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FTS Test Definition Summary

FTS Test Definition Summary. Kaley Walker Test Readiness Review January 29, 2003. What Needs to be Done. Performance testing of: Passive cooler / detectors Suntracker / co-registration Imagers Spectrometer (ILS, FOV etc.). Passive Cooler.

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FTS Test Definition Summary

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  1. FTS Test Definition Summary Kaley Walker Test Readiness Review January 29, 2003

  2. What Needs to be Done • Performance testing of: • Passive cooler / detectors • Suntracker / co-registration • Imagers • Spectrometer (ILS, FOV etc.)

  3. Passive Cooler • Evaluate performance of passive cooler using He cooled target • Monitor detector and target temperatures • While cooling from room temperature • During instrument temperature transitions • Priority 1

  4. Detector Temperature • Measure while cooling detector – every 5 K from 110 → 70? K • High resolution spectra + N2O gas cell • Examine ILS vs. T and estimate NESR • Retrieve temperature and pressure • Low resolution spectra • Bandpass characteristics • Priority 1

  5. Detector Non-linearity • Measure while cooling detector – every 5 K from 110 → 70? K • Low resolution interferograms • At 1750, 2250, 2750 K (+ 3273 K from previous) • Ratio of centre burst to first side lobe to calculate • 5800 K point measured on orbit • Priority 1

  6. Operational Cycling • Measure at 90 K and lowest achieved T • Simulate normal operational power dissipation • Cycle between SCIENCE and SLEEP mode as for nominal occultation • Monitor detector temperature for any changes in cooling rate • Priority 3

  7. Detector Monitoring • InSb Instability (Priority 1) • Monitor channel for recurrence of problem • Contamination Monitoring (Priority 1) • Measure low resolution spectra every 12 hours using 2273 K HBB • Need criteria for when decontamination should be initiated

  8. 80 mrad + A. Setup suntracker mirror to point here. B. Move collimator mirror to move image here Suntracker • Sunscan – exercise mode using typical scan for MAESTRO calibration (Priority 1) • Stability – measure in closed loop with sunrise simulator (~50 s occultation) (Priority 2) • Pointing – characterize pointing over ±1.5 ° range using “leapfrog” technique (Priority 2)

  9. Co-registration • MAESTRO to VIS (Priority 2) • On bench with 532 nm laser source and in TVac with Xe lamp and pinhole • FTS to NIR (Priority 2) • Combined QI / HBB source and pinhole • NIR to VIS Registration (Priority 3) • relative orientation and pixel offset between arrays

  10. Imager Characterization • Flat Field Bench • Solar simulator to provides uniform illumination (Priority 2) • Flat Field TVac • Illuminate stepwise using QI source (Priority 2) • Non-linearity TVac • Stepwise illumination and vary attenuation (Priority 2)

  11. Imager Charaterization • Gain – characterize imager settings (Priority 2) • Dark Current – measure versus instrument temperature; perform prior to each test with imagers (Priority 2) • Cropping – test modes with sunrise simulator and attenuated source (Priority 3)

  12. Gas Cell Measurements • Combined – Measure NO2 and O3 with both FTS and MAESTRO (Priority 2) • compare retrieved temperature and pressure values • Additional – N2O measurements with FTS at instrument temperature plateaux (Priority 2) • Examine ILS vs. T and estimate NESR • Retrieve temperature and pressure

  13. Gas Cell Measurements • Occultation – Use suntracker to follow simulated occultation and measure FTS (and MAESTRO) spectra (Priority 3) • Have to step through occultation to allow for time for sufficient coadds • Suntracker pointing in closed-loop at fixed source • Somewhat unwieldy test that cannot provide “test as we fly” conditions

  14. FTS Tests • IR FOV – Move shutter stepwise across FOV and measure ZPD (Priority 2/3) • Non-uniform FOV Illumination – Use split attenuator to observe ILS effects (Priority 3) • Modulation Efficiency – To be done by Bomem (Priority 2)

  15. Limit in Testing • HBB cavity lifetime ~30-40 minutes at 3273 K and we only have 4 cavities • Almost all tests done at max. temperature • Priority 1 ~ 57 minutes • Priority 2 ~ 65 minutes • Priority 3 ~ 268 minutes • Majority of # 3 is Occultation – 223 minutes • without it we should have enough HBB lifetime to complete testing program

  16. Issues • Detector Decontamination • Need criteria for when this should be initiated • Occultation test • Significant drain on HBB lifetime • Recommend deleting from test schedule

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