THEMIS MISSION CDRESA- 1 UCB, June THEMIS T IME H ISTORY OF E VENTS AND M ACROSCALE I NTERACTIONS DURING S UBSTORMS RESOLVING THE MYSTERY OF WHERE, WHEN AND HOW AURORAL ERUPTIONS START THEMIS Mission Critical Design Review – ESA June 14 – 18, 2004 University of California, Berkeley

THEMIS MISSION CDRESA- 2 UCB, June ESA Plasma Instrument Mission CDR Dr. C. W. Carlson and THEMIS ESA Team UC Berkeley SSL

THEMIS MISSION CDRESA- 3 UCB, June Overview ESA Plasma Instrument Requirements & Specifications Heritage Design Overview Block Diagram Component Descriptions Mechanical Test and Calibration

THEMIS MISSION CDRESA- 4 UCB, June Requirements and Specifications Measurement The ESA instrument measures 3-D electron and ion energy distribution functions over the Energy range 10 eV to 30 keV. Typical energy sweep has 16 or 32 energy samples A full 4-pi distribution measurement is produced during each spin Sweep rate of 32/spin gives dense sample of 3-D particle distributions Raw measurements are compressed to selectable “reduced distributions” and moments Implementation Ion and electron “top-hat” electrostatic analyzers have 180 degree field of view Field of view is divided into 8 electron and 16 ion elevation bins Plasma analyzers have hardware programmed functions: sweep rate, sweep waveform, energy range, data collection rates. These functions are set by command. Higher level data formatting and computed products are carried out in the ETC board. Energy sweep is exponential with programmable starting energy and step ratio

THEMIS MISSION CDRESA- 5 UCB, June Heritage ESA Instrument Design is based on FAST plasma instrument Nearly identical measurement requirements Well proven design – all 16 FAST ESA detectors remain fully functional after 7 years in orbit (Design requirement was 3 years in high radiation environment) Flight hardware designs and calibration facilities can be used with minor changes The only major electronics design change is to upgrade from the ACTEL 1020 gate arrays to the ACTEL RT54SX72S. This reduces the number of components required and makes the design consistent with other THEMIS instruments. THEMIS instrument uses the FAST strategy of “dumb” sensors having hardware defined measurement modes, combined with a “smart” processor-based interface board that performs data formatting and higher level computations. The ETC board provides this intermediate processing for both the ESA and SST.

THEMIS MISSION CDRESA- 6 UCB, June REQUIREMENTESA DESIGN IN-1. The Instrument Payload shall be designed for at least a two-year lifetime Compliance. Lifetime has been considered in all aspects of ESA Design. System design and components are direct copy of FAST ESA (still fully functional after 7 years on orbit) IN-2. The Instrument Payload shall be designed for a total dose environment of 33 card/year (66 krad for 2 year mission, 5mm of Al, RDM 2) Compliance. Common Parts buy for Instrument Payload. Lower radiation dose than FAST ESA has experienced without problem. IN-3. The Instrument Payload shall be Single Event Effect (SEE) tolerant and immune to destructive latch-up Compliance. FAST components were selected for SEE and latch-up immunity and are verified by flight history. IN-7. No component of the Instrument Payload shall exceed the allocated mass budget in THM-SYS-008 THEMIS System Mass Budget.xls Compliance kg Allocated. This allocation will be met. As built mass for the equivalent FAST instrument is 1.92 kg. Radiation Shielding accounts for the additional mass. IN-9. No component of the Instrument Payload shall exceed the power allocated in THM-SYS-009 THEMIS System Power Budget.xls Compliance W Allocated. As built power for equivalent FAST instrument is 1.75 Watt. IN-13. The Instrument Payload shall survive the temperature ranges provided in the ICDs Compliance. ESA is designed and will be tested to comply with the ICD requirements. IN-14. The Instrument Payload shall perform as designed within the temperature ranges provided in the ICDs Compliance. ESA is designed and will be tested to comply with the ICD requirements. Mission Requirements

