1. Earth Observation, Navigation & Science Page 1 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk Report for WP 3300 WP 3300

2. Earth Observation, Navigation & Science Page 2 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Concepts – Space Segment Contents  Payload Aspects: Geostationary Instruments (Inputs from WP 3100) Low Earth Orbit Instruments (Inputs from WP 3200)  Mission Aspects: Alternative Mission Concepts - Options for LEO/MEO Constellations

3. Earth Observation, Navigation & Science Page 3 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk Report for WP 3300 WP 3300 Payload Aspects

4. Earth Observation, Navigation & Science Page 4 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Payload: Status/Overview  Based on the inputs of WP 3100 for geostationary and of WP 3200 for low earth orbit applications first assessments to show feasibility are performed.  Most of the defined mission requirements are reviewed and iterated with WP3100 and WP 3200.  The requirements are analysed by showing similarity to already existing investigations, mainly derived from the MTG, GeoTrope and Azechem studies.  For specific aspects first mathematical simulations are performed to outline e.g. radiometric instrument performance.  Budgets for mass, power and data rate are derived.  A first rating may be performed based on instrument mass and power budgets.

5. Earth Observation, Navigation & Science Page 5 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Geo Mission (inputs from WP 3100): Common Aspects  Compared to the Full Disk Coverage required for MTG (see GeoTROPE red) for CAPACITY the local coverage is limited to Europe (see GeoTROPE blue). Combined with the observation time of 1 hour this is a strong relaxation for Capacity instruments.

6. Earth Observation, Navigation & Science Page 6 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Geo Mission (inputs from WP 3100): UV-VIS-NIR-SWIR Spectrometer  Status Inputs from WP 3100 discussed and compared to MTG-UVS Relaxations to MTG requirements identified But optional design driving SWIR-channel required First sizing based on radiometric model performed  Design outline E-W single axis scanning imaging spectrometer Aperture diameter between 70 mm and 120 mm (SWIR) 4 dispersive spectrometers (UV, VIS, NIR and SWIR) Passive cooling of detectors  Interface Budgets Mass:150 kg Power:150 W Data Rate:5.5 Mbpsec

7. Earth Observation, Navigation & Science Page 7 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Geo Mission (inputs from WP 3100): IR Spectrometer  Status Inputs from WP 3100 discussed and compared to MTG-IRS Both enhancements and relaxations to MTG requirements identified Especially spectral resolution is design driving First sizing based on radiometric model performed  Design outline E/W and S/N dual axis scanning imaging spectrometer Fourier Transform Spectrometer (FTS) preferred MTG versus Capacity penalty score results in factor between 0.1 and 5.8 times MTG Active thermal cooling of detectors needed  Interface Budgets Mass:250 kg Power:250 W Data Rate:15 Mbpsec, FFT processing performed on board

8. Earth Observation, Navigation & Science Page 8 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 LEO Mission (inputs from WP 3200): Mission Options  Based on WP 3200 two different optional sun-synchronous LEO- missions are recommended For ozone layer and climate observations a LEO-Limb mission which is operated complementary to METOP with improved vertical resolution with - Infrared Sounder Option - or mm Sounder Option or a LEO-Nadir mission to improve the revisit time for air quality and the observation of diurnal variations for climate applications in an orbit complementary to parallel observations by other missions, e.g. with 11:30 or 15:30 local time with an - UV-VIS-NIR Sounder.

9. Earth Observation, Navigation & Science Page 9 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 LEO Mission (inputs from WP 3200): LEO- Limb Option: IR Sounder  Status Inputs from WP 3200 discussed and compared to AMIPAS AMIPAS matches very well into the CAPACITY specifications First sizing based on radiometric model as performed for AMIPAS  Design outline elevation single axis scanning imaging spectrometer Aperture diameter of 70 mm Michelson Interferometer Active cooling of detectors  Interface Budgets Mass:170 kg Power:180 W Data Rate:4 Mbps after lossless compression

10. Earth Observation, Navigation & Science Page 10 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 LEO Mission (inputs from WP 3200): LEO- Limb Option: mm Sounder  Status Inputs from WP 3200 reviewed and compared to MASTER First sizing based on MASTER  Design outline elevation single axis scanning antenna 2 m x 1 m offset Cassegrain antenna Signal down converted and amplified by a set of heteorodyne radiometers followed by spectrometers Active cooling of the frontend mixers  Interface Budgets Mass:280 kg Power:300 W Data Rate:120 kbps

