyidenticaltoheritageCERES.PSFclosely matchesCERES.
RadiometricVerificationViaSolarCalibration
SCT containingmultipleSpectralon surfaces.Pristinesurfacesareusedtodetectdegradationofprimarysurface.
MultipleObservationModes(crosstrack,bi-axial, userdefined)
3telescopes (oneforeachband)providebestoperationalflexibilityandcontinuity.Uploadable scanpattern.
Reliable ScienceData Completelyredundant instrument,includingdetectorsandelectronics
VCT =VisibleCalibrationTargetICT =InfraredCalibrationTarget
SCT =SolarCalibrationTarget
Page 8
Radiation Budget Instrument
RBI ConOps Provides Operational Flexibility
¨Earth observations: Crosstrack and Biaxial scanning¨Calibration
§ Every scan line: space look§ Daily: single point gain response using VCT and ICT§ Monthly
• Spectral calibration using VCT• Linearity measurement using VCT and ICT
¨User-defined modes for operational flexibility § Earth target for validation campaigns
• Includes cross-correlations with CERES by viewing the same earth location
§ Solar observations via diffuse target§ Lunar observations
Page 9
Radiation Budget Instrument
Field of Regard Obtained by Mounting Orientation & Two-Axis Pointing
Cross-trackScanModule(CSM)enablesswathmodeviewsoftheEarth,internalcalibrationtargets,andspaceviews
AzimuthRotationModule(ARM)enablesbiaxial-modeforviewsoftheEarthtosupportAngularDistributionModels(ADM),directLunarcalibration,andindirectSolarcalibrationusingtheSolarCalibrationTarget(SCT)
+X
+Y
+Z (Nadir)
Radiation Budget Instrument
Page 10
Cross-Track Scan is Primary Operational Mode
Constant63.1deg/secrateoverfullEarth;6.6-seccycle
time
Earth
Space (Cal)
Space (No-Cal)Spacelook 1 Spacelook 2
Page 11
Radiation Budget Instrument
Bi-Axial Scan Mode SupportsRefinement of Angular Distribution Models
¨During a Bi-axial scan the instrument is commanded to rotate both the azimuth and Elevation gimbals§ Data is used to validate and refine
Angular Distribution Models used to convert RBI radiances into fluxes at top of atmosphere
¨Elevation scan rate is 63.1 deg/sec with a +/- 70 deg rotation
¨Azimuth scan rate is 0.5 to 6.0 deg/sec with a +/-90 deg rotation
¨Azimuth scan rate and rotation are commanded from ground
Example: Azimuth scan rate is 0.5 deg/sec
Radiation Budget Instrument
Page 12
Modular Design Simplifies Integration
ElectronicsUnit(EU)
Cross-TrackScanModule(CSM)
AzimuthRotationModule(ARM)
ThermalMountingFeet
BenchShroud
SolarCalibrationTarget(SCT)
InfraredCalibrationTarget(ICT)
OpticalModule(OM)
VisibleCalibrationTarget(VCT)
ExternalFilterModule
TwistCapsule
LaserDiodeAssembly
ESRElectronics
TwistCapsuleMountingBracket
CSMAssembly
Radiation Budget Instrument
Page 13
Optical Modules and Targets Designed for Maximum Stability and Accuracy
ICTHeated,High-Emissivity SCTWith3Protected
Spectralon®Surfaces
VCTWith6-WavelengthRadianceOutputandESRforAbsoluteReference
NADIR0o (+Z)
SWLW
Total
ThermalShroudsMinimize
TemperatureDrifts
TelescopeBafflingMinimizesStrayLight
ThermopileDetectors;ShapeProvidesHeritagePSF
Radiation Budget Instrument
Page 14
Optical Module Controls Stray Light While Providing a Stable Thermal Environment
Fore-Baffles
TelescopeMirrors Filter
JPLThermopileDetector
OpticalModule
ExtensiveTelescopeBafflingMinimizesStray
Light
MaterialsMinimizeThermal
GradientsRearEnclosureProvides
ThermallyStableEnvironment
OneTelescopePerBandSimplifiesDetectorDesign
Radiation Budget Instrument
Page 15
JPL Thermopile Detectors Enable Data Continuity with CERES