THEMIS MISSION CDRESA- 7 UCB, June REQUIREMENTESA DESIGN IN-16 The Instrument Payload shall comply with the Magnetics Cleanliness standard described in the THEMIS Magnetics Control Plan Compliance. THM-SYS-002 Magnetics Contamination Control Plan. IN-17 The Instrument Payload shall comply with the THEMIS Electrostatic Cleanliness Plan Compliance. THM-SYS-003 Electrostatic Cleanliness Plan IN-18 The Instrument Payload shall comply with the THEMIS Contamination Control Plan Compliance. THM-SYS-004 Contamination Control Plan IN-19. All Instruments shall comply with all electrical specifications Compliance. THM-IDPU-001 Backplane Specification. IN-20. The Instrument Payload shall be compatible per IDPU-Instrument ICDs Compliance. THM-SYS-105 ESA and SST Electronics Card (ETC) Specification. Verification Matrices to be completed. IN-21. The Instrument Payload shall be compatible per the IDPU-Probe Bus ICD Compliance. THM-SYS-101 IDPU/ESA-to-Probe ICD. Verification Matrices to be completed. IN-23 The Instrument Payload shall verify performance requirements are met per the THEMIS Verification Plan and Environmental Test Spec. Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed. IN-24 The Instrument Payload shall survive and function prior, during and after exposure to the environments described in the THEMIS Verification Plan and Environmental Test Specification Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed. Mission Requirements

THEMIS MISSION CDRESA- 8 UCB, June REQUIREMENTESA DESIGN IN.ESA-1. The ESA shall obtain partial moments of the 3D plasma electron and ion distributions in the magnetotail plasma sheet Compliance. ESA will provide the ETC board with plasma measurement data sufficient for computing the required moments. IN.ESA-2. The ESA shall measure differences in velocity and ion pressure between probes in the magnetotail plasma sheet Compliance. ESA will provide the ETC board with plasma measurement data sufficient for computing the required moments. IN.ESA-3. The ESA shall measure ion and electron distributions that are associated with the current disruption process Compliance. ESA will provide the ETC board with plasma measurement data sufficient for computing the required moments. IN.ESA-4. The ESA shall be capable of measuring ion moments and differences of those moments in the magnetosheath and solar wind. Compliance. ESA will provide the ETC board with plasma measurement data sufficient for computing the required moments. Solar wind moments will be limited to a specific range of velocity and density consistent with instrument saturation. Science Requirements

THEMIS MISSION CDRESA- 9 UCB, June REQUIREMENTESA DESIGN IN.ESA-5. The ESA shall measure ions and electrons over an energy range of 10eV to 30 keV Compliance. Satisfied by design. IN.ESA-6. The ESA energy sampling resolution, dE/E, shall be better than 25% FWHM for ions and electrons Compliance. Satisfied by design. IN.ESA-7. The ESA shall be capable of measuring ion and electron energy flux of 10^4 to 10^9 keV/cm^2/s/Str/keV Compliance. Satisfied by design. IN.ESA-8. The ion ESA geometric factor shall be attenuated in the solar wind to avoid saturation. Compliance. High fluxes of solar wind ions will be accommodated by small area anodes in the equatorial view directions. IN.ESA-9. The ESA shall supply partial energy moments at one spin time resolution. Compliance. Satisfied by design. IN.ESA-10. The ESA shall have a 180 deg. elevation FOV with a minimum angular resolution of 22.5 deg. Compliance. Satisfied by design. IN.ESA-11. To resolve the solar wind, the ESA shall have a FOV with enhanced resolution of ~ 6 deg. Compliance. Satisfied by design. IN.ESA-12. The ESA shall produce measurements of particle distributions over the entire 4pi steradian field of view in one spin period. Compliance. Satisfied by design. IN.ESA-13. ESA calibration shall ensure <20% relative flux uncertainty (not including statistical uncertainty) over the ranges defined above. Compliance. Satisfied by on-orbit calibration of plasma density with wave measurements. Performance Requirements

