1. Solar Probe Plus A NASA Mission to Touch the Sun Prof. Stuart D. Bale University of California, Berkeley The FIELDS Experiment

2. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 2 Agenda  Investigation team  Overview  Driving requirements  Primary measurement requirements  Design description  Interface definition  Heritage  Changes since Proposal  Technology development plan  Resource summary  Operations concept  Verification & validation  Risks & mitigation  Trades  Phase B plans

3. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 3 Investigation Team University of California, Berkeley University of Minnesota University of Colorado, Boulder NASA/Goddard Space Flight Center LESIA, Observatoire de Paris, Meudon LPC2E, CNES, Orleans PROMES, CNRS, Odeillo University of New Hampshire University of Maryland Smithsonian Astrophysical Observatory (SAO) University of Chicago Imperial College, London Queen Mary College, London IRFU, Uppsala

4. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 4 Design - Sensors Electric Field Antennas 2.3 m Tip-to-Hinge Magnetometer Boom MAG (Inboard)MAG (Outboard) SCM Main Electronics Package

5. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 Design – Block Diagram 5

6. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 6 Investigation Team and Heritage University of California, Berkeley (RBSP, STEREO, THEMIS, Polar, FAST, Cluster) University of Minnesota (STEREO, Wind, Ulysses) University of Colorado, Boulder (MMS, MAVEN, RBSP, THEMIS) NASA/Goddard Space Flight Center (RBSP, MAVEN, STEREO, Messenger, Wind) LESIA, Observatoire de Paris, Meudon (Solar Orbiter, Bepi-, STEREO, Wind, Ulysses) LPC2E, CNES, Orleans (Solar Orbiter, DEMETER) PROMES, CNRS, Odeillo University of New Hampshire University of Maryland Smithsonian Astrophysical Observatory (SAO) University of Chicago Imperial College, London Queen Mary College, London IRFU, Uppsala

7. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 7 Team Organization

8. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 8 FIELDS Science (1/4) 1.“Trace the flow of energy that heats and accelerates the solar corona and solar wind” FIELDS will measure : 1.Alfven waves and Poynting (energy) flux 2.Turbulent cascade and dissipation 3.Compressive waves and cyclotron damping 4.Magnetic reconnection and collisionless shocks 5.Velocity-space (expansion) instabilities 6.Signatures of ambipolar potential (exospheric physics)

9. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 9 FIELDS Science (2/4) 2.“Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind” FIELDS will measure : 1.Magnetic field polarity and flux tube structure 2.Reconnection current sheets 3.Statistics of (Parker) nano-/micro-flares 4.Streamer belt reconnection 5.Streamer belt latitudinal extent

10. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 10 FIELDS Science (3/4) 3.“Explore mechanisms that accelerate and transport energetic particles” FIELDS will measure: 1.Interplanetary shocks: Shock magnetic, electric, and density compression, foreshock waves, energy budget 2.Type II and type III radio bursts: Shock- and flare-related electrons, remote shock speed, throttling instabilities 3.Solar wind magnetic reconnection: Reconnection rate, exhaust structure 4.Stochastic (turbulent) acceleration: Fluctuation fields, compressive fluctuations, instabilities

11. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 11 FIELDS Science (4/4) 4.Interplanetary Dust (Bonus) FIELDS will measure: 1.Voltage spectral signatures of nanodust impacts 2.Voltage signatures of micron-scale dust impacts 3.Spatial distribution of dust particles in the heliosphere

12. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 12 FIELDS Measurements (1/4) FIELDS needs to make rapid measurements of intense fields -High cadence sampling -Burst memory system -Floating voltage preamps -Large dynamic range

13. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 13 FIELDS Measurements (2/4) Electric field bandwidth and dynamic range

14. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 14 FIELDS Measurements (3/4) Pre-Phase A Magnetic field bandwidth and dynamic range

15. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 15 FIELDS Measurements (4/4) Post-Phase A Magnetic field bandwidth and dynamic range REPLACE

16. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 16 Driving Requirements  Measurement dynamic range and sensitivity  E-Field measurement range  From 20V/m (DC) to 2µV/m (at freq > 1MHz assuming 25kHz BW)  B-Field measurement range  From 5000 nT (DC) to 0.5pT (at freq > 100kHz assuming 2.5kHz BW)  Sensor Accommodation  E-Field Antennas  Minimize effects of plasma wake, mitigate by locating right behind TPS  Requires uniform illumination of antenna pairs, symmetry with S/C  Magnetometers  Minimize magnetic interference from S/C, best mitigated with boom length  Self compatibility of SCM and FGM, minimum 1m distance separation  EMC / ESC / Mag Cleanliness  Minimize interference from all sources, across DC-20MHz BW  Can use similar EMC program as demonstrated on STEREO / RBSP  Environment  Antennas thermal / sun exposure  Instrument thermal (survival and operating, large swings in operating)  Thruster plume

17. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 17 Primary Measurement Requirements MRD RequirementParameterRequiredImplementation MRD-89Measure magnetic fieldDynamic range: 140dB Cadence: 100k vectors/sec Bandwidth: DC – 50kHz 2 x Fluxgate Mags 1 x SCM MRD-99 Measure electric fieldDynamic range: 140dB Cadence: 2M vectors/sec Bandwidth: DC – 1MHz 4 x 2.3m Antennas MRD-103 Measure plasma wavesDynamic range: 140dB Cadence: 1 spectrum/sec Bandwidth: ~5Hz – 1MHz DFB & TNR/HFR spectra MRD-107 Measure quasi-thermal noiseDynamic range: 100 dB Cadence: 1 spectrum/4sec Bandwidth: 10 – 2500 kHz TNR/HFR spectra MRD-108 Measure radio emissionsDynamic range: 80dB Cadence: 1 spectrum/16sec Bandwidth: 1 – 16MHz TNR/HFR spectra MRD-29 Provide burst mode capabilitySupport burst detection and S/C messaging TDS/DFB/ICU, up to 32GB burst memory

18. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 18 Design – E-Field Antenna Whip Stub Thermal Isolator Heat Shield Hinge / Damper Preamp Shown in deployed state Lower portion behind TPS Hinge Release Mechanism  Whip exposed beyond umbra  Operates at +1300º C  Material: Niobium C-103 tube  Heat shield: layers of Nb sheet  Stub: Ti tube, Sensor lead SS wire  Actuators: P5 Pinpullers  Two required, whip cage and hinge  Dampers control deployment speed  Antenna/preamp mass: 700g ea  Two outputs from Preamp:  LF: DC to 1MHz (to AEB & DFB)  HF: 10kHz to 20 MHz (to TNR/HFR & TDS)

19. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 19 Design – E-Field Antenna  Deployment  Need something here Stowed Antenna Deployed Antenna

20. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 20 Design – Antenna Configuration  Configuration on S/C  Antenna length: 2.3m  Tip-to-hinge length  Has ~0.4Hz response  Opposing antennas are colinear  Opposing antennas are equally illuminated  Antenna pairs are orthogonal  This is Preferred orientation  Can accept up to 5º non- orthogonality  Antenna crossing point is aligned with C/L of S/C  Antennas mount on TSA  Antennas are coplanar In a plane just behind TPS  This configuration moves antennas ahead of plasma wake

21. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011  Search Coil Magnetometer  3 axis LF antennas with HF winding on one axis  Embedded preamp  LF: 10Hz to 20kHz  HF: 1kHz to 1MHz  Sensitivity:  1x10 -2 nT/√Hz at 100 Hz  1x10 -5 nT/√Hz at 100kHz  Fluxgate Magnetometer  3 Axis, ring core  Three ranges:  ±512nT, ±8192nT, ±65536nT  Sensitivity: 0.1nT (in low range)  Bandwidth: DC – 32Hz 21 SCM MAG Design – Mag Boom Sensors

22. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 22 Design – Mag Boom Configuration Creates an integrated DC to 1MHz Magnetometer System  Separation distances are critical  Interference from S/C  Heritage shows that boom length is easiest method to mitigate S/C near field noise  Phase B trade study will determine accommodation, with 2m separation a goal  Sensor-to-Sensor interference  Tests have demonstrated that 1m separation is adequate  Magnetically coupled interference and sensor heater effects attenuated at this distance  Cable effects  Provide adequate shielding, magnetic cancellation, routing around sensors ≥0.7 m 1 m SCMMAG

23. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 Design – Main Electronics Package  TNR/HFR (Thermal Noise Receiver / High Frequency Receiver)  Power and cross spectra for QTN and RF emission to 20MHz  TDS (Time Domain Sampler)  Burst waveforms to 2Msps, event selection  MAG (Magnetometer Electronics 1 & 2)  Supports two fluxgate mags, 3 axes to 30Hz  DFB (Digital Fields Board)  Waveforms DC - 128ksps, LF power and cross spectra  AEB (Antenna Electronics Board)  Floating ground, antenna biasing, calibration source  ICU (Instrument Control Unit)  32 GB Burst Memory, S/C Data interface  LNPS (Low Noise Power Supply)  S/C power interface, EMC compliant 23  FIELDS MEP:  Mass: 6.2 kg (100mil wall)  Power: 14.8 W IMAGE-FUV MEP (above) THEMIS IDPU (below)

24. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 24  Data Interface: Command (TC), Telemetry (TM) and PPS  Redundant S/C C&DH  UART interface, 115kbaud, LVDS  Data transfers synchronized to 1PPS  Requires ICU to listen to both sides  Requires S/C to direct TC from one side only  Power Interface  Unregulated 28V (+7V/-6V), switched services  Survival Power  SCM and MAG heaters controlled via MEP, MAG requires AC heater  E-Field Preamps direct connection, DC heaters  S/C monitors temperatures  Actuator Power  S/C controls actuators directly, redundant Pin Puller interfaces FIELDS - S/C Interface

25. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 25  Interface purpose  Synchronization of data sampling  Exchange of real time data, e.g. MAG field data to SWEAP  High time resolution wave-particle correlations FIELDS – SWEAP Interface

26. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011  Addition of Low Noise Power Supply to MEP  AO specified that Instrument would receive secondary power from S/C  Change E-Field Antenna mounting, Increase length  AO specified a configuration that limited antenna length  Configuration now is lower mass than proposed  Added SWEAP Interface  Reduction in Telemetry  From 32Gb/orbit to 20Gb/orbit (avg) plus Science Campaign allocations Changes since Proposal 26 Proposed version Antenna Shown deployed Picture of current antenna here

27. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 27 Technology Development Plan FIELDS E-Field Antennas  Description  E-Field Antennas, whips and heat shield exposed to Sun  Driving Requirement  Antennas must have unobstructed illumination, provide E-Field sensing at temperatures ~1500ºC  Key Development Milestones  Material selected pre-Proposal (Niobium C-103)  Coupon testing at PROMES solar furnace  Verified optical properties  Thermal models correlated w/ S/C models (Phase A)  Phase B development plan  Coupon level testing to verify EOL properties  Model testing at PROMES to verify thermal model  Photoelectron emission testing  Demonstrate TRL6 by PDR  Risk Mitigation  Testing begins in Nov 2011  Alternate materials (Tantalum, Rhenium) Whip Heat Shield Need a view of this that includes TPS

28. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 28 Resource Summary - FIELDS CBE (Margin)  Mass: xx (xx) kg  Power: xx (xx) W  Telemetry volume: xx Gbit/orbit  Additional telemetry used in campaign mode: xx Gbit  Burst mode

29. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 29 Operations Concept  (1 page)  Commissioning  Normal operations (eg. No duty cycling)  Bursting (if applicable)  Command and data handling  SOC Operations will be run from institution name

30. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 30 Instrument Verification & Validation Plan Unit Mass Props VibeCPTTVACEMI/EMCMAG Boom Deploy Interface Test Calibration Antenna √√√√√√√ Preamp √√√√√ MAG √√√√√√ SCM √√√√√√ MEP √√√√√√√ FIELDS Suite √√√√√ THEMIS Instrument Suite in TVAC Large TVAC Chamber at UCB PROMES Solar Furnace, Odeillo, France

31. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 31 S/C Level Instrument V & V Plan FIELDS Will Support APL’s Verification of Spacecraft FIELDS Flow Will be as Simple as Possible Expect “Bolt-Hole” Alignments are Sufficient for Boom Systems Fields Phasing EMC Electrostatic Cleanliness Boom Deploy Functional Test CommandingCompatibilityCPT FIELDS - Space craft √√√√√√√ FIELDS - SWEAP √√√√ Unit AlignmentsVibeCPTTVACEMI/EMCMAG Boom Deploy Interface Test Calibration FIELDS - Mag Boom √√√√√√√√√

32. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 Likelihood of Occurrence (probability) Consequence of Occurrence (Impact) 5 4 3 2 1 12345 P = Performance C = Cost S = Schedule M = Mass P F1 Evaluation Date: 8/10/11 P F2 CS F3 P F5 P F6 P F7 PSM F8 PS F9 FIELDS Instrument Risks Status IDTitlePICritRetire At F5 Survival Thermal Environment 44H SCM & MAG Env. Qual (~11/14) F9 Magnetic Sensor Qualification 34M MAG Thm Test by I-CDR (~1/15) F12 Magnetic Cleanliness 43M Mission I&T (~8/16) F10 Antenna Qualification 33M Ant. Qual (~3/13) F7 ElectroStatic Contamination 33M Mission I&T (~8/16) F8 Magnetic Sensor / SCM dynamic range 33M MAG/FGM Trade (~4/12) F6 Magnetic Sensor Interference 23L ETU I&T (~8/14) F3 Foreign Funding Issues 14L CNES Phase C Commit. (~12/13 TBR) F11 SCM dependence on Solar Orbiter 22L SO FLT SCM Complete F1 S/C Conducted and Radiated Noise Contamination 13L Mission I&T (~8/16) F2 Plasma Wake Effects 13L Mission CDR (~3/15) CS F10 CS F11 P F12 32 Mitigation Plans in Place for All FIELDS Risks

33. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F5-P: Survival Thermal Environment Event Date Assessment** Likeli- hood Conse- quence Risk Grade AGSFC MAG Ops & Survival Thermal Test12/1134 12 BAPL implement high-efficiency blankets and higher heater power allocation by I-PDR06/1324 8 CThermal Analysis/Test to confirm the thermal design is adequateTBD14 4 DSCM & MAG Environmental Qualification11/14Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F5-P: Survival Thermal Environment Current Assessment HIGH LikelihoodConsequence Risk Grade Risk Statement If S/C does not provide adequate survival heater power, 44 16 Then FIELDS may fail due to cold temperatures. Last Updated08/10/11 A B C D F5-P: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

34. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 Likelihood of Occurrence (probability) Consequence of Occurrence (Impact) 5 4 3 2 1 12345 P = Performance C = Cost S = Schedule M = Mass P F1 Evaluation Date: 8/10/11 P F2 CS F3 P F5 P F6 P F7 PS F9 FIELDS Risks Status Anticipated at End of Phase B IDTitlePICritRetire At F5 Survival Thermal Environment 24M SCM & MAG Env. Qual (~11/14) F9 Magnetic Sensor Qualification 24M MAG Thm Test by I-CDR (~1/15) F12 Magnetic Cleanliness 33M Mission I&T (~8/16) F10 Antenna Qualification 33 Ant. Qual (~3/13) F7 ElectroStatic Contamination 23L Mission I&T (~8/16) F8 Magnetic Sensor / SCM dynamic range 33 MAG/FGM Trade (~4/12) F6 Magnetic Sensor Interference 13L ETU I&T (~8/14) F3 Foreign Funding Issues 14L CNES Phase C Commit. (~12/13 TBR) F11 SCM dependence on Solar Orbiter 12L SO FLT SCM Complete F1 S/C Conducted and Radiated Noise Contamination 13L Mission I&T (~8/16) F2 Plasma Wake Effects 13L Mission CDR (~3/15) CS F11 P F12 34 FIELDS Risk Posture Improved by end of Phase B

35. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 FIELDS Phase B Risks Mitigation FIELDS Risk Mitigation activities for Phase B include: Antenna Qualification: Nb materials testing, optical props aging (~3/12, Odeillo, France) Antenna model thermal testing (~3/13, Odeillo, France) Additional contingency test, if needed (TBD, Odeillo, France) SCM / MAG / FGM Trade: Determine the optimal technical (dynamic range) & resource (mass and thermal) solution (close by 4/12) See Trades Slide for additional information. MAG Performance Over Temperature: MAG Cold Performance Test (~12/11) MAG Thermal Cycling Test (end of Phase B) MAG/SCM Interference: MAG/SCM Interference test (similar to the MAG/FGM test performed in 7/11) (~4/13, Chambon, France) 35

36. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 Phase B Magnetometer Trade 36 Trade OptionPerformance/RiskImpact on Resources Existing sensors for SCM and MAG High level fields, esp. at LF can saturate SCM. Decreasing SCM gain risks proven sensitivity. None Dual SCM, one high gain, one low gain Provides both high sensitivity and wider dynamic range capability. From science standpoint is safest solution. Increased mass, power, data budget. Could maintain data volume by switching. One SCM with dual range preamp Switchable gain is an unfunded development. Feasibility testing in Phase A has demonstrated an approach. Requires TRL demonstration. Minor impact to mass and mounting volume. Expanded range MAG; SCM with shifted freq. response Modify freq. at which magnetometers cross over. Sample MAG at ~250Hz. Lower SCM exposure to large LF fields. Increase in MAG data volume, small increase in FIELDS data

37. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 37 FIELDS Phase B Plans

38. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 SPP MDR 4-6 October 2011 38 FIELDS Instrument Backup

39. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 39 Primary Measurement Requirements MRD RequirementParameterRequiredComment/Heritage MRD-34 Ensure absolute time knowledge accuracy Within +/- 1sec (3σ)ICU board in MEP MRD-115 Correlate data to thruster firing Accept S/C input indicatorICU MRD-48, -49 Support real-time, time tagged commands Accept S/C command inputICU MRD-52 FIELDS science dataCollect and process data, interface with S/C TLM ICU MRD-53 Instrument commissioningSupport real-time deployment and calibration All flight elements MRD-54 Provide real-time housekeeping data Monitor critical voltages, currents, temperatures in instrument All flight elements MRD-18 Data post processing and delivery Comply with data processing, delivery, archiving requirements SOC MRD-13 EnvironmentComply with mission Environment, EMC, Contamination controls All flight elements

40. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 P = Performance C = Cost S = Schedule M = Mass ID Risk Mitigation Plan F1-P: S/C Conducted and Radiated Noise Contamination Event Date Assessment** Likeli- hood Conse- quence Risk Grade AEMI/EMC Plan Draft prior to I-PDR06/1313 3 BEMI/EMC Plan Final prior to I-CDR01/1513 3 CEMC verification at Mission I&T08/16Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F1-P: S/C Conducted and Radiated Noise Contamination Current Assessment LOW LikelihoodConsequence Risk Grade Risk Statement If S/C design does not include EMI shielding and EMC mitigations 13 3 Then FIELDS will not be able to measure small signals as required Last Updated08/10/11 LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 F1-P: Risk Burn Down Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016 BC A

41. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F2-P: Plasma Wake Effects Event Date Assessment** Likeli- hood Conse- quence Risk Grade AAccept risk at Mission CDR when design freezes with adequate boom length.03/15Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F2-P: Plasma Wake Effects Current Assessment LOW LikelihoodConsequence Risk Grade Risk Statement If S/C plasma wake effects are as large as predicted, 13 3 Then near-S/C electric field sensors will be compromised. Last Updated08/10/11 F2-P: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016 A

42. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F3-CS: Foreign Funding Issues Event Date Assessment** Likeli- hood Conse- quence Risk Grade AFund backup options for TNR and SCM09/1114 4 BDecision to proceed with foreign sources for SCM & TBR06/1214 4 CCNES proposal for next phase09/1214 4 DKDP-C11/1314 4 ECNES Phase C Commitment 12/13 (TBR) Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F3-CS: Foreign Funding Issues Current Assessment LOW LikelihoodConsequence Risk Grade Risk Statement If foreign funding sources fail 14 4 Then we may lose the search coil sensors or electronics Last Updated08/10/11 BC F3-CS: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016 A D E

43. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F6-P: Magnetic Sensor Interference Event Date Assessment** Likeli- hood Conse- quence Risk Grade AMAG Boom design accommodates >1m separation yb I-PDR06/1313 3 BETU I&T complete08/14Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F6-P: Magnetic Sensor Interference Current Assessment LOW LikelihoodConsequence Risk Grade Risk Statement If the MAG and SCM sensors are too close, 23 6 Then their interference will compromise the magnetic measurements. Last Updated08/10/11 A B F6-P: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

44. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F7-P: Electro Static Contamination Event Date Assessment** Likeli- hood Conse- quence Risk Grade AESC plan draft complete, prior to I-PDR06/1323 6 BESC plan final, prior to I-CDR01/1513 3 CESC verified at Mission I&T8/16Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F7-P: Electro Static Contamination Current Assessment MEDIUM LikelihoodConsequence Risk Grade Risk Statement If the S/C has areas that charge up, 33 9 Then their potential will compromise the electric field measurements. Last Updated08/10/11 F7-P: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016 A B C

45. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F8-PSM: Magnetic Sensor / SCM Dynamic Range Event Date Assessment** Likeli- hood Conse- quence Risk Grade AMAG/FGM Trade Closure04/12Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F8-PSM: Magnetic Sensor / SCM Dynamic Range Current Assessment MEDIUM LikelihoodConsequence Risk Grade Risk Statement If the combined MAG & SCM concept does not cover the required dynamic range and bandwidth, 33 9 Then there may be a loss of data in certain frequency bands. Last Updated08/10/11 A F8-PSM: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

46. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F9-PS: Magnetic Sensor Qualification Event Date Assessment** Likeli- hood Conse- quence Risk Grade APlan thermal testing of a representative MAG sensor (by I-PDR)06/1324 8 BMAG Thermal Test by FIELDS Instrument CDR01/15Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F9-PS: Magnetic Sensor Qualification Current Assessment MEDIUM LikelihoodConsequence Risk Grade Risk Statement If the MAG sensor is not qualified for the number of operational thermal cycles, 34 12 Then the sensor may fail in orbit. Last Updated08/10/11 A B F9-FS: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

47. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F10-PS: Antenna Qualification Event Date Assessment** Likeli- hood Conse- quence Risk Grade AObtain Nb materials for testing~01/1223 6 BComplete Nb coupon testing03/1213 3 CAntenna ETU thermal testing; Antenna Qualification Complete03/13Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F10-PS: Antenna Qualification Current Assessment MEDIUM LikelihoodConsequence Risk Grade Risk Statement If the antenna cannot be qualified to meet thermal requirements, 33 9 Then the antenna will need to be re-designed. Last Updated08/10/11 A B C F10-PS: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

48. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F11-S: SCM Dependence on Solar Orbiter Event Date Assessment** Likeli- hood Conse- quence Risk Grade ASolar Orbiter ETU completeTBD12 2 BRe-plan SCM ETU testing as neededTBD12 2 CRe-plan SCM FLT integration as neededTBD12 2 DSO Flight SCM CompleteTBDRetire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F11-S: SCM Dependence on Solar Orbiter Current Assessment LOW LikelihoodConsequence Risk Grade Risk Statement If Solar Orbiter is delayed, 22 4 Then the SCM for FIELDS delivery will be delayed. Last Updated08/10/11 A B C D F11-S: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016

49. Solar Probe Plus A NASA Mission to Touch the Sun Solar Probe Plus Mission Definition Review October 4-6, 2011 ID Risk Mitigation Plan F12-P: Magnetic Cleanliness Event Date Assessment** Likeli- hood Conse- quence Risk Grade AMagnetics plan draft (prior to I-PDR)06/1333 9 BMagnetics plan final (prior to I-CDR)01/1523 6 CDesign freeze at M-CDR confirms long-enough MAG Boom03/1513 3 DMagnetics verified at Mission I&T08/16Retire Risk * Grade = Likelihood x Consequence ** Assessment is the remaining risk assessed after successful event completion Risk Grade 25 20 15 10 5 Risk F12-P: Magnetic Cleanliness Current Assessment MEDIUM LikelihoodConsequence Risk Grade Risk Statement If the S/C exhibits high residual magnetic fields (AC or DC), 43 12 Then the magnetic measurements will be contaminated. Last Updated08/10/11 A B C D F12-P: Risk Burn Down P = Performance C = Cost S = Schedule M = Mass LevelRisk Grade* High 15-25 Medium 6-12 Low 1-6 Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 201120122013201420152016