Post on 16-Jan-2016
Cosmic dust Reflectron for Isotopic Analysis (CRIA)
Conceptual Design Review
Laura Brower: Project ManagerDrew Turner: Systems EngineerLoren ChangDongwon LeeMarcin PilinskiMostafa SalehiWeichao Tu
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Presentation Overview
• Introduction to Problem – Loren Chang• Previous Dust Analyzers – Loren Chang• LAMA Overview – Marcin Pilinski• Introduction to CRIA – Weichao Tu• Requirements – Drew Turner• Verification – Marcin Pilinski• Risk – Laura Brower• Current Analyses and Trades – Mostafa Salehi• Schedule – Dongwon Lee
Loren Chang3
Space is Dusty!
• Space is filled with particles ranging in size from molecular to roughly 1/10th of a millimeter.
• Dust absorbs EM radiation and reemits in the IR band.
• Dust can have different properties and concentrations, ranging from diffuse interstellar medium dust to dense clouds, and planetary rings.
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Comets, asteroids, and collisions in the new planetary system produce interplanetary dust.
Interstellar dust is believed to be produced by older stars and supernovae, which expel large amounts of oxygen, silicon, carbon, and other metals from their outer layers.
Clouds of dust and gas cool and contract to form the basic building blocks for new stars and planetary systems.
Loren Chang
Heritage
• Past instruments have focused primarily on understanding the flux and chemical composition of cosmic dust.
• Missions have focused on in-situ measurement and
sample return.
CDAAerogel CollectorCIDA SDC
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Student Dust Counter (New Horizons)
• Polyvinylidene fluoride (PVDF) film sensors.
• In-situ measurement of dust flux, mass, and relative velocity.
• Cannot resolve smaller particles (< 10-12 g) nor measure elemental composition.
lasp.colorado.edu/sdc
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Cosmic Dust Analyzer (Galileo, Ulysses, Cassini)
• Incoming dust particles ionized, then accelerated through electric field to detector.
• Time of Flight (TOF) used to infer elemental masses of constituents.
• Parabolic target is difficult to manufacture precisely. Low mass resolution (20-50 m/Δm)
Target
R. Srama et al., The Cosmic Dust Analyzer (Special Issue Cassini, Space Sci. Rev., 114, 1-4, 2004, 465-518)
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Stardust
• Interstellar and interplanetary dust particles trapped in aerogel.
• Direct sample return for analysis of elemental composition on Earth.
• Requires highly specialized mission.
stardust.jpl.nasa.gov
Loren Chang9
Cometary and Interstellar Dust Analyzer(Stardust)
• Uses impact ionization principle similar to CDA, electric field in reflectron is parabolic, eliminating the need for a parabolic target. Improved mass resolution over CDA (250 m/Δm)
• Small target area compared to previous instruments. Roughly
1/20th target area of CDA.
J. Kissel et al., The Cometary and Intersteller Dust Analyzer (Science., 304, 1-4, 2004, 1774-1776)
Marcin Pilinski10
Large Area Mass Analyzer LAMA Concept: Sub-systems
IONIZER
Target
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LAMA Concept: Sub-systems
Ring Electrodes
Annular Grid Electrodes
Target
ANALYZER (Ion Optics)
Grounded Grid
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LAMA Concept: Sub-systemsDETECTOR
Detector
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LAMA Concept: Operationincoming dust particle
Example Dust Composition
Species-1
Species-2
Species-3
Target
Key
Increasing mass
Example Spectrum
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LAMA Concept: Operation
dust passing through annular electrodes
Example Spectrum
dust passing through grounded grid
t0
Data collection from detector started
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LAMA Concept: Operation
dust impacts target and ionizes (trigger- t0)
negative ions and electrons accelerated to target
target material also ionizes
Example Spectrum
t0
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LAMA Concept: Operationpositive ions accelerated towards grounded grid (trigger- t1)
Example Spectrum
t1t0 t1t0
Ions of Species-1, Species-2, Species-3, and Target Material
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LAMA Concept: Operation
Example Spectrum
t1t0
positive focused towards detector
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LAMA Concept: Operation
Species-1 arrives at detector
Example Spectrum
t1t0 t2
positive ions arrive at detector
Ions of the same species arrive at the detector at the same time with some spread
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LAMA Concept: Operationpositive ions arrive at detector
Species-2 arrives at detector
Example Spectrum
t1t0 t2 t3
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LAMA Concept: Operationpositive ions arrive at detector
Species-3 arrives at detector
Example Spectrum
t1t0 t2 t3 t4
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LAMA Concept: Operationpositive ions arrive at detector
Ionized Target Material
Example Spectrum
t1t0 t2 t3 t4 t5
Target material has characteristic peak
Marcin Pilinski22
LAMA is promising, but…
• Several tasks have yet to be completed:
• Dust triggering system not yet implemented.