THEMIS MISSION CDRESA- 10 UCB, June ESA Development Team ESA Systems Definition and Specifications: Charles Carlson Mechanical: Bill Elliott, Paul Turin Analog and Digital Systems: Charles Carlson, Mike Ludlam IDPU Instrument Interface: Robert Abiad Flight Software: Frank Harvey Fabrication and Parts Management: Chris Scholz Thermal: Chris Smith MCP Testing: Mario Marckwordt, Jeff Hull Calibration and Test Facilities: Mario Marckwordt Ground Support Equipment: Jim Lewis Spacecraft Integration & Test Requirements: Bill Elliott ESA Support Functions Probe Interfaces: Ellen Taylor Reliability and Quality Assurance (R&QA): Ron Jackson Parts Engineering: Jorg Fischer

THEMIS MISSION CDRESA- 11 UCB, June Design Overview THEMIS Uses FAST ESA Design (1/2 of a FAST module) Modular for efficient testing, assembly and repair Entrance sealed and nitrogen purged Outstanding operational performance Specifications: 180 degree elevation field of view with a minimum angular resolution of 22.5 degrees. To resolve the solar wind the IESA will have a field of view with enhanced resolution of approximately 5.62 degrees. Pulse Amplifiers Digital Interface & HV Sweep HV Supplies } MCP

THEMIS MISSION CDRESA- 12 UCB, June THEMIS ESA Simplified View of the new THEMIS ESA mechanical design illustrating design changes. Changes from FAST Ion Detector Anode pattern Cover Release Mechanism (SMA Actuator) Upgrade ACTEL Gate Arrays to RT54SX72S HV Supplies repackaged in pairs Higher density ACTELs on Preamp Board and Main Interface Board

THEMIS MISSION CDRESA- 13 UCB, June Block Diagram Electronics functional design is identical to FAST (with ACTEL upgrades) Three circuit modules plug together for efficient assembly and test MCP pulse amplifiers are Amptek A121 with programmable gain All discrete logic, counters, and HV DAC drivers are Actel FPGAs HV & LV supplies are mature designs built at UCB SSL

THEMIS MISSION CDRESA- 14 UCB, June Analyzer/Anode/Preamp FAST ESA module Themis uses FAST module design IESA/EESA Analyzers Analyzer deflection plates Aperture closer mechanism UV rejection Cu-Black coating Nitrogen purge system Anode Boards Mounts MCPs HV Interface connectors HV coupling capacitors Preamp Board AMPTEK A121 preamps Actel logic arrays Anode and Logic board interfaces

THEMIS MISSION CDRESA- 15 UCB, June MCP/Anode Board Assembly Top Bottom Anode boards includes: MCP Mounting Hardware “Spring finger” clamp rings HV electrode connections Nitrogen purge plumbing HV Interface HV Plugs and wiring HV filter capacitors Bias resistor Preamp Interface Limit resistors & clamp diodes Preamp interface connector Materials Polyimide / glass PCB PEEK mounting rings KAPTON spacers Gold plated Be Cu springs 16 Anode 8 Anode

THEMIS MISSION CDRESA- 16 UCB, June MCP Preamp/Accumulator Preamp board includes: 24 AMPTEK A121 hybrid preamps ACTEL Gate array contains: 24 x 14 bit accumulators Command/Data Interface Command interpreter Test pulse generator Preamp gain control DAC driver Commandable selective anode blocking MCP Anode board interface Radiation “spot shielding” for preamps

THEMIS MISSION CDRESA- 17 UCB, June HV Sweep & Digital Interface HV Sweep/ Interface board includes: Main data interface to ETC board and IDPU power board HV fixed and sweep supply control HV Sweep waveform generator (Amptek HV-601 high voltage optocouplers) Housekeeping multiplexer Plug-in interface to anodes and HV supplies Modified FAST Sweep/Interface Board Themis board is about 30 % shorter length

THEMIS MISSION CDRESA- 18 UCB, June FAST HV Supply Assembly FAST HV Interface Board (mounts on back side of Sweep/Interface board) Themis board is about 30 % shorter length HV Assembly board includes: Four HV supplies with interface mother board (FAST example has 6 supplies) Supplies are packaged as a pair of dual supplies. HV supply assembly and Digital interface boards share structural mount plate HV supplies have HV sockets that mate directly with HV plugs on HV sweep board and on anodes.

