TROPOMI. Sentinel 5 Precursor instrument for air quality and climate observations. R. Voors Dutch Space. ICSO, 11 October 2012

Transcription

1 TROPOMI Sentinel 5 Precursor instrument for air quality and climate observations R. Voors Dutch Space ICSO, 11 October 2012

2 Sentinel 5 precursor and the TROPOMI payload Climate and Air quality Precursor mission for Sentinel 5 (see poster) Pre-development TROPOMI by Dutch Industries, Institutes and NSO The follow-on instrument after OMI (Ozone Monitoring Instrument) Gap filler mission for SCIAMACHY (Envisat), OMI (EOS-Aura) and the Sentinel 5 mission schedule driven program Funded by Dutch space agency (NSO) and ESA Launch planned for 2015; currently in critical design phase Dutch Space is the Instrument Prime KNMI is principal investigator and SRON is co-pi Spacecraft: AS250 platform provided by Astrium UK Ascending node 13.35h, 820km, sun-synchronous orbit. -2-

3 Wavelengths ranges and data products Main bands: UV-VIS NIR SWIR Resolution: 0.5 nm spectral 7 km spatial (nadir) daily global coverage -3-

4 S5p will enable daily coverage of the Earth with sub-city resolution -4-

5 TROPOMI: TROPOspheric Measuring Instrument Combining heritage: SCIAMACHY on ESA s Envisat Launched 2002 OMI on NASA s EOS-AURA Launched 2004 Sun backscatter spectrograph Wide angle staring nadir viewing with a 2600 km Swath UV-VIS-NIR-SWIR wavelengths TROPOMI 21-5-

6 UVN-DEM1 (Band ID1&2, UV1) Thermal Bus Unit (TBU) UVN-DEM2 (Band ID3&4, UV2/VIS) Radiant Cooler (RC) UVN-DEM3 (behind SWIR) (Band ID5&6, NIR) SWIR-OBM (Band ID7) UVN- OBM TSS Connector Bracket RF Ground plane (for harness) SWIR-FEE

7 TROPOMI Functional diagram -7-

8 Optics design; Telescope UVN and SWIR share freeform telescope (presented Wedn.) Large FOV; 108 FOV separation in flight direction primary mirror position of oversized entrance aperture Earth surface spectrometer slit scrambler aperture stop / pupil secondary mirror Smile [ ] UV and SWIR 7 NIR reflected SWIR 6 off slit Earth surface scrambler aperture stop / pupil secondary mirror Swath [ ] Polarisation scrambler primary mirror spectrometer slit -8-

9 The SWIR channel SWIR Spectrometer Slit Collimator Immersed Grating Imaging Lens Spectrometer Structure MLI Thermal Hardware Cooling Link Shrouds SWIR DEM FEE-ICU Harness Front End Electronics (FEE) FEE-Detector Flexi PCB Harness Detector Focal Plane Structure Cooling Link Thermal Hardware -9-

10 SWIR design overview -10-

11 SWIR optical design Immersed Grating Invar Button Mounting ear Baffle Flexure -11-

12 SWIR status: critical design stage Model Bread board Flexure Silicon/ Germanium Lens Glue Injection Hole Adhesive Pad -12-

13 Instrument Control Unit Receive and Condition S/C power Provide Command and Telemetry functions Science data management Temperature control Set and control Instrument heaters Monitor Instrument temperatures Control the mechanisms Control the light sources Sun diffuser calibration Telescope & Calibration Unit WLS + LED SLS UVN UV spectrograph + LED UVIS spectrograph + LED UVN-DEM UVN-DEM Instrument Control Unit (ICU) TM/TC Science data Located in Satellite Telescope NIR spectrograph + LED UVN-DEM PWR S/C Wide swath angle Earth viewing Multi-Stage Radiant Cooler SWIR Module SWIR spectrograph + LED Detector / FEE -13- TROPOMI FUNCTIONAL DIAGRAM

14 UVN detectors Wavelength UV-VIS-NIR Channels (3x): E2V Frame transfer CCD 750 ns line transfer 1024 x micron pixels Operating temperature ~-60 C NIMO mode to minimize RTS confirmed by radiation tests Swath -14-

15 SWIR detector + focal plane SWIR Channel ( nm): Sofradir CMOS Saturn detector MCT photo layer + ROIC 1000 x micron pixels Operated at ~-140 C Interface to Co- Registration Tube Detector PTFE Vent Tube The TROPOMI Front End Electronics (SRON) will provide the supply, bias and read out of the SOFRADIR SWIR detector. Warm Window Molybdenum Mount Aluminium Cold Finger Titanium Double Cone -15-

16 UVN Operational flexibility, agility Many measurement programming possibilities Exposure times, per detector Co-addition or dwell times, per ½ detector (band) Detector gain, per port ½detector ADC amplifier gain in 256 steps Swath binning factors Reduce pixels size at end of the swath -16-

17 Radiant Cooler (RC) + thermal design Radiant cooler Warm / Intermediate / Cold Stage Heatpipes (methane / ethane / ammonia) Deployable Earthshade Door Reflector Titanium + GFRP Support Frame Decontamination heaters Thermal design Active Temperature Control Ammonia, Ethane and Methane heat pipes Flexlinks Minimization of heat leaks Low conductive rigid detector mounting assemblies Multi-stage radiant cooler with a highly optimized geometry intermediate cold warm -17-

18 Signal-to-noise performance; EOL; 2% albedo -18-

19 Co-registration All wavelengths have to observe the same air mass / ground scene Within detectors / bands (intra-) and in between (inter-) Most critical are the UVIS NIR and SWIR NIR NIR has the O2A band for clouds characterization, used for air mass estimates other channels UV wavelengths less critical because they do not see clouds TROPOMI approach UVN-SWIR co-registration cannot be met by H/W alone; a S/W correction is needed Good stability over the orbits Good intra-band performance NIR band downlinked at 3.5 km swath resolution and 2.3 km flight direction -19-

20 Conclusion TROPOMI on Sentinel 5-precursor: a challenging programme State-of-the-art and world class leading instrument for air quality and climate studies Currently in critical design phase Many challenges: Schedule Large number of parties Leading edge technology [Courtesy of Astrium Ltd.] -20-

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