THEMIS Instrument FM2/3 Pre-Environmental Review Electric Field Instrument (EFI)

1. THEMIS • Instrument FM2/3 • Pre-Environmental Review • Electric Field Instrument (EFI) • The THEMIS EFI, IDPU and II&T Teams

2. Outline • Summary of EFI Status at FM2/3 I-PER • Test Results To-Date (Instrument- and Suite-Level) • Summary • Vibration • TVAC • Electrical • PFR Status • Fulfillment of Mission Requirements • Tests To Be Completed at Suite Level

3. EFI Status at FM2/3 I-PER • Requirements and Design: • No major changes to Requirements or Design since M-CDR (see PFR Status for details). • All RFAs from previous reviews closed out (see following RFA response section). • Procurement: • All procurement is complete. • Personnel, Assembly and Test: • Team has done an amazing job. • 5 full FLT complements of SPBs and AXBs have completed functional and environmental testing, and either delivered to II&T or have completed II&T by the end of Aug ’05 (roughly 8 weeks per set). • BEB assembly complete in Dec ’04; bench testing through FM6 complete. • DFB assembly complete in Feb ’05; bench testing through FM5 complete. • Reduction in Force complete, Jun ‘05. • Final EFI team includes one half-time Scientist (Instrument Lead), one half-time MechE (shared with Probe I&T) and one half-time ElectE (shared with Probe I&T).

4. Changes To Testing, FM1->FM2/3 • Omnibus DFB Functional Test (Filter Bank, AKR Band, FFT, and Derived Quantities) added to Suite-level I&T tests in order to close the loop on requirement fulfillment by DFB. • Simulated preamp loads to be added to BEB floating supplies during IDPU/ESA TVAC BEB testing (PFR-061).

5. RFA Responses, FM1-I-PER • SPB Enable Plug Risks (All): • Response tendered describing failure mode and risk analysis behind decision not to perform Probe-level deploy testing of SPB systems. • Response accepted, and RFA closed. • Post-Failure Inspection and Replacement of AXB Sensor Door Axles and Associated Parts (FM3): • Response tendered describing failure mode and risk analysis behind decision to only visually inspect potentially affected parts in all AXB units, and replace visibly damaged parts in the affected unit (FM3 only). • Response accepted, but with qualification by Originator, RFA remains open pending further discussion between Originator and CogE.

6. F2/3 Testing To-Date (1) • Preamp • Special Thermal Qualification and Acceptance Test. • SPB and AXB • Cable Proof-Loading Test. • Fine Wire TVAC Deploy Test (SPB only). • Functional (Deploy) Test. • Vibration Test. • TVAC Test (Deploy and Functional Electrical). • Calibration (SciCal, with BEB). • Mass Properties and ICD Conformance. • BEB • Functional (Board-Level) Test. • DFB • Functional (Board-Level) Test.

7. F2/3 Testing To-Date (2) • EFI (Suite-Level Integrated Instrument) • DC- and AC-Functional Tests. • SPB Deploy Tests (Simulated and Actual). • AXB Deploy Tests (Simulated). • Fields Phasing and Timing Test. • DC- and AC-CMRR, Slew Rate Test. • Omnibus DFB Functional Test (Filter Bank, AKR, FFT, Derived Quantities). • Suite-Level CPTs (DC- and AC-Functional, Instrument Compatability).

8. Results of Flight Build Testing • DC and AC Transfer functions agree within Flight sets to better than 1 % on non-critical functions (USHER, GUARD, AC SENSOR gain, etc.), and better than 0.2 % on critical, matched functions (BIAS, DC SENSOR gain). • Full 16-bit control of all bias functions demonstrated (control to better than 1 part in 1000, as per MRD).

9. EFI Vibration Testing

10. SPB Acceptance Vibration Protocol • Per UCB THEMIS Document THM-SPB-PRO-423 • All 3 Axes • Sine Survey, .25 G, 5 – 2000 Hz • Sine Strength per Swales TM2430-RevD, 29 November 2004 • Random • Per Swales Document TM2430-RevD • 7.09 G RMS • 1 min duration • All Vibration Testing Performed at Same Facility, Quanta Labs • Retesting (if required) • ‘Workmanship Shake’ • Validate any design changes following original Flight build shake • Validate rework of any failures on previous vibration test • Entire vibration protocol, single axis only Acceptance Sine Strength Specification Acceptance Random Specification 4X SPB Flight Units on Vibration Plate

11. SPB Acceptance Vibration Test Summary (FM2/3 in Yellow)

12. SPB Vibration Testing Overview • Deviations from Test Specification (Notching/Force Limiting/Aborts) • None • SPB First Natural Frequency: 144 Hz (Requirement: >75 Hz) • Good Sine Sweep Consistency from Unit to Unit (within 15 Hz) • Retesting due to Hardware Failure: • Single Strand of Cable pulled out of connector at Spool (Assy error, FM3) • Resolution: Wire repaired, single axis re-vibe completed • Retesting due to Hardware Redesign • Release Ring Spring Redesigned to Ensure Constant Force on Doors • Resolution: All springs Replaced in all units • Single Axis Retest Completed • Preamp Ferrule Crimp Redesigned (Contact discovered to be inconsistent during testing) • Resolution: Ferrule material changed and recrimped • Single Axis Retest Completed • Status • Flight Units F1-F5 Vibration Acceptance Testing Completed. • F6 Scheduled for Vibration Sep 2005.