¨ Uncooled thermopile detectors with Gold-Black coating are responsive over the full RBI spectral range from UV to far-infrared§ Scene radiance is measured by detecting
small changes in temperature of the detector material
¨ Detectors are highly linear, stable, low noise, and fully redundant
¨ Heritage: MCS/Diviner (15 years of flight ops)
Requirement Value Compliance
SpectralResponse Specified over0.2-100microns Yes
DynamicRange 0-600W/m2/sr Yes
Gain 22,000V/W+/-10% Yes
Gain TempCoefficient <220V/W/K Yes
Reliability(glintsurvival) 3.81 mW, 30times Yes
Non-linearity <0.04% Yes
ResponseUniformity +/-5%3x75umspot Yes
Outoffieldresponse <0.01% Yes
NoiseEquivalentPower <3nW Yes
Timeconstantmax <9.0msec Yes
Timeconstantmin >7.5msec Yes
OutputStability <0.5nWfor6.6sec Yes
Page 16
Radiation Budget Instrument
ICT is a Thermal Infrared Radiance Source for Precise Calibration
¨Provides IR calibration source for LW and Total channels
¨Harris-patented Specular Trap design provides >0.995 emissivity in a compact, easy to manufacture package
¨PRTs are carefully calibrated to NIST standard on the ground prior to installation
¨Heaters enable linearity measurements while on-orbit
¨Beryllium minimizes thermal gradients¨Flight heritage design from CrIS and AHI-8
PrimaryPlatePRTHousing
PrimaryPlateSidePlate/
Heater
Page 17
Radiation Budget Instrument
Visible Calibration Target Provides Reflected Solar Band Calibration Standard
¨VCT provides 6 laser diode sources§ 375, 405, 445, 690, 915, 1470 nm § Radiometric calibration uses 915nm
laser only§ RSR characterization uses all 6
wavelengths sequentially¨Si and InGaAs photodiodes provide
short-term radiance reference¨ESR provides stable absolute
radiance traceable to NIST§ Used monthly to calibrate
photodiodes and SW / Total channels
¨Laser diodes are remotely located, fiber coupled, providing thermal stability of diodes and sphere
Photodiodes
ElectricalSubstitutionRadiometer(ESR)
IntegratingSphereAperture
FiberOpticPortsforLaserIlluminationInput
Page 18
Radiation Budget Instrument
Solar Cal Target Provides Additional Independent Check of SW/Total Calibration
¨SCT contains three protected Spectralon® solar diffusers for on-orbit calibration checks§ Targets are in a cube orientation within a
sealed enclosure, which protects them from solar degradation
§ At least one surface can be maintained in a pristine condition to track and correct for changes in the “daily” surface
§ The 4th face blocks incoming solar radiation and contamination when the SCT not in use
¨SCT mechanism is space-qualified¨Proven Spectralon® solar diffuser material,
also used by ABI, AHI, COMS, and GOSAT programs
CutawayView
SpectralonSurfaces
ProtectiveEnclosure
Page 19
Radiation Budget Instrument
CSM Provides Low-Jitter Cross-Track Scanning of Optical Module
¨Designs leverage heritage motor/ encoder designs
¨Design optimizes OM thermal performance
¨Twist flex design provides redundant OM connections
¨H infinity control optimizes response and provides robustness to external disturbances
¨Heritage bearing system has proven long life on CrIS
ElectronicsandHousing
Motor/BearingAssembly
BEIEncoder(OpticalUnit)
TwistCapsule
TwistCapsuleMount
AlignmentCubeAssembly
MotorMounts
MotorSupportBracket
InterfacetoOpticalModule
Page 20
Radiation Budget Instrument
Azimuth Rotation Module Provides Reliable Bi-Axial Scan Capability
¨Provides azimuth rotation of upper half of instrument § Rate of 0.5-6.0 deg/sec
