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STEIN (SupraThermal Electrons, Ions & Neutrals). A New Particle Detection Instrument for Space Weather Research with CubeSats. David Glaser Space Physics Research Group Space Sciences Laboratory University of California, Berkeley. Overview. Introduction/Context Instrument Overview
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STEIN (SupraThermal Electrons, Ions & Neutrals) A New Particle Detection Instrument for Space Weather Research with CubeSats David Glaser Space Physics Research Group Space Sciences Laboratory University of California, Berkeley Small Satellites Conference 2009
Overview • Introduction/Context • Instrument Overview • Mechanical Design • Electrical Design • Modes of Operation • Concluding Remarks Small Satellites Conference 2009
Introduction Small Satellites Conference 2009
UCB/SSL • UC 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 Small Satellites Conference 2009
CINEMA Mission CubeSat for Ions, Neutrals, Electrons, and MAgnetic fields PI Robert Lin Mission Built Around a Concept for a New Particle Detector Called STEIN NSF Funded (Awarded Aug.2009) Small Satellites Conference 2009
CINEMA Mission • As Proposed: • 3 Identical 3U CubeSats • 1 NSF Funded • 2 Funded by Kyung Hee Univ., S. Korea • High Inclination LEO • Ecliptic-Normal Spinner • Launch Vehicle – TBD • 2 Science Instruments • Particle Detector • 3-Axis Magnetometer • (Imperial College London) Small Satellites Conference 2009
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 Small Satellites Conference 2009
Comparison with ESAs Electrostatic Analyzer (ESA) ~3 kg ~3 W Power STEIN 0.40 kg 0.55 W Power Small Satellites Conference 2009
STEIN - Scientific Merit • Measures Electrons, Ions, and Energetic Neutral Atoms • Very Low Energy Threshold • High Energy Resolution Cutting Edge Science Small Satellites Conference 2009
Instrument Overview Small Satellites Conference 2009
SSD Detector New Silicon Semiconductor Detector • 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) Small Satellites Conference 2009
STE STEIN STE + = STEIN Electrostatic Deflection STE – SupraThermal Electrons STEIN – SupraThermal Electrons, Ions, and Neutrals Small Satellites Conference 2009
How STEIN Works • Collimator • ± 2000 V Field Separates Electrons, Ions, and Neutrals to ~20 keV • Particle Attenuator (Blocks 99% of Particles) Small Satellites Conference 2009
Instrument Subsystems • Mechanical • Electronics
STEIN Attenuator Overcenter Cam Mechanism Mechanism Heritage from THEMIS Mission Small Satellites Conference 2009
Assembly Attenuator Mechanism is Modular Small Satellites Conference 2009
Electronics Flow Chart C&DHS Instrument Digital Electronics (FPGA) Control High Voltage Power Supply Power 150 V ±2000 V Science Data Detector Signal Processing Electrostatic Deflection ~8 V Bus Voltage Low Voltage Power Supply 5 V Small Satellites Conference 2009
Signal Processing Only ~1 c/s noise Diagram For One Pixel Small Satellites Conference 2009
Modes of Operation Small Satellites Conference 2009
Modes of Operation Small Satellites Conference 2009
Status & Future of STEIN Small Satellites Conference 2009
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 Small Satellites Conference 2009
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. Small Satellites Conference 2009
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 Small Satellites Conference 2009
Back-up slides Small Satellites Conference 2009
STEIN Specifications Small Satellites Conference 2009
Science Objectives *Energetic Neutral Atoms Small Satellites Conference 2009
Modes of Operation Small Satellites Conference 2009
Data Format Small Satellites Conference 2009
Deflection Modes Small Satellites Conference 2009
Magnetic Storms Magnetic Storms and Storm-Time Ring Current Small Satellites Conference 2009
Magnetic Storms STEIN Will Measure the Storm-Time Ring Current Via ENA Imaging Image Credit: SWRI ENA Image of Ring Current NASA IMAGE Mission __ keV ENA map from STE instrument on STEREO (same detector as STEIN) ___ keV Small Satellites Conference 2009
Charged Particles High Latitude Charged Particle Precipitation • In-Situ Measurements of ~4-100 KeV ion • Remotely sense ion precipitation with Energetic Neutral Atoms (ENAs) NASA/GSFC Small Satellites Conference 2009
Electron microburst observed by Korean STSAT-1 Electron Microbursts Electron Microbursts 1 Second Electron Microbursts (0.10 – 0.25 sec) Cause Unknown Small Satellites Conference 2009
Charge Exchange ENERGETIC NEUTRAL ATOM (ENA) ENERGETIC ION Image Credit SWRI A magnetically trapped ion captures an electron from a neutral hydrogen atom... …creating an energetic neutral atom (ENA) that is no longer trapped. Small Satellites Conference 2009
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. Small Satellites Conference 2009
Charged Particles Storm time particle precipitation Oct 13, 2004 Trapped electrons ExB drift Precipitating electrons Korean STSAT-1 - SSL, Berkeley - Small Satellites Conference 2009
Multi-Satellite Science Separation Speed: 1m/min 1 d: 1.4 km 10 d: 14 km 1 m: 42 km 1y: 504 km Spatial or Time Variation “Is it local acceleration?” Small Satellites Conference 2009
Deflection System Design Edge Pixel Center Pixel 20 keV No Signal in Center Pixel Below ~20 keV Simulated Data Small Satellites Conference 2009 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
SSD Detector • Low Capaciance • Thin Window Dead Layer • Passively Cooled • Pulse-Height Detection Electronics • Detector Area: 4 x 0.1 cm2 • Electrons: ~2-40 keV • Ions: ~4-40 keV • Neutrals: ~4-20 keV • Resolution: ~<1 keV FWHM Small Satellites Conference 2009
STEIN Housing Single Piece of Machined Aluminum Small Satellites Conference 2009
Collimator • 60° x 40° Aperture • Baffles • Cu plated BeCu • Blackened Small Satellites Conference 2009
Deflection Plates Copper Epoxied to G10 Ebanol C Surface Treatment Small Satellites Conference 2009
NanoMuscle Actuator • Uses Shape Memory Alloy (SMA) Wire • Stroke: 3 mm • Rated Force: 125 gf Small Satellites Conference 2009
Over-Center Mechanism Over-Center Cam Mechanism Small Satellites Conference 2009
Testing Electronics Box STEIN STEIN with 3-Axis Manipulator Small Satellites Conference 2009
Preliminary Test Results 15 keV Electron Data Counts/Sec, Angle = 0° At > ±300 V All Particles Deflected to One Edge Pixel (Except for Scattering) Small Satellites Conference 2009