Fts test definition summary
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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

FTS Test Definition Summary

Kaley Walker

Test Readiness Review

January 29, 2003


What needs to be done

What Needs to be Done

  • Performance testing of:

    • Passive cooler / detectors

    • Suntracker / co-registration

    • Imagers

    • Spectrometer (ILS, FOV etc.)


Passive cooler

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


Detector temperature

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


Detector non linearity

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


Operational cycling

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


Detector monitoring

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


Suntracker

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)


Co registration

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


Imager characterization

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)


Imager charaterization

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)


Gas cell measurements

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


Gas cell measurements1

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


Fts tests

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)


Limit in testing

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


Issues

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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