THEMIS MISSION CDRESA- 19 UCB, June HV Supply and VMI Multiplier A single FAST HV Supply shown with a sample FAST HV multiplier module and the commercial replacement module from VMI (HM402N10). A total of 25 HV supplies on FAST have operated without incident for seven years. The VMI multiplier replaces the SSL fabricated component: Huge saving of in-house technician work VMI part has been tested for use on STEREO The multiplier is physically and electrically compatible with existing FAST design THEMIS Design has a pair of dual HV Supplies 2 Dual THEMIS HV Supplies

THEMIS MISSION CDRESA- 20 UCB, June ESA Instrument Power Supply Low Voltage Converter Direct Copy of FAST Design Regulation and Current Limiting of Primary 28 Volt Input is Provided by IDPU Power Control Board Reference Voltages Generated by Secondary Regulators Power Converter Provides Isolated Grounding for ESA

THEMIS MISSION CDRESA- 21 UCB, June Test and Calibration UCB SSL has automated calibration facilities (FAST, WIND heritage) that will be used for THEMIS ESA calibrations Facility uses cryogenic pumped vacuum chambers with computer controlled ion and electron guns and 3-axis manipulators New Ion Gun Facility will be used for both ESA and SST calibrations (See SST Calibration Presentation) All six ESA units (5 flight/ 1 spare) use identical calibration procedures adapted from FAST Full environmental testing (Thermal / Vacuum, EMC, Vibration) 3 Axis Manipulator Calibration Chamber

THEMIS MISSION CDRESA- 22 UCB, June ESA GSE Block Diagram GSE workstation Bench LVPS GPIB via USB Ethernet GSE software: based on Mike Hashii’s STEREO GSE tools, FAST calibration S/W Ethernet router To lab network, optional external monitoring and commanding 3-axis servo amplifier Manipulator Electron and ion guns HVPS Vacuum chamber PCI motion controller PWR Digital Multimeter Ethernet ESA 6U GSE Interface Board + Nios embedded processor Analog HSK TM Data TM Clock CMD Data CMD Clock CMD Gate

THEMIS MISSION CDRESA- 23 UCB, June ESA GSE Software Capabilities: Scripted or interactive entry of CDI, GPIB, and manipulator commands Simulates ETC board to command ESA and acquire telemetry Real-time display of counter histograms, raw hex telemetry dumps, analog housekeeping values, manipulator status Can act as TCP/IP server for remote monitoring or controlling via MATLAB, IDL, or LabWindows/CVI code Telemetry and log messages archived to disk for later examination and processing Device control GPIB programmable LV and HV power supplies, digital multimeter Internal PCI motion controller, external servo amp and motor drive TCP/IP interface to 6U VME GSE Interface Board for sending CDI commands, acquiring telemetry and analog housekeeping values

THEMIS MISSION CDRESA- 24 UCB, June ESA Mechanical Design

THEMIS MISSION CDRESA- 25 UCB, June ESA Exploded View

THEMIS MISSION CDRESA- 26 UCB, June Circuit Board Mounting Interface Bracket Interface Circuit Board High Voltage Circuit Boards Mother Board

THEMIS MISSION CDRESA- 27 UCB, June ESA Exploded (Close-up) Cover Assembly Aperture Ring Hemisphere Assembly Detector Base Anode Assembly Radiation Shield

THEMIS MISSION CDRESA- 28 UCB, June ESA Anode Assembly

THEMIS MISSION CDRESA- 29 UCB, June Typical ESA Anode Assembly (Exploded) Anode Plenum Ring Plug Regulator Spacer, OD Spacer, ID Dowel Pin, PEEK Micro Channel Plate (MCP) Spring Plate Clamp Spring, Inside Clamp Spring, Outside Spacer, OD Spacer, ID Grid, MCP Clamp Ring, OD Clamp Ring, ID

