RBSP Science and EFW Instrument Overview

1. RBSP Science and EFW Instrument Overview John Bonnell UC Berkeley jbonnell@ssl.berkeley.edu

2. RBSP EFW SOC-CDRAgenda How did we get here? RBSP Mission and EFW Instrument Review History. What are we talking about? Radiation Belt Storm Probes (RBSP) Mission Science Electric Fields and Waves (EFW) Instrument Design Overview EFW Science Operations Center (SOC): Overview Command, Telemetry, and Ground Support Science Data Center Development Schedule Utilization (INT, Commissioning, Ops) Risks, Status, and Summary What’s it all look like right now? UCB SSL Tour, including hardware and other relevant locales.

3. Review History RBSP Start of Phase A Oct 2006 RBSP Mission Concept Review 30-31 January 2007 RBSP Requirements & Mission Definition Review 2-4 October 2007 RBSP/EFW Preliminary Design Review (w/ SOC) 3-4 September 2008 RBSP Mission Preliminary Design Review 14-16 October 2008 RBSP/EFW Peer Reviews AXB, SPB, IDPU Chassis 28 July 2009 PRE, BEB, DCB, LVPS: electronics, backplane, harness 2 September 2009 DCB FPGA, DCB FSW 3 September 2009 DFB, DFB FPGA 10 September 2009 RBSP/EFW Instrument Critical Design Review 30 September 2009 RBSP Mission Critical Design Review 1-3 December 2009 RBSP/EFW SOC Critical Design Review 26 January 2010 (TODAY) RBSP Launch 18 May 2012 (NET)

4. SOC-CDR Entrance Criteria A successful INST-SOC-PDR: Responses to RFAs in hand, and tendered into PIMS (JAN 2010). ICDR technical documentation: Documents updated to required level (typ. BASELINE, from PRELIMINARY): Instrument and SOC requirements: 7417-9096-05_EFW-UCB Instrument Performance Assurance Matrix RBSP_EFW_SYS_001J_Requirements RBSP_EFW_SYS_010B_SOC_Requirements SOC SW Development Plan: RBSP_EFW_SW_001_SOC_SDP Command and Telemetry database: RBSP_EFW_FSW_005_CTM SOC SW Integration, Test, Verification & Validation plan: SW-005-SOC-001 Updated risk assessment/mitigation (informal). Input provided to Mission-level SOC documents: Science Data Management Plan (SDMP).

5. SOC-CDR Expectations Initial SOC CSCI development has proceeded well. CTG is very mature, and has supported board- and instrument-level testing since Q2 2009. SDC-NRT is through initial development, and in use for instrument level testing since Aug 2009. Documentation and Plans are in place for remainder of EFW SOC. No major open issues EFW is ready to continue with development of SOC infrastructure in support of Instrument- and SC-level Integration and Test (INT), as well as on-orbit instrument support.

6. RBSP Level-1 Mission ScienceEFW Measurement Requirements Provide understanding, ideally to the point of predictability, of how populations of relativistic electrons and penetrating ions in space form or change in response to variable input from the Sun. Which physical processes enhance the radiation belts? What are the dominant processes for relativistic electron loss? How does the ring current and other geomagnetic processes affect radiation belt behavior? The EFW instrument measures the DC and low-frequency electric fields, plasma density structures, and EM waves responsible for the acceleration, loss, and transport of energetic charged particles in the inner magnetosphere.

7. EFW Measurements in Support ofLevel-1 Science Objectives (in detail) The RBSP mission will determine local steady and impulsive electric and magnetic fields …These products will enable the the scientific goals of determining convective and impulsive flows, determining properties of shock generated shock fronts… The RBSP mission will derive and determine spatial and temporal variations of electrostatic and electromagnetic field amplitudes, frequency, intensity, propagation direction, spatial distribution and temporal evolution with sufficient fidelity to calculate wave energy, polarization, saturation levels, coherence, wave normal angle, phase velocity, and wave number for a) VLF and ELF waves, and b) random, ULF, and quasi-periodic electromagnetic fluctuations. These products will enable the scientific goals of determining the types and characteristics of plasma waves causing particle energization and loss including wave growth rates; quantifying adiabatic and non-adiabatic mechanisms of energization and loss........; determining conditions that control the production and propagation of waves High time resolution burst electric and magnetic field measurements will provide understanding of the role in the prompt acceleration and loss of energetic particles of non-linear interactions with discrete large amplitude wave structures.

