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Presented by P. Mosner/R. Geßner Astrium GmbH

MIPAS In-Orbit Operation. Presented by P. Mosner/R. Geßner Astrium GmbH. Contents. Part1 (P. Mosner) : Switch-On and Data Acquisition Phase (SODAP): History MIPAS Anomalies (1) - Mechanisms Modifications to Operational Procedures. Part2 (R. Geßner) :

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Presented by P. Mosner/R. Geßner Astrium GmbH

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  1. MIPAS In-Orbit Operation Presented by P. Mosner/R. Geßner Astrium GmbH

  2. Contents • Part1 (P. Mosner) : • Switch-On and Data Acquisition Phase (SODAP): History • MIPAS Anomalies (1) - Mechanisms • Modifications to Operational Procedures • Part2 (R. Geßner) : • MIPAS SODAP and CAL/VAL Characterisations • Operational Aspects of Instrument Performance • MIPAS Anomalies (2) - Miscellaneous • Long-Term Observations • Summary

  3. Part 1

  4. MIPAS Switch-On and Data Acqusition Phase (SODAP) - History • Locking of MIPAS coolers at L – 6 hours 28 February 2002 • Launch01 March 2002 01:07 UTC • Principal MIPAS switch-on Sequence during SODAP • ICU switch-on 11-13 March 2002 • -> OLB-B thermostat anomaly, was resolved later • Unlocking of ASU, ESU, INT 17 March 2002 • Transition Standby -> Heater 18-19 March 2002 • Cooler and CBB characterisation 20-23 March 2002 • First MIPAS measurements 24 March 2002 • Timing characterisations 24-26 March 2002 • Handover to MPS 26 March 2002 • SODAP -> CAL/VAL Phase handover begin April 2002

  5. MIPAS Anomalies (1) - ESU stepsize limitation • A HEATER MCMD resulted in a transition to HTR/REF Mode • Explanation : • the Heater MCMD occurs at a time where the requested Heater Mode transition can cause a conflict with activities finalising the ongoing sweep • this occurs only if ESU step sizes larger than the instrument specification value are commanded, which was demonstrated by tests on EQM at Ottobrunn • Operational solution: • every Heater MCMD is preceded by an Elevation Wear Cycle (in this case the surveillance related to the failure is inhibited for a short period of time) • BUT: the conflict may occur for other type of commanding where such a solution is not possible

  6. M1,M2 M5,M6 M3,M4 Slide 1 stop after init Slide 1 End Stop Slide 2 stop at neg. end Neg. End Slide 2 Positive Direction Pos. End LockPosition Initialisation Marks MIPAS Anomalies (1) - Interferometer initialisation • An IDU re-initialisation failed (after non-nominal switch-off) • Explanation : • After a non-nominal IDU switch-off it can occur that both IDU slides are outside the init marks (Slide 1 being at positive APS side, Slide 2 at negative APS side. If this is the case the failure occurs due to • The slide 2 stops than at the neg. end stop behind the lock position • The lock position rail insert presents a small step on the rail where a velocity error can occur

  7. MIPAS Anomalies (1) - Interferometer initialisation • Operational solution: If the IDU isn’t initialised after the transition from Standby to Heater, it is required to perform 3 times the following initialisation steps after reaching Heater Mode: - initialise the IDU slides - move slide 1 to the negative rail end and slide 2 to the positive rail end

  8. MIPAS Anomalies (1) - Cooler performance • MIPAS instrument was switched off due to cooler vibration failure • Failure Observations and Explanation : - The cooler accelerations increased extremely (acceleration increase from <3mg to 12 mg; 1st harmonic acceleration increased by 50 times)This was caused due to loss of proportionality between compressor/displacer B drive level and amplitudes/PPO outputs • The proportionality for compressor B failed due to a mis-adjustment of the phases and amplitudes for the 1., 2. and 3. harmonics by the VCS. All of these harmonics correction products are processed and corrected individually. • The probable reason was the ageing of the VCS setting due to the long “on-line” operation without a repeated learning cycle • Operational solution(still under discussion): • Every 2-4 weeks (TBC) perform 5 VCS re-learn cycles (in Heater Mode) • If the failure re-occurs stop and re-start cooling once per month

  9. Modifications to Operational Procedures • Mode Transition Standby to Heater: • Special IDU initialisation to correct IDU init problems • Start Measurement: • Update PAW gain setting for Measurement (switch PAW table 1) • Stop Measurement (Trans. Measurement to Heater): • the Heater MCMD is preceded by an Elevation Wear Cycle to allow the higher elevation stepsize (as discussed before) • Update the PAW gain setting, if a LOS/CAL sequence follows (PAW table 2) • Non-Linearity Characterisation: • New procedure added • Change due to limitation from the non-availability of ARTEMIS • Update SPE filter set: • Procedure added

  10. Part 2

  11. MIPAS Characterisation in SODAP and CALVAL • Timing Characterisation • Mode Transition Times • Duration of Operational Sequences • Temperature Characterisation • MIPAS Optics Module / Interferometer • Calibration Blackbody • MIPAS Anomalies: Complementary Failures

