Particles and Fields Package (PFP) Instrument Preliminary Design Review SWEA

1. Particles and Fields Package (PFP) Instrument Preliminary Design Review SWEA David L. Mitchell Paul Turin Ellen Taylor (with many contributions from CESR)

2. CESR / UCB-SSL Collaboration SSL, Berkeley • Pedestal • Digital / FPGA • LVPS (same as for STEREO SWEA) CESR, Toulouse • Analyzer • MCP • Anode • HVPS

3. SWEA Team – SSL • David L. Mitchell (Instrument Lead) • Paul Turin (Mechanical) • Ellen Taylor (Electrical) • Chris Smith (Thermal) • with support from John Hawk at NASA-GSFC • Dorothy Gordon (FPGA) • Peter Harvey (FSW [PFDPU]) • Peter Berg, Selda Heavner (Power Supplies) • Tim Quinn (GSE) • Steve Marker (Facilities) • Kate Harps, Jim Keenan, Misty Willer (Purchasing, Contracts)

4. Christian Mazelle (Lead CoI) Jean-Jacques Thocaven (PM, Electronics) Jean-André Sauvaud, Dominique Toublanc (CoIs) Andrei Fedorov (Detector simulations, Calibrations) Jean Rouzaud (Mechanics, Environmental tests) Claude Aoustin (CESR Technical Manager) Philippe Rouger (Electronics) Eric Lecomte (Integration, Coating) Qiu Mei Lee (Documentation) David Moirin BTS Industrie (Quality Assurance) Marc Bouyé OMP (Thermal) CNES can bring expertise on request (components, EMC…) SWEA Team – CESR

5. SWEA Documentation • Performance Requirements • MAVEN-PM-RQMT-0005, Mission Requirements (Level 2) • MAVEN-PFIS-RQMT-0016, PFP Requirements (Level 3) • MAVEN-PF-SWEA-002, SWEA Specification (Level 4) • Differences from STEREO SWEA • SWEA_STEREOtoMAVENChanges • Interface Documents • MAVEN-PF-SWEA-001I_CESRtoSSLICD (analyzer to pedestal) • MAV-SWE-ICD-001 SWEA MICD (pedestal to spacecraft) • MAVEN_PF_SYS_0xx, PFP interfaces and specifications • Environments • MAVEN-SYS-RQMT-0010 (Environmental Requirements Document) • MAVEN_ESC_specification (electrostatic cleanliness) • Software • MAVEN_PF_FSW_002 • MAVEN_PF_SWEA_012A_FPGA_Specification (Level 5)

6. SWEA Peer Reviews • Analyzer/Front-end peer review at CESR, February 3-4 • Actions and responses discussed in this presentation: • Analyzer, Front-end Electronics (Mitchell, Turin) • Actions and responses discussed in other presentations: • Thermal (Smith) • Digital/LVPS peer review at UCB/SSL, May 10-12 • Actions and responses discussed in other presentations: • Digital/FPGA (Taylor, Gordon) • Power Converter (Berg) • Flight Software (Harvey)

7. SWEA Science David L. Mitchell June 15, 2010

8. MAVEN Level 1 Requirements

9. SWEA Science Goals • Magnetic Topology & Plasma Regime • Crustal Magnetospheres/Cusps • Draped Field Lines o o o

10. SWEA Science Goals MGS MAG/ER • Electron Impact Ionization • Magnetic Pileup Region • Ionosphere

11. SWEA Science Goals Mars Express Shadow 2.35 RM Photo-ionization of CO2by solar h @ 304 Å ESCAPE PEB h-electrons MPB 5 4 3 R (MSO) 2 1 0 Escape associated with heavy ions (M> 16) -3 -2 -1 0 1 2 X (MSO)

12. PF Level 3 Requirements

13. SWEA Data Products FPGA provides a single science data product to the PFDPU Counts per accumulation interval for each of the 16 anodes (as a function of analyzer and deflector sweeps) Complete measurement sequence takes 2 seconds. PFDPU computes three data products, with cadence depending on altitude

14. SWEA Resources

15. Spacecraft Accomodation • Boom location: • Separation from s/c potentials • Large, clear field of view • Sensor head in shadow • Electronics box in sunlight FOV: 360o x ±65o SWEA axis parallel to SC Z when deployed