8. The RBSP Mission Venue:The Inner Magnetosphere Mechanisms associated with energetic particle acceleration and transport (B. Mauk/APL)

9. Level-1 Science and Measurement Objectives (1) • Science Objective: Measure electric fields associated with a variety of mechanisms “causing particle energization and scattering” in the inner magnetosphere. • These mechanisms include: • Energization by the large-scale “steady state and storm time convection E-field” . • Energization by substorm “transient fronts”propagating in from the tail. • “Radial diffusion of energetic particles” mediated by “ULF waves”. • Transport and energization by interplanetary “shock generated transient fronts.” • Adiabatic and non-adiabatic energization by “electromagnetic and electrostatic” waves and (“random”) structures .

10. CRRES measurements of the E-field during a pass through the inner magnetosphere: interplanetary shock induced electric field, large scale MHD waves, and enhancement in convection electric field. E-Fields in the Active Radiation Belt MHD waves: an important mechanism for radially diffusing and energizing particles. The shock induced magnetosonic wave created a 5 order of magnitude increase in 13 MeV electron fluxes in <100 seconds resulting in a new radiation belt that lasted two years The large scale electric field produced a ~70 kV potential drop between L=2 & L-4 and injected ring current plasma. dDst/dt= - 40 nT/hr

11. RBSP EFW InstrumentOn-Orbit Configuration Axial Booms (1 of 2; 12-14-m tip-to-tip) Spin Plane Booms (1 of 4; 80- and 100-m tip-to-tip) IDPU (inside S/C bus, on side panel)

12. EFW Instrument Overview +Z • “A High-Impedance, Low-Noise, Three-Axis Digital Voltmeter in Space” • Booms and Sensors: • Four spin plane booms (2 x 40 m and 2x 50 m) • Two spin axis stacer booms (2x6 to 7 m; length trimable on-orbit) • Spherical sensors and preamplifiers near outboard tip of boom (400-kHz response) • Flexible boom cable to power sensor electronics & return signals back to SC • Sensors are current biased by instrument command to optimize DC and AC response. 2 Instrument Data Processing Unit (IDPU): Main electronic box, controlling sensor bias, A-D conversion, digital filtering, burst memory, diagnostics, mode commanding, TM formatting ). Provides analog interface between EFW and EMFISIS instruments (shared E- and B-field measurement capabilities). 5 4 3 6 Not to Scale 1

13. EFW Instrument Block Diagram

14. EFW InstrumentNormal On-Orbit Operations Data Management and Data Products: 12 kbps daily average on-orbit (higher rates available in ground testing): ~ 5 kbps continuous Survey data: 32 S/s 3E (V1-V2, etc.) and 6V (V1s, etc.). 7-/13-bin broadband (~one-octave) digital filter products: up to 2 channels. Peak and Average amplitude estimate in each band. Used for on-board Burst2 selection. 16-, 36-, or 112-bin digital auto- and cross-spectral data products: Up to 8 SPEC and 4 XSPEC channels (typ. 4 SPEC, 2 XSPEC). ~ 7 kbps Burst1 and Burst2 data (0.5 and 16 kS/s E, V, and SCM data). ~19 bps Space Weather data products (to Space Weather Beacon): On-board spin-fit spin plane E-field (1 vector/spin). On-board SC potential estimate (1 scalar/spin). ~3 kbps ALT-MAG data product: Utilizes analog interface to EMFISIS-MAG used for on-board field-aligned coordinate transformation on E and MSC data in EFW IDPU. Backup Science and Ops (Guidance and Control) data path, available if EMFISIS-MAG sensor active, and EMFISIS-MEB not operational.

