mpsrefi- 1 ucb, oct 26, 2006 themis mission pre-ship review “our gateway to the cape…” the...

MPSR EFI- 1 UCB, Oct 26, 2006

THEMIS MISSION

PRE-SHIP REVIEW

“Our Gateway to the Cape…”

The Electric Field Instrument (EFI)John Bonnell

University of California - Berkeley


Outline

•Summary of EFI Status at Mission PSR•Final Test and Cal Results vs. Requirement Fulfillment•PFRs and RFAs since MPER.


EFI Status at Mission PSR

• All PFRs closed out (see PFR Status for details).• All RFAs from previous reviews closed out or responded to (see

RFA Status for details).• EFI on all five probes performing in-spec and in-family; all

requirements fullfilled.


EFI Mission Requirements Fulfillment:

• F1 through F5 Mission Requirements fulfillment noted in THEMIS Verification Matrix (see MSE Presentation).

• Integrated EFI and component parts compliant with mission requirements.

Mission Requirements Fulfillment


Results of Performance 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).

• V- and E-channel gains on DFB as per specification.• DFB Spectral (Filter Bank, FFT, and AKR) and Derived Quantities

data products as per specification.• Noise, DC Functional, AC Functional, and DAC Test results

consistent, in-family and in-spec across all probes and throughout environmental testing (see Bonus Materials for example performance test outputs).


PFR & RFA Status (1)

• New PFRs pertaining to EFI since Mission PER:• PFR-181, F3 EFI IMON Instability (also MPER RFA-2).• PFR-183, F3 AXB V6 Functional Test Anomaly.• PFR-206, F4 AXB Temperature Sensor Reading Anomalously (1052 C).

• RFAs pertaining to EFI:• MPER RFA-2, Monitoring for Excess Current on EFI Instrument.



• PFR-183, F3 AXB V6 Self-Test Anomaly• During Mission I&T, the V6 channel of the F3 EFI responded anomalously during DC and AC Functional Tests.• Anomalous response traced to portion of internal test circuit, rather than EFI sensor functionality (ACTEST line connection).• Anomalous response is understood and repeatable, and so does not affect ability to determine state-of-health on-orbit.• Further diagnosis and re-work would require significant disassembly of core spacecraft structure and sub-systems (AXB tube; RCS; etc.), and would engender significant additional risk.• MGSE used during JPL testing to ensure consistent response in functional tests.• Unit will be flown AS-IS.



• PFR-206, F4 AXB Temperature Sensor Reading 1052 C• The AXB temperature sensor on F4 began to respond anomalously in a post-vibe LPT at JPL (1052 C at ambient; probe not obviously on fire or melting).• Anomalous reading corresponds to open condition on temperature sensor, based on bench tests with F6 Flight Spare.• By design and construction, open condition poses no threat to operation of EFI:

• Open circuit on temperature sensor does not affect functionality of EFI sensor.• Temperature sensor is physically isolated from EFI Preamp.• Supply lines for temperature sensor electrically isolated from EFI Preamp.• Open circuit poses no risk to sensing circuit or HSK on BEB.

• Loss of AXB temperature sensor does not affect ability to calibrate and operate the EFI on F4 on-orbit.• Further diagnosis and re-work would require significant disassembly of core spacecraft structure and sub-systems (AXB tube; RCS; etc.), and would engender significant additional risk.• Unit will be flown AS-IS.



• EFI Current Consumption (PFRs 096 and 181, MPER RFA-2)• Floating supply current consumption of EFI during ambient functional tests has shown marked variability over time and between axes and probes (up to a factor-of-two increase over nominal).• This variability does not occur during TVAC testing, and thus is not expected to occur during on-orbit operations.• Performance of EFI as measured by normal functional testing and more detailed case studies remains in-spec and in-family over time and between axes and probes. No oscillation or other malfunction of preamps seen during episodes of increased current consumption.• Excess current consumption amounts to 1-2 mA/preamp/supply, and represents no threat to LVPS floating supplies, either through voltage droop or excess loading (supplies handle 4x nominal current without significant droop).• Uptake of moisture by hygroscopic preamp PWB material (Thermount) and resulting high-impedance (>30-kohm) leakage path in PWB now most likely source of increase current consumption.• Further diagnosis and re-work would engender significant additional risk due to disassembly, invalidation of testing, etc.• Increase current consumption not expected to occur on-orbit, and does not affect EFI or LVPS performance, so units will be flown AS-IS.



IMON vs. Test Type:1 = LPT @ Ambient

2 = TVAC3 = CPT @ Ambient

40

50

60

70

80

90

100

110

120

0.5 1.5 2.5 3.5

Test Type

IMO

N [

mA

, pri

mar

y]

min(IMON) vs. Test Type

max(IMON) vs. Test Type

TVAC currents are nominal


Bonus Content


EFI IMON by Probe, Axis, and Test Type


Example Performance Test Data –Housekeeping (APIDs 404 and 406)

404 – SOH1 HSK


Example Performance Test Data –Housekeeping (APIDs 404 and 406)

406 – SOH2 HSK


Example Performance Test Data –Spectral (APIDs 440, 44D and 44E)

440 – Filter Banks



44D – PtclBurst FFT



44E – WaveBurst FFT


Example Performance Test Data –DC Functional (Waveform V and E)

441, 443 – Fast Survey V and E



445, 447 – Ptcl Burst V and E



449, 44B – Wave Burst V and E


Example Performance Test Data –AC Functional (Waveform V and E)

449, 44B – ACTEST, evens.


Example Performance Test Data –AC Functional (Waveform V and E)

449, 44B – ACTEST, odds.


Example Performance Test Data –DC and AC Functional (449, 44B)

449, 44B – Noise, DC & AC Functional.

mpsrefi- 1 ucb, oct 26, 2006 themis mission pre-ship review “our gateway to the cape…” the...

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