16. Hardware Implementation: Baseline STEREO SWEA Design

17. CESR and SSL have a long history of successful hardware collaboration: ISEE, GIOTTO, WIND 3D-P, MGS, CLUSTER-CIS, STEREO Instrument lifetimes greatly exceed requirements: WIND, MGS (9 years instead of 2),  CLUSTER-CIS (10 years of operation soon) SWEA Heritage • SWEA design already flying on STEREO • Engineering model available at CESR for tests • Calibration facility available at CESR • Most of STEREO technical team expertise available • STEREO SWEA data analysis team feedback • All tools available for MAVEN SWEA instrument fabrication • Same companies will be in charge of MAVEN instrument fabrication (electronics, mechanics, environmental tests) • AIT compatibility with Planetary Protection under evaluation. • Staff has followed ExoMars PP course (class 4 PP project) • MAVEN SWEA fully funded by CNES until 2016

18. Instrument Geometry

19. Geometric Factor Factor ~4 less Real less than ideal because of actual grid transparencies (interference between two entrance grids), MCP efficiencies, and grid support shadow. SWEA sensitivity appropriate for Mars environment.

20. Dynamic Range (RFA-08) • 10 years of MGS electron data (including solar max and several extreme events) provides basis for needed dynamic range. • Expected count rates of STEREO SWEA at Mars approach saturation only during the most extreme events observed by MGS. • Resolution: Utilize SWEA’s V0 capability to reduce geometric factor by ~50% for energies below 50 eV. Provides additional head room for extreme events.

21. of the sensor at low energy can be controlled by varying the voltage bias U0 between the internal and external grids: where is the energy resolution for zero bias (0.175) and is the incident energy of the electron Thus to increase the energy resolution about 2 times, we apply Variation of Energy Resolution

22. Validation using MEX Measurements (1)

23. Validation using MEX Measurements (2) Simulated Count Rate Reduction of count rates with increase of energy resolution

24. Deflector Positions (RFA-05) STEREO SWEA response function not sufficiently flat as a function of deflection potential Simulations performed to optimize the deflector positions Upper Deflector (UD) Lower Deflector (LD)

25. Deflector Positions (RFA-05) Simulations performed to optimize the deflector positions Key ● STEREO SWEA ● UD + 1 mm, LD - 0.3 mm ● UD + 1 mm, LD - 0.6 mm • Collimation by deflectors eliminated • Max energy for full deflection reduced from 2.4 keV to 1.6 keV

26. Inner Hemisphere Scalloping (RFA-07) RFA-07: Determine optimal scalloping for analyzer inner hemisphere to minimize electron forward scattering which results in a low energy tail to the instrument response function Simulations performed to evaluate different scalloping options None None Round Round Tooth Round Tooth Tooth • Round scalloping on both hemispheres gives the best response, improving secondary electron suppression by a factor of 3.

27. SWEA Electrical Ellen Taylor June 15, 2010

28. SWEA Electrical Block Diagram CESR UCB

29. SWEA Electrical Requirements MAVEN-PF-SWEA-002 SWEA Instrument Specification Functional and Performance Requirements Resource Allocations (board size, power budget) Environmental Requirements (thermal, vibration, radiation) MAVEN-PF-QA-002C UCB Mission Assurance Implementation Plan Parts Level Burn-In Derating MAVEN-PF-SYS-003C Power Converter Requirements Power voltages, current, ripple, transients MAVEN-SWEA-012A FPGA Specification PFDPU CLK/TLM/CMD Interface HV Enable (RAW and MCP) and DAC Control (Sweep and Fixed) Operational Heater Control Pre-amp Input, Test Pulser Output Housekeeping and Memory (external SRAM) I/F

30. SWEA Digital Board Interfaces MAVEN-PF-SWEA-001I CESR to SSL ICD Preamp Pulse Characteristics Test Pulser Frequencies HV Enable and Converter Synch DAC Control Voltages Sweep Waveforms Analog Housekeeping Connector Pin-out MAVEN-PF-SYS-004B PFDPU ICD PFDPU Serial I/F description (CMD/CLK/DATA) Power Interface (28V/RTN) MAVEN-PF-SYS-013E Harness Connector Pin-outs MAVEN-PF-SYS-003C Power Req. Power I/F (voltages, current, characteristics) MAV-RQ-09-0015 Particle and Fields to Spacecraft ICD Heater, Thermister and Cover Actuator Interface

31. Heritage and Design Similarities MAVEN SWEA digital board has direct heritage from STEREO SWEA: Minor interface changes (separate connector to SC for temp sensor, heater and actuator, external PFDPU connector) Changed interface logic to 3.3V from 5V (added translators 54ACT244 on FPGA outputs, UT54ACS164245SEI on pre-amp inputs to FPGA) Minor FPGA part change (RT54SX72S from RT54SX32S) Removed STE digital circuitry and interface Removed latch-up circuitry Minor part changes due to obsolescence, desire to have common parts buy and circuitry MAVEN SWEA digital board is very similar to MAVEN SWIA and STATIC: FPGA and SRAM same as SWIA, different than STATIC Housekeeping (HK MUX and ADC parts) same Fixed and Sweep DACs same minus offset DACs need for STATIC