15. BACK-UP SLIDES

16. EFW Organization RBSP Project Office APL RBSP SWG EFW PI John Wygant UMN EFW Co-I team EFW PM Keith Goetz UMN EFW CAM Kim Cooper APL LASP lead Bob Ergun LASP UCB lead John Bonnell UCB SE Michael Ludlam UCB SMA Ron Jackson UCB Finance Kate Harps UCB LASP PM Mary Bolton LASP UCB PM John Bonnell UCB DFB SE Susan Batiste LASP Mechanical Paul Turin UCB Electrical Michael Ludlam UCB Flight Software Peter Harvey UCB Ground SW Will Rachelson UCB

17. Team members Minnesota John Wygant EFW PI JWygant@fields.space.umn.edu Keith Goetz EFW PM Goetz@umn.edu Berkeley John Bonnell UCB Hardware Co-I and UCB PM JBonnell@ssl.berkeley.edu Michael Martin Ludlam EFW System Engineer and IDPU Lead MLudlam@ssl.berkeley.edu Forrest Mozer UCB Science Co-I FMozer@ssl.berkeley.edu Kate Harps UCB Financial Manager Harps@ssl.berkeley.edu Ron Jackson SMA - Mission Assurance and Parts RonJ@ssl.berkeley.edu Jorg Fischer SMA - Parts and Mission Assurance Jorg@ssl.berkeley.edu Christopher Smith EFW Thermal Engineer CSmith@ssl.berkeley.edu

18. Team members Berkeley Dorthy Gordon IDPU - DCB FPGA Design dag@ssl.berkeley.edu Jane C. Hoberman EE - BEB, EFW-EMF I/F jch@ssl.berkeley.edu Rachel Hochman EE - Preamp RHochman@ssl.berkeley.edu Peter Berg EE - LVPS and Power Control pcb@ssl.berkeley.edu Peter Harvey Flight Software prh@ssl.berkeley.edu Paul Turin ME Lead pturin@ssl.berkeley.edu Gregory Dalton ME - SPBs gdalton@ssl.berkeley.edu Jeremy McCauley ME - AXBs jeremymc@ssl.berkeley.edu Bill Donakowski ME - IDPU Chassis billd@ssl.berkeley.edu Will Rachelson GSE Lead wrachelson@ssl.berkeley.edu Matt Born SDC Lead MattBorn@ssl.berkeley.edu

19. Team members LASP Professor Robert Ergun LASP Hardware Co-I REE@lasp.colorado.edu Mary Bolton LASP PM Mary.Bolton@lasp.colorado.edu Susan Batiste LASP Sys Eng Susan.Batiste@lasp.colorado.edu Wes Cole EE - DFB Analog Eng Wesley.Cole@lasp.colorado.edu Ken Stevens EE - DFB FPGA Design KStevens@EfficientLogicDesigns.com Magnus Karlsson EE - DFB FPGA Verification Magnus.Karlsson@lasp.colorado.com David Summers EE - DFB FPGA Verification David.Summers@lasp.colorado.edu David Malaspina DFB Science Support David.Malaspina@lasp.colorado.edu Trent Taylor LASP QA Trent.Taylor@lasp.colorado.edu Ex officio Dave Curtis EFW Former System Engineer dwc@ssl.berkeley.edu David Pankow Advising ME - Design and Boom Dynamics DPankow@ssl.berkeley.edu

