August 11, 2009 Small Satellites Conference 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)

August 11, 2009 Small Satellites Conference Overview Introduction/Context Instrument Overview Mechanical Design Electrical Design Modes of Operation Concluding Remarks

August 11, 2009 Small Satellites Conference Introduction

August 11, 2009 Small Satellites Conference 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

August 11, 2009 Small Satellites Conference 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 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)

August 11, 2009 Small Satellites Conference 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 Comparison with ESAs STEIN 0.40 kg 0.55 W Power Electrostatic Analyzer (ESA) ~3 kg ~3 W Power

August 11, 2009 Small Satellites Conference STEIN - Scientific Merit Measures Electrons, Ions, and Energetic Neutral Atoms Very Low Energy Threshold High Energy Resolution Cutting Edge Science

August 11, 2009 Small Satellites Conference Instrument Overview

August 11, 2009 Small Satellites Conference 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 Detector New Silicon Semiconductor Detector

August 11, 2009 Small Satellites Conference STE STEIN STE – SupraThermal Electrons STEIN – SupraThermal Electrons, Ions, and Neutrals STE + = STEIN Electrostatic Deflection

August 11, 2009 Small Satellites Conference 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 STEIN Attenuator Mechanism Heritage from THEMIS Mission Overcenter Cam Mechanism

August 11, 2009 Small Satellites Conference Assembly Attenuator Mechanism is Modular

August 11, 2009 Small Satellites Conference Instrument Digital Electronics (FPGA) Low Voltage Power Supply Signal Processing ~8 V Bus Voltage Detector Electrostatic 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 Signal Processing Diagram For One Pixel Only ~1 c/s noise

August 11, 2009 Small Satellites Conference Modes of Operation

August 11, 2009 Small Satellites Conference Modes of Operation ModeDescription Normal All Particle Events Stored and Downlinked Decimation ~1/N (N = 4,16, 64 etc.) Events are Downlinked Attenuation1% of Particles Reach Detector

August 11, 2009 Small Satellites Conference Status & Future of STEIN

August 11, 2009 Small Satellites Conference Status & Future Plans Spring Attenuator Mechanism Successfully Tested Summer 2009 – Instrument Testing Began Fall Complete Testing of Prototype Fall Finalize Flight Design Early Begin Fabrication of Flight Units

August 11, 2009 Small Satellites Conference 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.

August 11, 2009 Small Satellites Conference Visit us at: For more information: David Glaser – dglaser(at)ssl.berkeley.edu Science Questions: Jasper Halekas – jazzman(at)ssl.berkeley.edu

August 11, 2009 Small Satellites Conference Back-up slides

August 11, 2009 Small Satellites Conference STEIN Specifications Electrons~2-100 keV Ions & Neutrals~4-100 keV Energy Resolution~ 1 keV Count RateUp to 30,000/sec Mass~400 g Volume Envelope~650 cm 3 Power Consumption~550 mW

August 11, 2009 Small Satellites Conference Science ObjectiveMeasurement Magnetic Storms & Storm-Time Ring Current ENA* Line-of-Sight Charged Particle Precipitation Electrons, Ions in-situ Electron MicroburstsElectrons in-situ Science Objectives *Energetic Neutral Atoms

August 11, 2009 Small Satellites Conference Modes of Operation Scientific Observation Expected ~10 keV (cm 2 s sr keV) - 1 Mode (Electronic Mechanical) Avg. Counts/Sec Ring Current ENAs ~10 3 * Normal Open 300 Low Altitude ENAs ~10 4 * Normal Open 3000 Auroral Protons~10 5 ** Normal Closed 30 Microburst Electrons ~10 6 † Normal Closed 300 Auroral Electrons~10 8 ** Decimation Closed ~30,000 (before decimation)

August 11, 2009 Small Satellites Conference Data Format Data TypeNo. BitsResolution Particle Energy 8~0.4 keV Pixel ID2- Time Stamp 6~15 ms

August 11, 2009 Small Satellites Conference Deflection Modes ModeDescription Sweep V to – 600, 0 V, +600 V to V (sweep in < 1 sec) ENA ModeHold at ±2000 V

August 11, 2009 Small Satellites Conference Magnetic Storms Magnetic Storms and Storm-Time Ring Current

August 11, 2009 Small Satellites Conference 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

August 11, 2009 Small Satellites Conference Charged Particles High Latitude Charged Particle Precipitation NASA/GSFC In-Situ Measurements of ~4-100 KeV ion Remotely sense ion precipitation with Energetic Neutral Atoms (ENAs)

August 11, 2009 Small Satellites Conference Electron microburst observed by Korean STSAT-1 1 Second Electron Microbursts Electron Microbursts (0.10 – 0.25 sec) Cause Unknown Electron Microbursts

August 11, 2009 Small Satellites Conference A magnetically trapped ion captures an electron from a neutral hydrogen atom... …creating an energetic neutral atom (ENA) that is no longer trapped. ENERGETIC ION ENERGETIC NEUTRAL ATOM (ENA) Charge Exchange Image Credit SWRI

August 11, 2009 Small Satellites Conference STE ENA Map Angular distribution as a function of source direction centered at noon (left) and midnight (right ) on Nov. 6, 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.

August 11, 2009 Small Satellites Conference Storm time particle precipitation - SSL, Berkeley - Precipitating electrons ExB drift Oct 13, 2004 Trapped electrons Korean STSAT-1 Charged Particles

August 11, 2009 Small Satellites Conference 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 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 SSD Detector Low Capaciance Thin Window Dead Layer Passively Cooled Pulse-Height Detection Electronics Detector Area: 4 x 0.1 cm 2 Electrons: ~2-40 keV Ions: ~4-40 keV Neutrals: ~4-20 keV Resolution: ~<1 keV FWHM

August 11, 2009 Small Satellites Conference STEIN Housing Single Piece of Machined Aluminum

August 11, 2009 Small Satellites Conference Collimator 60° x 40° Aperture Baffles Cu plated BeCu Blackened

August 11, 2009 Small Satellites Conference Deflection Plates Copper Epoxied to G10 Ebanol C Surface Treatment

August 11, 2009 Small Satellites Conference Uses Shape Memory Alloy (SMA) Wire Stroke: 3 mm Rated Force: 125 gf NanoMuscle Actuator

August 11, 2009 Small Satellites Conference Over-Center Mechanism Over-Center Cam Mechanism

August 11, 2009 Small Satellites Conference Testing STEIN with 3-Axis Manipulator STEIN Electronics Box

August 11, 2009 Small Satellites Conference Preliminary Test Results ED VoltageEdge 1 (+ V) Center 2Center 3Center 4 (- V) ± ≤ 20 ± ≤ 20 ± ≤ 20 ± ≤ 20 ± ≤ 20 ± ≤ At > ±300 V All Particles Deflected to One Edge Pixel (Except for Scattering) 15 keV Electron Data Counts/Sec, Angle = 0°