¨Open-loop stepping system with simple and reliable control process
¨Resolver feedback in telemetry provides confirmation of positioning
¨Leverages many assemblies with flight heritage § Gearbox, resolvers, hybrid
stepper motor, Electronic Control Unit, launch lock
Gray=Stationary(TiedtoSpacecraft)Blue=RotatingWithRBIBenchOrange=Combination
Launch Lock
ECU
Twist Capsules
Actuator
Resolvers
Page 21
Radiation Budget Instrument
¨ Instrument Design Overview§ Instrument Features§ ConOps Overview§ Module Overviews
¨Performance Overview¨Engineering Development Unit Overview
Instrument Overview
Page 22
Radiation Budget Instrument
CERES-Like Point Spread Function (PSF) Provides Important Data Continuity
¨RBI detector shape mimics the CERES precision aperture, and heritage scan rate and time constant provides best PSF match
¨RBI PSF is required to be smaller than CERES, referenced to 95% energy contour§ i.e., over 95% of RBI
energy must be within the CERES 95% energy contour
¨Close match to CERES PSF enhances data continuity
CERES PSF (95% Energy Contour)
Detector IFOV
63.1 Degree / Sec Scan Rate
95.2%ofRBIEnergyFallsWithintheHeritageCERESContour
(Worst-Case)
Page 23
Radiation Budget Instrument
Knowledge of Relative Spectral Response Ensures Accurate Observations
¨VCT detects changes in Relative Spectral Response (RSR) over life allowing corrections to be implemented
¨SCT can also support corrections
VCTMeasuresResponsivityChangesat6Wavelengths,AllowingRSRChangestoBeCorrected
Total
LW
SW
PreliminaryRSRCurvesUse
MeasuredDataFromPrototypeParts
Radiation Budget Instrument
Page 24
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
0 100 200 300 400 500
Repe
atab
ility(W
/m2sr)
TotalChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=3
TotalChannelRepeat.PRD437
0.000
0.500
1.000
1.500
2.000
2.500
0 100 200 300 400 500
UncertaintyW
/(m2sr)
TotalChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=1
TotalChannelUncert.PRD426
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
0 100 200 300 400
Repe
atab
ilityW
/(m2sr)
SWChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=3
SWChannelRepeat.PRD443
0.0000.5001.0001.5002.0002.5003.0003.5004.0004.5005.000
0 100 200 300 400
UncertaintyW
/(m2sr)
SWChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=1
SWChannelUncert.PRD432
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.500
0 50 100 150
Repe
atab
ilityW
/(m2sr)
LWChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=3
LWChannelRepeat.PRD440
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
0 50 100 150
UncertaintyW
/(m2sr)
LWChannelDynamicRangeW/(m2sr)
CalculatedW/(m2sr)K=1LWChannelUncert.PRD429
Radiometric Performance Expected to Meet Requirements
• Radiometricrepeatabilityanduncertaintyareexpectedtomeetrequirements
• AccurateradiancemeasurementsarecriticaltotheERBCDR
Total Total
LW
SW
LW
SW
Repeatability Uncertainty
RequirementCapability
Page 25
Radiation Budget Instrument
RBI Expected to Satisfy Science Requirements
KeyPerformanceRequirements BaselineScienceRequirements PredictedRBICapability
TotalSpectralRange 0.3to100+microns 0.3to100microns
ShortwaveSpectralRange 0.3to5microns 0.3to5microns
LongwaveSpectralRange 5to50+microns 5to50microns
TotalChannelAbsoluteRadiometricUncertainty ≤Larger of0.575W/m2-sror0.5%(k=1) Compliant– SeePrevious Page
ShortwaveChannelAbsoluteRadiometricUncertainty
≤Larger of0.75W/m2-sror1.0%(k=1) Compliant– SeePrevious Page
