V5 Sensor Team: David Glaser, Dennis Seitz, John Bonnell, Gayle Martin Solar Probe Plus FIELDS V5 Sensor Pre-Environmental Review Engineering and Performance V5 Sensor Team: David Glaser, Dennis Seitz, John Bonnell, Gayle Martin

Outline Engineering Overview FM Hardware Performance Changes since CDR GSE and Red/Green Tag Items Documentation Status Environmental Test Matrix I&T Flow Functional Test Setup RFA Review

V5 FM V5 sensor provides a SC wake potential monitor and 3rd axis E-field measurement support from DC to 1 MHz. Simple monopole design with two 10 cm long cylindrical electrodes connected in parallel (Antenna). Antenna is current-biased to allow for DC and AC optimization of antenna sheath. Range is +/- 0.5 uA (smaller than V1234 due to eclipse/wake ops for Perihelion Science). Preamp enclosure (Box) is voltage-biased to allow for photo- and secondary electron control as needed (+/- 40 V authority). Preamp includes “Pre-Heat” resistor for use in cold start conditions, if needed (CBE not needed). Mass: 102.2 g (98 g NTE) Power: Preamp – 90 mW (130 mW NTE; 3 mA on ± 15VF) Pre-Heater Resistor – 90 mW (130 mW NTE; 10-kΩ on ± 15VF) NOTE: The Preamp and Pre-Heater are either/or, not together, and share the same power allocation.

Performance Electrical Performance meets or exceeds all requirements: Input Impedance (resistive and capacitive) Noise Levels (< few tens of nV/Hz1/2) Bandwidth (> 1 MHz) Size constraints limit the AC gain to ~.14 (small antenna capacitance, large base and input capacitances) – increases maximum amplitude of measured signals. In-flight calibration (sensor bias sweeps) will allow estimation of antenna sheath resistance which is dominant factor in determining rollover from resistive to capacitive coupling.

Design Changes Since I-CDR No significant changes to basic mechanical or electrical design of V5 since I-CDR. Modest changes in details such as surface finish, materials, and component values/inclusion: Harness feedthrough design changed from Gold-Plated PEEK to Aluminum for compatibility with harness crimp collar. Harness feedthrough connected explicitly to V5 Box potential via fastener-lug-jumper rather than mechanical contact. Mag Boom blanketing margin set at 0.250” to maintain electrical isolation of V5 Box and Antenna surfaces. Harness (pigtail) length and overwrap design finalized (identical to rest of Mag Boom harnessing). Belleville washers on Antenna fastener assembly deleted after LN2 dunk test demonstrated fasteners maintained adequate torque without them. Antenna spring contact force and compliance measured and large margins for maintaining contact during CTE and vibration cycles demonstrated. DC Mag Sniff test on EM revealed non-compliant materials (harness crimp) – replaced with appropriate non-magnetic flight materials on FM. Surface finish changed from Clear Alodyne to Black Nickel based on analysis and thermal balance test results. Thermal gasket material for mounting plane changed from ChoTherm to Micro-Faze K to accommodate low temperature of thermo-mechanical interface. Preheater resistor power switched from +/- 12V to +/- 15VF to simplify grounding and power (only +/- 15VF in V5 now), resistor value increased to 10 kΩ to keep power same. Changed thermal sensor RT1 from 1.00k to 2.00k due to flight stock availability. Deleted DDD protection diodes on preamp output (U1) output after DDD tests proved they were unnecessary. Deleted input series capacitor (C6) – not needed in this application. Replaced solder plating with gold plating on Antenna contact (E1) pad to improve mechanical and electrical contact. Addition of vent hole in V5 cover to meet venting requirements (offset holes in access bore for fastener).

GSE and Red/Green Tag Items NO GREEN TAG ITEMS. RED TAG ITEMS: V5 Red Tag Cover: Protects surface finish and antennas from snagging and marring. Provides electrical contacts to antenna and box surfaces for Functional Tests Bench Stand: Provides stable mounting surface for V5 and Red Tag Cover when V5 sensor is not mounted to Mag Boom.

