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