LongwaveChannelAbsoluteRadiometricUncertainty
≤Larger of0.575W/m2-sror0.5%(k=1) Compliant– SeePrevious Page
TotalChannelRadiometricRepeatability ≤0.2W/m2-sr+0.1%(k=3) Compliant– SeePrevious Page
ShortwaveChannelRadiometricRepeatability ≤0.2W/m2-sr+0.1%(k=3) Compliant– SeePrevious Page
LongwaveChannelRadiometricRepeatability ≤0.2W/m2-sr+0.1%(k=3) Compliant– SeePrevious Page
TotalChannelLinearity ≤1.5W/m2-sr 0.5W/m2-sr
ShortwaveChannelLinearity ≤1.28W/m2-sr 0.43W/m2-sr
LongwaveChannelLinearity ≤0.54W/m2-sr 0.18W/m2-sr
PointSpread Function >95%ofCERES 95.2%ofCERES,WorstCase
Page 26
Radiation Budget Instrument
¨ Instrument Design Overview§ Instrument Features§ ConOps Overview§ Changes Since SRR§ Module Overviews
¨Performance Overview¨Engineering Development Unit Overview
Instrument Overview
Page 27
Radiation Budget Instrument
¨EDU is a pathfinder for calibration§ Design is quite similar to RBI flight design§ Manufacturing processes are validated § Radiometric performance requirements are demonstrated § Calibration approach is demonstrated
¨EDU is a pathfinder for test execution § “Dry Run” of the Flight pre-launch calibration campaign§ Limited environmental tests bring confidence to design robustness
¨EDU TVAC Testing Scheduled for Summer 2017§ Provides first opportunity to correlate end-to-end radiometric model
Engineering Development Unit
Radiation Budget Instrument
Page 28
EDU is a Representation of Flight Design
EDU
StaticARMEnablesFasterBuild
EDUIsNotelectricallyredundant
MultipleAluminumSubstitutionsto
EnableFasterBuildandTest
QualityStandardsAreSpecifictoEDU-TypeBuild
OpticalModulesfailstraylightrequirements
Page 29
Radiation Budget Instrument
Summary
¨RBI design is optimized for its mission¨RBI provides valuable data continuity with CERES¨Operations are highly flexible to support science needs¨Design utilizes heritage sub-assemblies to minimize development
risk and schedule¨Performance expected to meet requirements¨RTM and EDU provide early risk mitigation
Page 30
Radiation Budget Instrument
Back-Up
Radiation Budget Instrument
Page 31
Modular Design Simplifies Integration
ElectronicsUnit(EU)
Cross-TrackScanModule(CSM)
AzimuthRotationModule(ARM)
ThermalMountingFeet
BenchShroud
SolarCalibrationTarget(SCT)
InfraredCalibrationTarget(ICT)
OpticalModule(OM)
VisibleCalibrationTarget(VCT)
ExternalFilterModule
TwistCapsule
LaserDiodeAssembly
ESRElectronics
TwistCapsuleMountingBracket
CSMAssembly
Page 32
Radiation Budget Instrument
Instrument Design Addresses Mission Needs
¨Design features maximize mission performance§ Stable thermal environment§ Comprehensive suite of calibration targets§ High-performance detectors§ Flexible operational strategy§ PSF closely matched to CERES for best data continuity
¨Design uses flight heritage, as able, to reduce development risk
Page 33
Radiation Budget Instrument
Radiation Budget Instrument is Designed to Meet Mission Needs
¨Measures upwelling earth radiance over a wide spectral range § Ultraviolet to far-infrared (100um)§ Continuous cross-track scans
¨Three spectral bands§ Shortwave (SW): reflected solar
energy§ Longwave (LW): emitted earth
energy§ Total: reflected solar plus emitted
thermal energy¨Very precise calibration
§ Extensive ground calibration program establishes radiometric traceability
§ Multiple onboard targets hold calibration over mission life
Electronics Unit
Azimuth Rotation Module
Optical Modules and Calibration
Targets
Cross-track Scan Module
External Filter