  12. OFF Functions 11.050 sec 11.052 sec BB CAL Nom. MEAS 20.000 sec 20.035 sec DS CAL SEM < 55 hrs 35.5 hrs 10.200 sec 10.203 sec HEATER STANDBY LAUNCH LOS CAL 11.050 sec 11.063 sec 20.000 sec 20.014 sec MIPAS Timing Characterisation: Mode Transition Times • Correlation between MCMD TT and time stamp of Source Packet

  13. MIPAS Timing Characterisation: Summary (1) • Mode Transitions : • Heater to Measurement:20.035 sec  5.9 ms - > higher than values on-ground due to shift of ZPD position to align forward and reverse sweeps; effect understood • Heater to LOS CAL:11.063 sec  0 ms(IOM: 10.066 sec) 20.014 sec  8.2 ms • Meas. to SEM,DS,BB:11.052 sec  5.9 ms 10.203 sec  3.9 ms

  14. MIPAS Timing Characterisation: Summary (2) • Duration of activities: • Elevation Scan Sequence (ESS - 16 high resolution sweeps): 71.202 sec  5.8 ms(design value: 71.200 sec) • ESS Sequence (5 ESS + Offset Calibration): 387.610 sec  8.4 ms(design value: 387.600 sec) • INT turnaround time: 0.450 sec  4.5 ms(design value: 0.450 sec) • Low Resolution Sweeps: 0.400 sec (0.4 sec) • Medium Resolution Sweeps: 2.002 sec (2.0 sec) • High Resolution Sweeps: 4.003 sec (4.0 sec)

  15. Interferometer temp MIO Baseplate temp MIPAS Temperature Characterisation: Optics Module • MIO temperature increase in the mission: 216 K (L+10 days) -> 221 K (L+25 days) -> 224 K (L+ 68 days) • MIO baseplate orbital temperature variation: 0.2 K p-p, but Interferometer remains very stable (hence also the Beamsplitter)

  16. MIPAS Temp Characterisation: CBB Temperatures (1) • CBB temperature profile shows 3 effects: • Temperature increase by about 1.7 Kwhen MIPAS is switched into Measurement Mode - > ASU shutter opens and the CBB sees parts of the atmosphere via the side baffle • Temperature change by about 3 Kwhen CBB heater level is changed by one step (0.27 W) • Orbital oscillation by about 0.2 K

  17. Orbital variation MIPAS to Measurement CBB HL= 6 CBB HL= 4 CBB HL= 5 MIPAS to Measurement MIPAS to Heater Mode MIPAS Temp Characterisation: CBB Temperatures (2)

  18. MIPAS Temp Characterisation: CBB Temperatures (3)

  19. Operational Aspects of Instrument Performance • Radiometric, spectral or ILS performance : no operational impacts so far • LOS pointing performance: • analogue gain setting needs to be increased for LOS Calibration (poor signals especially in Channel D2) • first LOS signal (crosscorrelation peak) in a series of star measurements still earlier than expected; no major impact since other measurements “rectify” the CC peak; nevertheless explanation required • Gain measurements reveal some deterioration of optical throughput in the range of a few percent;could be contaminants (ice) on the detectors -> similar effects observed on other ENVISAT instruments -> operational impact for MIPAS: may require Decontamination Heating -> however: risk of this kind of cooler operation needs to be traded against the performance degradation -> going back to STANDBY (Coolers OFF) may be sufficient

  20. MIPAS Gain Drift of about 6% within 224 orbits (about 15 days)

  21. MIPAS Anomalies (2) - Complementary Failures • SPE related error messages • Occasional “SPE correctable memory fault” reporting (EDAC) • Occurrences of an “unexpected sample count” - no impact on GS detected so far (not all L0 data available) • Occurrences of “ICE AUX Data not included” (5-6 events per day - but relatively poor statistics) - results in a loss of the SP’s from the respective sweep -> seems to be SPE-ICE communication problem - not correlated to Orbit position nor Instrument activity - not observed during EQM testing initiated immediately in OTN -> not really understood -> to be observed

  22. Required Long-term Observations (1) - MIPAS Mechanisms • ASU/ESU : • Lifetime limited aspects (ESU leadscrew rotations) - some margin • Interferometer: • Monitor the warning anomaly flags (history reporting at ESOC)- Slide Movement Force Warning (1N Force)- Differential Speed Warning (1.5%) • Monitor fringe count errors (via Measurement data analysis) • Lifetime limited items: Number of INT sweeps - depends very much on operational scenario - see updated MIPAS IOM; little margin • Cooler: • Monitor Cooler Vibrations (Compressor/Displacer acceleration and harmonics) • Monitor Temperature stability (stability flags) • Monitor warning anomaly flags (ICU anomaly counts) • Important: take cyclically RTT formats (twice per orbit)

  23. Required Long-term Observations (2) - Others • Statistics on source packet losses : • evaluation of history entries required • Evaluation of life limited items : • depending on operational scenario - see previous page • Optical throughput : • needs to be observed together with NESR evaluations to decide whether detector warm-up is required

  24. CONCLUSIONS • MIPAS functional and operational behaviour excellent • Characterisation data is as expected and very accurate • Operational measures for detected anomalies in place • Long-term observations required on mechanisms and on source packet losses • Documentation: MIPAS SODAP Report + CAL/VAL extension

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