• No decontamination system.
• System has not yet been designed for or tested in the space environment.
Weichao Tu23
Cosmic dust Reflectron for Isotopic Analysis
(a cria is a baby llama)
Hi, I’m LLAMA
Hi, I’m CRIA.Am I Cute?
Weichao Tu24
CRIA Project Motivation
• LAMA Development– To scale down the LAMA instrument to a size
better suited for inclusion aboard missions of opportunity. Technology Readiness Level (TRL) of LAMA can be further improved from level 4 to level 5
• Mission opportunity– A universal in-situ instrument design is needed for
future mission that can incorporate high performance and large sensitivity and can be adapted to various missions.
Weichao Tu25
CRIA Project Goals
• Mission Goal– Design an instrument capable of performing in-situ measurements of the
elementary and isotopic composition of space-borne dust particles
• Science Goal– Detect dust particles and determine their mass composition and isotopic
ratios
• Engineering Goals– Design an instrument based on the LAMA concept that achieves the
following: reductions in size, mass, and power in order to be compatible with possible missions of opportunity
– Achieve a Technology Readiness Level (TRL) of five or higher for the instrument
– To investigate the limits of scalability of the instrument and determine the upper and lower limits of sensitivity (size: between 50% and 125%) in order to provide statistical data and options for a variety of possible missions
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Baseline Design• Inherited from LAMA concept•Triggering system•Scaling LAMA by a factor of 5/8•Capable of heating the target area for decontamination •Capable of interfacing with a dust trajectory sensor (DTS)•A closed design with a cover
•MCP detector may be changed to a large area detector
Heater
HeaterD
TS
t-1t0t1
t2Cover
Weichao Tu
Baseline Design װ
• Specifications of CRIA and LAMA
Parameter CRIA LAMA
Effective Target Area (m2) >0.045 0.2
Mass Resolution (m/m) >100 (team goal of 200) 200
Diameter (cm) 40 64
Power Consumption (W) <10 >10
Instrument Mass (kg) <10 >10
Previous Instrument ComparisonInstrument
Measurement Type
Instrument TypeParameters Measured
Mass Resolution
Surface Area (m2)
CRIA In-Situ
Time-of-Flight Reflectron
Flat electrode&Target
Flux and Composition
>100 (team goal of 200)
0.13
LAMA In-Situ
Time-of-Flight Reflectron
Flat electrode&Target
Flux and Composition
200 0.32
SDC In-Situ PVDF Flux - 0.125
StardustSample return
Aerogel collector Composition - 0.1
CDA In-SituTime-of-Flight
Parabolic TargetComposition 50 0.1
CIDA In-SituTime-of-Flight
ReflectronComposition 250 0.005
Requirements: Top Level
1.TR1 4 The instrument shall be derived from the LAMA concept
1.TR2 1 The instrument shall measure the mass composition of dust particles with a simulated mass resolution of at least 100 m/Δm [Team goal: 200 m/Δm]. Mass resolution is derived from the full width of the mass peak, m/Δm = t/2Δt, where t is time of flight and Δt is the base peak-width.
1.TR3 3 The instrument shall be capable of mechanically interfacing with a dust trajectory sensor (DTS)
1.TR4 2 The instrument shall be designed to meet the requirements of TRL 5
1.TR5 5 The total project cost shall not exceed $25,000.00
1.TR6 6 The instrument shall be constructed and verified by 1 December 2007
1.TR7 7 Complete design documentation shall be delivered by 1 May 2007
Drew Turner28
Drew Turner30
Requirements Flowdown
Analyzer
Ionizer
Detector
Electronics/CDH
Structural/Mechanical
Thermal
Each includes:
-Functional Reqs
-Performance Reqs
-Design Constraints
-Interface Reqs
Level 1:
Top Level Requirements
Level 2: System Requirements
- Functional Requirements
- Performance Requirements
- Design Constraints
- Interface Requirements
Level 3:
Subsystem Requirements
Drew Turner31
Requirements: Levels 2 and 3
• Functional Reqs: Define system functions; answer “what”, “when”, “where”, and “how many” type questions about the system.