13. AXB Acceptance Vibration Protocol • Per UCB THEMIS Document THM-AXB-PRC-302 • All 3 Axes • Sine Survey, .25 G, 5 – 2000 Hz, 2 octaves/minute • Sine Strength per Swales TM2430-RevD, 29 November 2004 • Random per Swales Document TM2430-RevD • Qualification: 13.01 G RMS, 2 min duration • Acceptance: 9.21 G RMS, 1 min duration • All Vibration Testing Performed at Same Facility, Quanta Labs • Retesting (if required) • ‘Workmanship Shake’ • Validate any design/procedure changes following original Flight build shake • Validate rework of any failures on previous vibration test • Entire vibration protocol, single axis only

14. AXB Acceptance Vibration Test Summary FM2/3 in Yellow AXB X Axis AXB Y Axis Note: Jan 11 2005 testing was to qualification levels due to design modifications relative to the engineering test unit. AXB Z Axis

15. AXB Vibration Testing Overview • Deviations from Test Specification (Notching/Force Limiting/Aborts): • None on FM2 and FM3 units. • AXB Z First Natural Frequency: 300 Hz (Requirement: >75 Hz) • Good Sine Sweep Consistency from Unit to Unit (within 15 Hz) • AXB X & Y frequencies modeled fixture resonances, suggesting first natural frequency higher than 1800 Hz • Retesting due to Improper Test Procedure: • None on FM2 and FM3 units. • Retesting due to Hardware Failure: • Sensor door mount cracked during re-stow of boom (Assembly Error, FM3) • Resolution: Assembly replaced and single axis test completed • Status • Flight Units F1-F5 Vibration Acceptance Testing Completed • F6 (Flight Spare) Vibration Acceptance Testing Completed.

16. EFI TVAC Testing

17. EFI PreAmp Thermal Testing Status • NO CHANGE SINCE FM1 I-PER.

18. EFI SPB Thermal Testing Status • Updates since FM1 I-PER: • F4 and F5 SPB TVAC and Thermal Balance testing complete as of July 2005.

19. EFI AXB Thermal Testing Status • Updates since FM1 I-PER: • AXB F3 thru F6 received 6 Suite-level TVAC cycles en masse July 25-28, ’05 in order to deliver AXB and AXT (tube) to Probe I&T . • AXB F2 and F3 units delivered to Swales to support Probe RCS buildup, Aug and Sep 2005.

20. EFI PFR Status

21. PFR Status (1) Three PFRs relevant to FM2/3 Environmental Testing: PFR-065, PFR-072, PFR-085.

22. PFR Status (2) • PFR-065 (Malformed Packets in Continuous Mode): • FSW issue (see IDPU Presentation for details). • Does not stop FM2/3 environmental testing. • PFR-072 (Failed Actuation of FM2 SPB Doors): • Design issue with paired series connection of SPB door circuits and SMA end-of-travel switch on SPB Door Actuation circuit. • Issue recognized on FM2, and confirmed on FM3. • Actuation of one SPB of the pair would open the actuator circuit and prevent the other of the pair from opening. • Design modified to add shorting plug across end-of-travel switch to SPB Test/Enable Connector; Flight Enable plugs modified as well. • Design change keeps safety of end-of-travel switch throughout boom-level functional testing, while keeping one boom from locking out the other in Flight configuration. • Rework on all SPB Flight units complete, July 2005. Retesting of deploy cirucit completed on FM1, FM2, FM3, August 2005.

23. PFR Status (3) • PFR-085 (AKR Band Noise Floor is Too High): • Problem discovered in FM2 Omnibus DFB Testing, confirmed in FM3 and FM1 tests (generic problem). • Diagnosis on FM1, FM2, and FM3 shows problem is conducted noise from +/-10V floating power supplies at 150 kHz. • Noise floor was roughly 30 times over specification (around 100 mV, as compared to 4.5 mV pk amplitude for typical AKR signal). • X-axis floating power supply frequency changed to 1.2 MHz on LVPS (moved frequency out of AKR response band), and tuned LC bypass filter added between V1 and V2 inputs to AKR Band (HF Filter) circuit on DFB. • New noise level is less than 0.1 mV pk, resulting in an expected signal-to-noise ratio of around 40 (very good).

24. EFI Mission Requirements Fulfillment: • FM2 and FM3 MR fulfillment noted in THEMIS Verification Matrix (see MSE Presentation). • Integrated EFI and component parts compliant with mission requirements with following exceptions: • Noise level in 0-4-kHz band somewhat higher than MRD (few times 10-4 (mV m-1 Hz-1/2) rather than below that level) -> no significant impact, and requirement waived.

25. System Noise Level • EFI Spectral Coverage and System Noise Estimates Maximum Spectra (DC-Coupled) 1/f3 1/f flat CDI Measured EFI Noise Level BBF AKR band 1-LSB Spectra (DC-Coupled) Preamp and Rbias Current Noise Preamp Voltage Noise axial radial 10-Hz Ac-coupled roll-in Spin frequency 4-kHz Anti-aliasing roll-off

26. F2/3 Testing To-Be-Completed • IDPU/BEB • DC Functional Test in IDPU/ESA TVAC. • BEB floating supply current monitor testing in IDPU/ESA TVAC. • EFI • Suite-Level LPT/CPT throughout Environmental Testing. • TVAC SPB and AXB Deploy Test (Simulated).