20. InstrumentationDesigns IDPU AXB (1 of 2), Stowed SPB (1 of 4), Stowed

21. Spin Plane Deployment, Partially Deployed Cable, Pre-Amplifier Housing, Thin Wire, and Sphere

22. InstrumentationEngineering Test Units

23. Electric Fields & WavesDriving Requirements Spin plane component of E-field at DC-15 Hz (>0.3 mV/m or 10% sensitivity) over a range from 0 to 500 mV/m at R>3.5 Re …(IPLD 38) Spin axis component of E at DC-15 Hz (>4 mV/m or 20% sensitivity) over a range from 2-500 mV/m at R>3.5Re (IPLD 44) Spacecraft potential measurements providing estimates of cold plasma densities of 0.1 to ~50 cm-3 at 1-s cadence (dn/n<50%) (IPLD 55) Programmable high time resolutions burst recordings of large amplitude (Req.: 0.4 -500 mV/m capability: 0-4V/m) E-fields ; B-fields and cold electron density variations 0.1-50 cm-3 with sensitivity of 10% (derived from SC potential) over frequency range from dc to 250 Hz (IPLD 42,47,71, 59) Burst Interferometric timing of intense (0.1-300mV/m) small scale electric field structures and non-linear waves: timing accuracy of .06 ms for velocities of structures over 0-500 km/s (IPLD 61) Broad Band Filters (8 freq bins-peak or average) power in wave electric field at 8 samples/s. Burst Triggers/Selection Diagnostic; Solitary Wave Counter: Burst Diagnostic (IPLD 42,47,71,59,61) Spectra & Cross Spectra of average/peak electric and magnetic fluctuations from 1 Hz to 300 Hzwith a cadence of 1/8 seconds over a range 80 dB as a diagnostic of large amplitude wave properties over orbital scales. (IPLD 66,68). Low noise 3-D E-field waveforms to EMFISIS: 10 Hz to 400 kHz; maximum signal 30 mV/m. For spin plane sensors: range of 100 dB & sensitivities of 3 x 10-14 V2/m2Hz at 1 kHz and 3 x 10-17 V2/m2Hz at 100 kHz. For spin axis sensor pairs: range x 10 less & sensitivity x 100 less (IPLD 245, 246)

24. Primary Measurement Requirements Flow to Instrument

25. EFW Targeted Energization/Transport Mechanisms and Structures

26. Time Duration of Intervals of Low Frequency Bursting Necessary for Understanding Wave Fields Responsible for Scattering/Acceleration of Energetic Particles In order to obtain this data, we must have a burst memory of sufficient size, adequate telemetry to downlink the data,and a strategy for selecting the appropriate time intervals

27. Spin Plane Electric Field Measurement STARD Requirement at different altitudes including validity requirement

28. Measured and model average large scale convection electric field in inner magnetosphere. Traces are for different values of geomagnetic activity. Kp varies: 1-8. Quiet time field accurate to <0.2 mV/m. RBSP ~twice as accurate. Requirement is larger of either <0.3 mV/m or 10% of magnitude of E for Radial distance > 3.5 Re. CRRES accuracy of large scale electric field measurement on spacecraft comparable to RBSP after ground calibration

29. Observations of large amplitude turbulent electric fields E~+/-500 mV/m Duration of spike 20-200 Hz Polarized perpendicular to B B~0.5 nT (not shown) Hodograms for E and B Complicated quasi 3D structure full 3D and 3DB Waves electrostatic with phase fronts ~perp to B Large amplitude thermal plasma variations measured from SC potential variations:Result in order of magnitude changes in index of refraction wave time scales: trapping motivates SC potential measurements Position R=5.2, Mlat 25 deg, MLT=0.5 Observed during nearly conjugate ~400 keV electron microburst interval by low altitude SAMPEX. Polar Observations of Intense Waves Motivating High Time Resolution Burst Measurements

30. 1000 Large Amplitude Alfven Wave at PSBL with imbedded large amplitude LH “type” waves R=5.2 Re, 0.82 MLT, MLAT~25 deg Ez ~300 mV/m By~100 nT Propagate parallel to B tpwards Earth Vphase~ 3000-10000 km/s E-Field (mV/m) (~800 Hz) 0 25 duration burst Z GSM -1000 100 50 B-Field (nT) Y GSM Low freq (8 Hz) Notice:Imbedded bursts of high frequency waves ~1 V/m ptp (greater in other components) 0

