August 11, 2009 Small Satellites Conference 2009 1 A New Particle Detection Instrument for Space Weather Research with CubeSats David Glaser Space Physics Research Group Space Sciences Laboratory University of California, Berkeley STEIN (SupraThermal Electrons, Ions & Neutrals)
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August 11, 2009 Small Satellites Conference 2009 1 A New Particle Detection Instrument for Space Weather Research with CubeSats David Glaser Space Physics.
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August 11, 2009 Small Satellites Conference 2009 1
A New Particle Detection Instrument for Space Weather
Research with CubeSats
David GlaserSpace Physics Research Group
Space Sciences LaboratoryUniversity of California, Berkeley
STEIN (SupraThermal Electrons, Ions & Neutrals)
August 11, 2009 Small Satellites Conference 2009 2
Overview• Introduction/Context
• Instrument Overview
• Mechanical Design
• Electrical Design
• Modes of Operation
• Concluding Remarks
August 11, 2009 Small Satellites Conference 2009 3
Introduction
August 11, 2009 Small Satellites Conference 2009 4
UCB/SSLUC Berkeley Space Sciences Laboratory•Founded in 1959•Extensive Experience in Space Weather
Research• Sounding Rockets and Balloons• Instruments for >100 NASA Missions• PI for EUVE, CHIPS, FAST, RHESSI &
THEMIS
August 11, 2009 Small Satellites Conference 2009 5
CINEMA Mission
NSF Funded (Awarded Aug.2009)
CubeSat for Ions, Neutrals, Electrons, and MAgnetic fields
PI Robert Lin
Mission Built Around a Concept for a New Particle
Detector Called STEIN
August 11, 2009 Small Satellites Conference 2009 6
CINEMA Mission
As Proposed:•3 Identical 3U CubeSats• 1 NSF Funded• 2 Funded by Kyung Hee Univ.,
August 11, 2009 Small Satellites Conference 2009 7
Particle Detectors in Space
• Used For the Majority of Space Missions
• Need Small, Low Power Instruments, Especially for Multi-Spacecraft Space Physics Missions
NASA/JPL
FAST THEMIS Ulysses
NASA/JPL
August 11, 2009 Small Satellites Conference 2009 8
Comparison with ESAs
STEIN0.40 kg0.55 W Power
Electrostatic Analyzer (ESA)~3 kg~3 W Power
August 11, 2009 Small Satellites Conference 2009 9
STEIN - Scientific Merit
• Measures Electrons, Ions, and Energetic Neutral Atoms
• Very Low Energy Threshold• High Energy Resolution
Cutting Edge Science
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Instrument Overview
August 11, 2009 Small Satellites Conference 2009 11
• Low Energy Threshold (1-2 keV)
• ~1 keV Energy Resolution• Sensitive to Electrons,
Ions, and Neutrals (But Can’t Separate)
• 4 x 1 Pixel Array• Flight Heritage: STEREO
Mission STE Instrument
(SupraThermal Electrons)
SSD DetectorNew Silicon Semiconductor Detector
August 11, 2009 Small Satellites Conference 2009 12
STE STEIN
STE – SupraThermal Electrons
STEIN – SupraThermal Electrons, Ions, and Neutrals
STE + = STEINElectrostatic Deflection
August 11, 2009 Small Satellites Conference 2009 13
How STEIN Works
•Collimator•± 2000 V Field Separates Electrons, Ions, and Neutrals to ~20 keV
•Particle Attenuator
(Blocks 99% of Particles)
Instrument Subsystems
•Mechanical•Electronics
August 11, 2009 Small Satellites Conference 2009 15
STEIN Attenuator
Mechanism Heritage from THEMIS Mission
Overcenter Cam
Mechanism
August 11, 2009 Small Satellites Conference 2009 16
Assembly
Attenuator Mechanism is
Modular
August 11, 2009 Small Satellites Conference 2009 17
Instrument Digital
Electronics(FPGA)
Low Voltage Power Supply
Signal Processing~8 V Bus
Voltage
DetectorElectrostatic
Deflection
150 V±2000 V
5 V
C&DHS
High Voltage Power Supply
Control
Power
Science Data
Electronics Flow Chart
August 11, 2009 Small Satellites Conference 2009 18
Signal Processing
Diagram For One Pixel
Only ~1 c/s noise
August 11, 2009 Small Satellites Conference 2009 19
Modes of Operation
August 11, 2009 Small Satellites Conference 2009 20
Modes of Operation
Mode Description
NormalAll Particle Events Stored and
Downlinked
Decimation~1/N (N = 4,16, 64 etc.) Events
are Downlinked
Attenuation 1% of Particles Reach Detector
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Status & Futureof STEIN
August 11, 2009 Small Satellites Conference 2009 22
Status & Future Plans
• Spring 2009 - Attenuator Mechanism Successfully Tested
• Summer 2009 – Instrument Testing Began
• Fall 2009 - Complete Testing of Prototype
• Fall 2009 - Finalize Flight Design
• Early 2010 - Begin Fabrication of Flight Units
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Final Thoughts
• Small, Low Power Particle Detectors Are Needed.