32. Digital Board Design Command/Data Interface to PFDPU Accumulate counts from each of the 16 anodes Bin data for transfer to PFDPU Enable HVPS and MCP high voltage Control voltage sweeps for analyzer inner hemisphere and deflectors Provide programmable threshold for anode pulse amplifiers SRAM for storing lookup tables and accumulators Generate test pulses Control ADC and MUX to read instrument housekeeping monitors Note: Digital board does not control heaters (S/C) or cover actuators (S/C)

33. FPGA Block Diagram

34. SWEA and SWIA FPGA Similarities Commonalities Both require anode counting frontends Both implement Command & Telemetry Interfaces (CDI functionality for receiving commands and sending messages) Housekeeping Control and Message Format Memory Control Fixed and Sweep DAC Control Timing Backbone (reconfigured to accommodate the different accumulation intervals) Lookup table memory and control (Loader and Checksummer) High Voltage turn-on is a protected command Overcurrent Protection (shown in SWEA block diagram) to be implemented identically in both FPGAs Differences SWIA: 24 Anodes (14 WFOV and 10 NFOV) SWEA: 16 Anodes SWIA: 4 second cycle with 2304 Accumulation Intervals SWEA: 2 second cycle with 488 Accumulation Intervals SWIA Implements Products SWEA Includes Operational Heater Control

35. Electronic Parts SWEA Active Parts List from MAVEN-PF-QA-003K Common Buy Parts • STATUS: • In process of working parts list with GSFC • Blue highlighted parts are commercial, no direct knowledge of heritage • Replacement parts identified • Space study complete, layouts started

36. SWEA Mechanical Paul Turin June 15, 2010

37. SWEA Assembly CESR supplied detector and MCP assembly UCB supplied electronics and mounting interface

38. Stowed on S/C Caged to forward deck up to 20kg balance mass

39. Deployed on S/C SWEA axis parallel to SC Z when deployed (balance mass not shown) FOV

40. SWEA Analyzer • Analyzer section very similar to STATIC and SWIA: • Concentric Hemispheres, Deflectors, one-shot Aperture Cover • Uses TiNi Aerospace P5-403 SMA actuator for Cover release • Inner and outer grids covering aperture • T0 purge • No attenuator

41. Pedestal Exploded View SWEA analyzer Purge port (fitting TBD) LVPS Pedestal housing Digital board Board mounted SC harness and enable connectors Cover HV enable plug

42. Baseplate Mounting holes (4) Area possibly needed for solar absorber Vent port (screened for EMC) HV Enable plug (green tag item) SC harness connector

43. Differences from STEREO SWEA • Modifications to STEREO SWEA analyzer • Deflectors moved slightly to improve response – 1mm up, .3mm down. Resulting FOV blockage fix in process (trim a housing corner). • Exposed surface finishes will be changed to deal with thruster and deep-dip heating (more in thermal section). • Modification of STEREO SWEA pedestal design • STE instrument and supporting electronics removed -- only LVPS and digital board • ½ height, simpler mounting to boom at pedestal periphery • Simpler electrical and mechanical interfaces

44. Structural Analysis - Analyzer As discussed in the Systems presentation, the SWEA analyzer was designed for 30g limit load and 14.7grms random qual level (MAVEN: 66g and 23.1grms). Suitability of the design will be determined after the 1st CLA results are in. Analysis results from STEREO:

45. Structural Analysis - Pedestal • Pedestal: • Worst-case margins for MAVEN MAC and Random loads: Lowest 1st mode frequency = 198Hz

46. SWEA to S/C MICD

47. SWEA to Pedestal MICD

48. SWEA Peer Review Actions A separate peer review was held Feb 3,4 2010 in Toulouse, France. All actions are closed.

49. Contents AIT: CESR Team Facilities Main subcontractors Documentation Cleanliness & contamination issues AIT flow chart CESR Assembly, Integration, and Test

50. AIT Staff • Mechanics: J Rouzaud (G Peyre – Comat) • Integration, coatings, gluing, HV optocouplers : E Lecomte • Electronics, boards integration & tests: JJ Thocaven, P Rouger • Calibrations: A Fedorov, P Rouger, C Mazelle • Procedures, anomalies, QA: D Moirin (BTS) • Harnesses, boards assembling: Microtec • Environmental tests : P Rouger + Microtec