31. EFW Burst Modes 1 and 2 In order to obtain high time resolution measurements of small scale waves and structures and not exceed its TM allocation the EFW instrument has two Bursts Modes with different memories and different means of selecting and playing back data: Burst 1: Nominal sampling 512 samples/s of 3D E-field and 3D Search Coil (from EMFISIS), Spacecraft Potential Density (Thermal Plasma Fluctuations). 32 Gigabytes of Memory. Filled in ~40 days. During TM contacts low rate survey data is sent to ground. Then over several days survey data is evaluated by EFW scientist for time intervals of substorm injections, shocks, and other structures driving waves. Desired burst times and priority are up-linked and the instrument forms a queue and sends data down. Autonomous modes and commanded time tagged triggers available. (7.5% duty cycle) 2) Burst 2: Interferometric Timing Measurements from Single ended measurements. (6.5 kHz time resolution). Autonomously triggered off large amplitude excursions using on board signals from DCB (~200 Mbytes). Bursts placed in queue on basis of “best trigger quality” and best played first. No human intervention (0.1% duty cycle) Diagnostic context for burst data over orbital scales is provided by spectra and cross spectra of E and B, broad band filters/peak detectors, and solitary wave counters. Information on burst status is provided to other instruments via burst status word via Spacecraft

32. Discussion of accuracy of VxB subtraction •Since the SC is moving relative to the Earth there is a motional electric field V xB where V is the spacecraft velocity and B is the measured magnetic field of the Earth which must be subtracted from the measured electric field in order to determine the electric field in the rest frame of the Earth. • Angular uncertainties in the attitude of the spacecraft or orientation of electric field or magnetic field or determination of spacecraft velocity measurements create errors in the electric field which must obey MRD/ELE 42. • Plots of typical motional electric field and uncertainties in the measured electric field for 1deg and 3 deg attitude errors as a function of radial distance for an ensemble of orbits is presented in the next slide • Required limits on angular error are defined in the subsequent slide • All errors are at the 3 sigma level • Time independent errors can be reduced signficantly (factor of 2-3) by on the ground cross calibration of the measured electric field and V x B for quiet time orbits as indicated by CRRES experience. Time independent errors are dominant contributions to the magnetometer boom angular uncertainties and electric field sensor alignment uncertainties. • CRRES was able to achieve an accuracy of ~ 0.1 mV/m after somewhat extensive ground calibration. This calibration is part of “scientific analysis”. The present RBSP EFW requirement is 0.3 mV/m at a distance of 3.5 Re. CRRES pointing accuracies were less stringent than RBSP.

33. Aspects of alignment calibration The magnetic field measurement compared to the magnetic field will provide a strong constraint on the alignment of the spacecraft within a rotation angle arround the magnetic field This angle can be constrained by comparison of the measured E to VxB during geomagnetically quite times Kp<2. The orthogonality of the V12 and V34 boom pairs can be constrained by using time intervals when VxB has a significant component in the spin plane. The sine waves measured by the rotating orthogonal booms pairs should be 90 degrees out of phase. Comparison of amplitudes of the sine waves to projection of VxB into spin plane provides calibration of magnitude. We can also use the 40m and 50 m boom baseline difference to calibrate the electric field magnitude. Attitude manveuvers will take place event ~27 days. After the attitude maneuvers it is possible that the sun pulse will provide the most accuracy attitude measurement. Since the sun sensor is most accurate when the spin axis points away from the sun. Many calibrations of time independent boom alignment error quantities are best preformed at these times.

34. Contributions to E field accuracy of transformation from spacecraft frame to inertial GSE frame E= Em-VxB Blue highlight indicates dominant contributions

35. Effect of Attitude Uncertainty in E-VxB subtraction accuracy

36. EFW/EMFISIS Amplitude vs Frequency