THEMIS MISSION CDRESA- 30 UCB, June Typical Hemisphere Cross-Section Design Features: Interior Surface of Outer Hemisphere is Serrated & Interior Surfaces of Both Hemispheres are Ebanol (Copper Black) Coated for UV Rejection Exit Grid Isolates the Analyzer Optics from MCP Bias Voltages Both Hemispheres Mounted to Single Structural Plate to Ensure Good Alignment

THEMIS MISSION CDRESA- 31 UCB, June Typical ESA HEMISPHERE Assembly Outer Hemisphere O-Ring Inner Hemisphere Dome Tab Dome Mount Grid, Hemisphere Spider Plate

THEMIS MISSION CDRESA- 32 UCB, June Hemisphere Cover Assembly Hemisphere Cover Cover Gasket Diaphragm Spring Spring Clamp Gasket Clamp

THEMIS MISSION CDRESA- 33 UCB, June Covers Closed Cross-Section

THEMIS MISSION CDRESA- 34 UCB, June Covers Open Cross-Section

THEMIS MISSION CDRESA- 35 UCB, June Cover Release in Cocked (Closed) Position Release Plate Compression Spring Slider, IESA Slider, EESA Release Spring Roller Pin Release Rod Roller Shim Nut Plate, Spring Nut Plate, Slider Chock, Spring Bushing, Linkage Tube, Linkage Link, EESA Link, IESA Bearing Cap Spring Mandrel Ball Bearing Linkage Spacer Nut Plate, Actuator Bushing, Actuator Link Bearing, Linkage Washer, Actuator Link SMA Actuator Tee Bone Link, Actuator Switch Actuator, Switch Nut Plate Spring Block Washer Plate

THEMIS MISSION CDRESA- 36 UCB, June Release Plate Mechanism Cocking Mechanism is cocked externally It is reset-able A “Red Tag” cocking nut may be screwed on the end of the cocking pin to prevent premature actuation of the mechanism. When cocked, there is an external visual indication: the tip of the cocking pin protrudes slightly from the cocking barrel.

THEMIS MISSION CDRESA- 37 UCB, June SMA Actuator & Mechanism Test Results Extensive Testing Vibration Testing Successful 4 minute GEVS test of standard NanoMuscle Successful 4 minute GEVS test of SSL redesigned SMA Actuator (based on NanoMuscle components) Successful 4 minute GEVS test of SMA Actuator and Release Plate Assembly (Did Not Trip Open, Did Open On Command After Vibe Test) Combined ESA + IDPU Final Test in Thermo-Vacuum to be done on all Flight Hardware Cycle Testing Successful completion of three million cycle test of previously Vibration Tested SMA Actuator. Test Each Flight Actuator at instrument operating temps for 1000 Cycles We will be testing Mechanism in July +/- 10 deg operational limits

THEMIS MISSION CDRESA- 38 UCB, June SMA Actuator Margin Analysis SMA Actuator rated at 125 g pull force Force required to pull roller off center (including spring) adjusted to be g Force ratio >3 In addition, we have an additional, redundant SMA Actuator (Pictured Right)

THEMIS MISSION CDRESA- 39 UCB, June Nitrogen Purge & HV Enable Plug NITROGEN PURGE A Nitrogen Line is connected to the ESA Purge Fitting preflight to purge the Interior of the Analyzer. The Nitrogen is supplied at 5 psig and is regulated and filtered in-line at each Anode to supply 1 liter/hour. Purge is accessible on assembled spacecraft. HV ENABLE PLUG Plug is accessible on assembled spacecraft. HV ENABLE PLUG

THEMIS MISSION CDRESA- 40 UCB, June ESA S/C INTERFACE Interface to Spacecraft ESA Mounts To IDPU ESA + IDPU Will Be Installed As a Single Unit ESA Extends Through Corner Panel With 0.100” Clearance all around “Red Tag” Purge Gas Connection and Dust Shield “Green Tag” Purge Gas Cover & HV Enable Plug COCKING PIN PURGE CONNECTOR HV ENABLE PLUG