11. Earth Observation, Navigation & Science Page 11 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 LEO Mission (inputs from WP 3200): LEO- Nadir Option: UV-VIS-NIR Sounder  Status Inputs from WP 3200 reviewed and compared to OMI and SCIAMACHY  Design outline Nadir imaging spectrometer Aperture diameter in the order of 30 mm 3 dispersive spectrometers is minimum Passive cooling of detectors  Interface Budgets Mass:65 - 200 kg Power:70 - 150 W Data Rate:TBD Mbpsec

12. Earth Observation, Navigation & Science Page 12 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Payload Conclusions  A first rating for the development effort of the instruments is based on instrument mass and power budgets.

13. Earth Observation, Navigation & Science Page 13 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk Report for WP 3300 WP 3300 Mission Aspects

14. Earth Observation, Navigation & Science Page 14 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects  One of the new driving observation requirements is the strongly reduced revisit time, e.g. between 0.5 and 2 hours for air quality observations.  If no full global coverage is required, e.g. over Europe only, geostationary observations are most efficient.  But additional observations are needed globally, so a scenario of two complementary missions, one geostationary and one low earth orbit, is baseline.  Optionally scenarios are constellation of 3 Satellites in a sun-synchronous low/medium earth orbit (LEO/MEO) to achieve full global coverage in a lower inclined low earth orbit (LEO) to improve the revisit time over Europe with reduced global coverage  Three mission scenarios are analyzed Sun-Synchronous Option 1 with c.a. 2 hours revisit time Sun-Synchronous Option 2 with c.a. 4 hours revisit time 125 deg inclined Orbit with c.a. 2 hours revisit time

15. Earth Observation, Navigation & Science Page 15 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: OMI Observation Geometry For the assessment of the local coverage the OMI observation geometry has been taken as reference  +/- 57 deg Nadir viewing angle  705 km altitude  => swath of 2600 km  => min. LOS/horizon angle of 21 deg

16. Earth Observation, Navigation & Science Page 16 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: Capacity Observation Geometry

17. Earth Observation, Navigation & Science Page 17 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: Radiation Environment Capacity 2 hours Capacity 4 hours Envisat 4mm shielding

18. Earth Observation, Navigation & Science Page 18 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km sun-synchronous orbit

19. Earth Observation, Navigation & Science Page 19 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km sun-synchronous orbit  Orbit altitude optimized for coverage of Europe (Latitude > 30 deg) with 2 successive orbit periods => 3.4 h revisit time

20. Earth Observation, Navigation & Science Page 20 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km sun-synchronous orbit

21. Earth Observation, Navigation & Science Page 21 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km low inclination orbit  Applying a low inclination orbit an local observation of Europe with an increased revisit frequency is feasible  These orbits are not sun-synchronous => variation of local time over orbit => strong variation of observation geometry over orbit => impacts on satellite design, especially power system

22. Earth Observation, Navigation & Science Page 22 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km low inclination orbit

23. Earth Observation, Navigation & Science Page 23 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km low inclination orbit  Orbit altitude optimized for coverage of Europe (Latitude > 30 deg) with each orbit period => 1.7 h revisit time

24. Earth Observation, Navigation & Science Page 24 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: 894 km low inclination orbit

25. Earth Observation, Navigation & Science Page 25 Capacity Final Presentation, 02.06.2005, Estec, Noordwijk WP 3300 Mission Aspects: Conclusions for Constellation  The revisit time can be strongly reduced by using a constellation of 3 satellites  The orbit selection is limited by the useful viewing angles for Nadir observations and the earth radiation environment  An orbit of 3090 km altitude allows a 2.55 hours revisit time in a sun-synchronous orbit, but for this altitude the total radiation dose can not be handled.  So a constellation of 3 satellites with ca. 894 km orbit altitudes is recommended Sun-synchronous option - to achieve global earth coverage with 2 successive orbits - with a revisit time of < 3.4 hours over Europe. Low inclination option - to achieve nearly global earth coverage - with a revisit time of < 1.8 hours over Europe.