• STEIN is Small and Low Power.
• STEIN Detects Electrons, Ions, and Neutrals, with Low Energy Threshold and High Energy Resolution.
• STEIN will pave the way for Magnetospheric Constellations with many satellites making multi-point observations.
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Visit us at:
http://ssl.berkeley.edu
For more information:
David Glaser – dglaser(at)ssl.berkeley.edu
Science Questions:
Jasper Halekas – jazzman(at)ssl.berkeley.edu
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Back-up slides
August 11, 2009 Small Satellites Conference 2009 26
STEIN Specifications
Electrons ~2-100 keV
Ions & Neutrals ~4-100 keV
Energy Resolution ~ 1 keV
Count Rate Up to 30,000/sec
Mass ~400 g
Volume Envelope ~650 cm3
Power Consumption ~550 mW
August 11, 2009 Small Satellites Conference 2009 27
Science Objective Measurement
Magnetic Storms & Storm-Time Ring
CurrentENA* Line-of-Sight
Charged Particle Precipitation
Electrons, Ions in-situ
Electron Microbursts Electrons in-situ
Science Objectives
*Energetic Neutral Atoms
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Modes of OperationScientific
Observation
Expected Flux @ ~10 keV
(cm2 s sr keV)-
1
Mode (Electronic
Mechanical)
Avg. Counts/Sec
Ring Current ENAs
~103 *Normal Open
300
Low Altitude ENAs
~104 *Normal Open
3000
Auroral Protons ~105 **Normal Closed
30
Microburst Electrons
~106 † Normal Closed
300
Auroral Electrons ~108**Decimation
Closed
~30,000(before
decimation)
August 11, 2009 Small Satellites Conference 2009 29
Data Format
Data Type No. Bits Resolution
Particle Energy
8 ~0.4 keV
Pixel ID 2 -
Time Stamp
6 ~15 ms
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Deflection Modes
Mode Description
Sweep-2000 V to – 600, 0 V, +600 V
to +2000 V(sweep in < 1 sec)
ENA Mode Hold at ±2000 V
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Magnetic Storms
Magnetic Storms and Storm-Time Ring Current
August 11, 2009 Small Satellites Conference 2009 32
Magnetic StormsSTEIN Will Measure the Storm-Time Ring Current Via ENA Imaging
Image Credit: SWRI
ENA Image of Ring CurrentNASA IMAGE Mission__ keV
ENA map from STE instrument on STEREO (same detector as STEIN) ___ keV
August 11, 2009 Small Satellites Conference 2009 33
Charged ParticlesHigh Latitude Charged Particle Precipitation
NASA/GSFC
• In-Situ Measurements of ~4-100 KeV ion
• Remotely sense ion precipitation with Energetic Neutral Atoms (ENAs)
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Electron microburst observed by Korean STSAT-1
1 SecondElectron Microbursts
Electron Microbursts (0.10 – 0.25 sec)
Cause Unknown
Electron Microbursts
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A magnetically trapped ion capturesan electron from a neutral
hydrogen atom...
…creating an energetic neutral atom(ENA) that is no longer
trapped.
ENERGETICION
ENERGETICNEUTRAL
ATOM(ENA)
Charge Exchange
Image Credit SWRI
August 11, 2009 Small Satellites Conference 2009 36
STE ENA Map
Angular distribution as a function of source direction centered at noon (left) and midnight (right ) on Nov. 6, 2006. STE downstream sensors looked in the magnetotail direction close to midnight and detected larger fluxes than upstream sensors looking towards the Earth (the Earth’s horizon is indicated by red curve). The blue curves show the iso-pitch-angle contours of the local magnetic field. The black curves show the magnetic field lines at dusk, midnight and dawn.
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Storm time particle precipitation
- SSL, Berkeley -
Precipitating electrons
ExB drift
Oct 13, 2004
Trapped electrons
Korean STSAT-1
Charged Particles
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Spatial or Time Variation “Is it local acceleration?”
Separation Speed: 1m/min
1 d: 1.4 km
10 d: 14 km
1 m: 42 km
1y: 504 km
Multi-Satellite Science
August 11, 2009 Small Satellites Conference 2009 39
Deflection System Design
•Sweeping Voltage Selects for Different Particle Energies
•Plate Size and Gap Selected to Balance Deflection and Sensitivity
•Present Design Separates Charged Particles from Neutrals up to ~20 keV
No Signal in Center Pixel Below ~20 keV
Edge Pixel
Center Pixel
20 keV
Simulated Data
August 11, 2009 Small Satellites Conference 2009 40
SSD Detector•Low Capaciance•Thin Window Dead Layer•Passively Cooled•Pulse-Height Detection Electronics