CRIA Example: 2.FR5: The instrument shall be capable of detecting positive and negative ion species.
• Performance Reqs: Define how well system is to perform its various tasks; answer “how well”, “how often”, and “within how long” type questions.
CRIA Example: 2.PR6: The instrument shall be able to record a mass spectrum from Hydrogen to at least m = 300 (amu) and be independent of the triggering method.
Drew Turner32
Requirements: Levels 2 and 3
• Design Constraints: Defines factors that put limits on the system, such as environment and budget.
CRIA Example: 2.DC1: The instrument shall have a closed design such that no light can enter the interior except through the field of view.
• Interface Reqs: Defines system inputs, outputs, and connections to other parts of the system or to some other, external system.
CRIA Example: 2.IR1: The instrument shall provide a mechanical interface for the Dust Trajectory Sensor
(w/ given mass, dimensions and COG).
Marcin Pilinski33
Requirement Verification Resources
ANALYSIS Applicable Req
SimIon analysis of time of flight, effective target area.
TR2, FR2, PR1, PR6
SolidWorks analysis of mass, structural integrity, thermal properties
TR3, FR4, PR4, IR1
TEST
Bell-Jar FR3, FR6, DC3
Thermal-Vacuum PR4
Vibration table TR4
Laura Brower
Solar UVSources
System Level Risk Assessment
Detector damaged
Noise in spectra
Events
Mitigation
Technol. Risk
Risk Level
UV reflective electrodes
On/Off detector
mode
UV impact on detector unknown
High
Mechanical Malfunction
Inaccurate spectra / no
spectra recorded
High
•No risk mitigation
Radiation / Plasma
Electronics malfunction
Instrument charging
Use rad-hard electronics
and rad protect
electronics
Arcing
Medium
•Instrument charging not understood
Micro-meteroid
Target area damaged
Detector damaged
Shielding in annular
electrode design
Medium
•High probability of impacts
Prelaunch Contamination
Contaminated spectra
Aperture Cover
Use clean room
Low
•Common practice
Material Outgassing
Contaminated spectra
Vaporize contaminants with heater
Use low outgassing mt’ls
Low
•Materials known
•Heater temp range can be large
•Technology limits unknown
Current Analyses and Trades
• Arcing Preliminary calculation:- Breakdown electric field as a function of pressure for air- Maximum electric field as a function of gap distance for inner
electrode- Reduced size increases risk of arcing
- Unexplored area: The arcing in the plasma
• Material outgassing- Material selection to low outgassing specification (G-10,
Noryl, ceramic, etc.)- More details on other material properties (thermal
expansion, tensile strength, density, etc.)
Current Analyses and Trades
• Thermal power required- Preliminary calculation on power require to heat target
area to 100 oC is on going- Target design is thermally conductive
• Detector protection against UV and Micrometeoroids
- We calculated micrometeoroid flux at 1 AU- UV reflection / absorption by coating instrument interior - Determine impact of UV on detector performance
Dongwon Lee37
Schedule
Dongwon Lee38
Schedule
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Questions?
Backup Slides
Previous Instrument Comparison
InstrumentMeasurement
TypeInstrument Type
Parameters Measured
Mass Range (g)
Target Area (m2)
SDC In-Situ PVDF Flux > 10-12 0.125
StardustSample return
Aerogel collector Composition - 0.1
CDA In-SituTime-of-Flight
Parabolic TargetComposition 10-16 - 10-10 0.01
CIDA In-SituTime-of-Flight
ReflectronComposition 5 x 10-14 - 10-7 0.005
Mass Resolution (m/m)
• Mass resolution describes the ability of the mass spectrometer to distinguish, detect, and/or record ions with different masses by means of their corresponding TOFs.
• m/m will be affected by:– The energy and angular
spread of emitted ions– Sampling rate
m/m= t/2t CRIA: dt=2ns
– Electronic noise
peak width FWHM
m
m
m
FWHM: full width at half maximum
Arcing
• Electric field required for arcing in a neutral dielectric given by Paschen’s Law. Nonlinear function of pressure and gap distance.
Expected Impacts
For randomly tumbling object. Per NASA Technical Memorandum 4527, p.7-3
Possible Questions
• What is the elemental composition of cosmic dust?
• What is the dust flux and its mass dependence?
• What direction is the dust coming from?
• What are the differences in composition and size between interstellar and interplanetary dust?
Dongwon Lee46
Schedule