Documentation Status Entrance Criteria (modified for sensor) Comment 1. Successful completion of the I-CDR and responses made to all CDR RFAs and/or a timely closure plan exists for those remaining open. Completed for V5 2. A preliminary I-PER agenda, success criteria, and charge to the board have been agreed to by the technical team, project manager, and review chair prior to the I-PER. Completed 3. The I-PER package (RE-001) is distributed 7 days in advance to members of the review board. Package should include the current version of the test verification matrix. Ref[1] Included 4. I-PER technical work products have been delivered and approved:   a. SW-005, Software Test Plan Update to Baseline(if changed since CDR); n/a b. TE-001, Instrument Verification, Validation, Test and Calibration Plans, Baseline. Ref[2],[3] included 5. I-PER technical work products listed below for both hardware and software system elements have been made available to the cognizant participants before or at the review: a. hardware fabrication and component level testing results; Ref[4] included b. CPT results on integrated hardware; Ref[5] included c. flight software testing results; d. travelers/work orders;  to be included with EIDP e. copy of all deviations and waivers; f. closed and open PFRs; g. test procedures; Ref[6],[7],[8] h. instrument acceptance criteria; i. command and telemetry list; j. updated design (hardware and software) documentation; To Be Presented k. current versions of the following deliverables:                                           i.    Performance Assurance Matrix; Ref[10] included                                          ii.    MA-002, FMEA(s); Ref[11] included                                         iii.    MA-002, Limited Life list;                                         iv.    MA-005, As designed parts list; Ref[13] included                                          v.    MA-006, Instrument Safety Data Inputs;                                         vi.    SE-001, Instrument Requirements Document; Ref[1] included                                        vii.    SE-002, ICD; Ref[12] included                                       viii.    SE-006, Instrument User’s Manual Information; Ref[9] included                                         ix.    SE-007, As designed Materials and Processes List; Ref[14],[15] included                                          x.    SW-002, Software Requirements Document. Required documentation for entrance to Sensor PER up to date and distributed. Vibe, Thermal, and Functional Test plans and procedures complete. No. References 1 SPF_SYS_010G_Instrument_Requirements - IRD 2 SPF_CDRL_TE-001-01B_V&V_Plan 3 SPF_MGMT_027_TC_Plan_D 4 SPF_PRE_V5_FM_SN002_FVT_results.docx 5 SPF_PROC_111_V5_FM_I&T_20161107.pdf 6 no reference 7 SPF_ANT_069_V5_FM_Vibe_Test_Procedure_RevC.docx 8 SPF_V5_TVcyclTestProc_DraftRevC.docx 9 V5 User Manual 10 SPF_SMA_010 7434-9096 SMA Requirements and Compliance Matrix_signed copy 11 SPF_CDRL_MA-002-01A FMEA 12 7434-9055_Rev_C_FIELDS_ICD_working_150820 13 SPF_PRE_V5_FM_BOM_REVA_20160812_AsKitted.xlsx 14 SPP-SMA-024B_v28_MPL_MIL_PAML_2016_10_21.xlsx 15

Environmental Test Matrix

I&T Flow – V5 Environmental Tests FM V5 Assembly Functional Test (Pre-Vibe) V5 Sensor PER TODAY V5 Vibe Test (Acceptance, Random and Sine) NN Nov 2016 1 day Functional Test (Post-Vibe/Pre-TVAC) Delivery to Fields I&T (Integration to MEP) Functional Test (Post-TVAC/Pre-I&T) V5 TVAC Test 06 Dec 2016 5 days

Electrical Functional Test Setup Continuity, isolation, and impedance – Antenna, Box, PWR, PRE HTR, BIAS, TMON, Chassis. Power consumption. DC and AC fucntionality: DC gain and polarity. 10 Vpp at 20 kHz. 4 Vpp at 1 MHz.

RFA Summary No Outstanding RFAs from the I-CDR, or Follow-On Design Review for V5: I-CDR RFA 4e: “Are the Bellville washers still included in the V5 design?” RESPONSE: yes. Later Bellville washers were removed from the design as they were not needed to maintain torque under vibe and thermal extremes. I-CDR RFA 10: “Summarize load cases for V5 HOT cases.” RESPONSE: closed, 6/29/2015.

BACKUP SLIDES

Harness Feedthrough Original Design was a single, gold-plated PEEK part, harness passed inside, jacket outside. In order to match with APL-provided collars, an aluminum sleeve was added

CTE LN2 Dunk Test/Elimination of Belleville Washer At CDR, a Belleville washer was used under the screw head that fastens each antenna to the box, to maintain fastener clamping at cold temperatures A286 steel (non-magnetic) Belleville washers are not available, so the Belleville was eliminated. CTE analysis shows that clamping force will decrease from 135 lbf to 113 lbf. A LN2 dunk test was performed and fastener torque was maintained.

BeCu Sping Contact Force Measurement  Trial lbf ±.03 1 1.04 2 3 4 1.26 5 1.20 6 1.24 7 8 9 1.25 Calculation and test to ensure that the spring contact maintains contact with the PCB during launch Calculation: Spring separation force at 55 GRMS (5σ) = 0.005 lbf Conservative force measurement: 1.0 lbf FIELDS required force ratio: 1.5 Actual force ratio: 200 Deflection of contact during assembly is 0.010-0.012” Max thermal contraction ~0.001”

PCB Mounting Screws and Feedthrough Grounding The flight design (already described on slides 14,15) has been further developed since the ICDR No A286 Panhead screws available – Socket heads with flat washers used instead Grounding lug placed beneath one screw Grounding lug placed beneath one feedthrough screw One washer trimmed to add electrical clearance

Surface Finish At CDR, the box and the dipoles had a clear Alodine finish After CDR, changed to electroless black nickel