MERLIN: AN INTEGRATED PATH DIFFERENTIAL ABSORPTION (IPDA) LIDAR FOR GLOBAL METHANE REMOTE SENSING.

Transcription

1 MERLIN: AN INTEGRATED PATH DIFFERENTIAL ABSORPTION (IPDA) LIDAR FOR GLOBAL METHANE REMOTE SENSING. ICSO 2016 International Conference on Space Optics Markus Bode / markus.bode@airbus.com 19 October 2016 / Biarritz, France

2 MERLIN A French-German cooperation for global measurements of atmospheric Methane (CH 4 ) Scientific Goal A better understanding of the Global Methane (CH 4 ) Cycle and the nature of the processes which govern the exchange of methane between biosphere and atmosphere. Mission Objective Highly accurate space-borne measurements of the spatial and temporal variability of atmospheric CH 4 for determination of CH 4 fluxes (emissions) on the Earth s surface Measuring Method Integrated-Path Differential Absorption (IPDA) LIDAR in the near IR using pulsed laser transmitter and range-gated receiver in nadir-viewing mode (Image courtesy of CNES) 2

3 Determination of CH 4 fluxes by IPDA LIDAR Measurements and Inverse Modelling IPDA measurement of CH 4 Simulated concentrations using a priori CH 4 fluxes Forward simulation Inverse modelling Global distribution of CH 4 (Images courtesy of DLR) 3

4 MERLIN The Methane Remote Sensing LIDAR Mission Programmatic Background Political Frame Implemented as an Element of the French-German Agenda 2020 Initiated by the joint Franco-German Council of Ministers in February 2010 Executed by the French Space Agency (CNES) and the German Space Administration (DLR) Customer Responsibilities CNES: Satellite Operations, System, Launcher, S/C Bus (MYRIADE Evolutions) DLR: Integrated Path Differential Absorption (IPDA) LIDAR Instrument as single Payload Scientific Activities and Data Processing (Co-Principal Investigators) France: Laboratoire des Sciences du Climat et de l Environnement P. Bousquet Germany: Institute for Atmospheric Physics (IPA) of DLR G. Ehret Industrial Prime Contractors S/C Bus: Airbus Defence & Space (F) Payload: Airbus Defence & Space (D) 4

5 MERLIN The Methane Remote Sensing LIDAR Mission Mission Requirements Objectives Overall Scientific Goals Global mapping of atmospheric Methane content (CH 4 ), especially in key regions (Artic, Eurasia, Tropics) Identification of regional Methane sources and drains, in particular in inaccessible areas Verification of the Kyoto Protocol and follow-up agreements with respect to Methane Mission Parameters 506 km polar, sun-synchronous low earth orbit (6h or 18h LTAN) Daily global coverage Repeat cycle: 28 days Mission duration: 3 years Measurement Precision Primary Data Product: Column weighted, dry-air mixing ratio of CH 4 (XCH 4 ) Random Error: Threshold: 36 ppm Breakthrough: 18 ppb Systematic Error: Threshold: 3 ppm Breakthrough: 2 ppb 5

6 MERLIN The Methane Remote Sensing LIDAR Mission Space Segment Platform MYRIADE Evolutions Enhancement of the proven French micro-satellite platform MYRIADE Joint Development of CNES together with French Space Industry New Platform Product line for governmental and commercial applications Development and qualification in parallel with the MERLIN mission Features Satellite Mass: 400 kg Satellite Power: 416 Watts Platform Volume: mm 3 Mission Data: 160 MBits/s Mass Memory: 512 GBits Compatible with SOYUZ and VEGA internal position 6

7 MERLIN The Methane Remote Sensing LIDAR Mission Space Segment Payload IPDA Laser Instrument Pulsed laser transmitter and range-gated receiver in nadir viewing mode Transmitter based on Future Laser (FULAS) concept developed under ESA and DLR contracts Features Online Wavelength: nm Offline Wavelength: nm Pulse Energy: 9 mj Pulse Length: ns Repetition Rate:: 20 Hz (for double pulses) Ground Spot Size: ca. 90 m Tx, ca. 200 m Rx 7

8 MERLIN The Methane Remote Sensing LIDAR Mission Mechanical Design Payload Instrument Core Two separate telescopes for transmission (Tx) and reception (Rx) of the laser pulses Primary and secondary mirrors made of Zerodur Optical Bench of Carbon-fiber reinforced polymer (CFRP) for maximum stiffness and lowest CTE Features Proper operational alignment of the two telescopes with the two star trackers Implementation of active pointing device for LOS optimization Optimized thermal and thermo-elastic decoupling of the payload from the satellite platform Optimized for given volume requirements 8

9 MERLIN The Methane Remote Sensing LIDAR Mission Optical Design Payload Rx and Tx Telescopes Receiver telescope features an afocal design with a high magnification factor Design driver has been the compact envelope of the SOYUZ internal position, especially in launch direction, limiting the M1-M2 mirror distance Features Receiving and collimating optics designed for a strongly oversized FOV of 0.2 Rx telescope mainly diffraction limited for 1645 nm within the entire FOV Large FOV margin allows moderate manufacturing / alignment and stability tolerances for the telescope despite the highly compact design 9

10 MERLIN The Methane Remote Sensing LIDAR Mission Laser Transmitter Design Payload Laser Transmitter Single frequency high power Nd:YAG master oscillator power amplifier (MOPA) at 1064 nm Frequency conversion into 1645 nm using a optical parametric oscillator (OPO) Based on highly efficient Future Laser (FULAS) concept supported by ESA and DLR Space Agency Features Pressurized and hermetically sealed housing with an isostatic mounting I/F for accommodation. Hermetically sealed feedthroughs for electrical, optical, and thermal-hydraulic connectors Mini Loop Heat Pipes (LHP) directly attached to all heat sources inside the laser housing New mounting technologies applied, allowing precise, adhesive-free mounting of the optical components 10

11 MERLIN Payload Platform Panel 11

12 MERLIN Payload Isostatic Mounts 12

13 MERLIN Payload Radiator 13

14 MERLIN Payload Instrument Control Unit (ICU) 14

15 MERLIN Payload Frequency Reference Unit (FRU) 15

16 MERLIN Payload Laser Electronics (LAEU) 16

17 MERLIN Payload Harness Mounting Structures 17

18 MERLIN Payload Pockels-cell driver (LAEP) 18

19 MERLIN Payload LASer head (LAS) 19

20 MERLIN Payload Active Pointing Control (APC) 20

21 MERLIN Payload SIgnal Chain Unit (SICU) incl. OCL 21

22 MERLIN Payload Optical Bench with structural Elements 22

23 MERLIN Payload Rx Telescope Mirror M1 23

24 MERLIN Payload Tx Telescope and baffles 24

25 MERLIN Payload Final configuration (PL PDR) 25

26 MERLIN The Methane Remote Sensing LIDAR Mission Project Status and Next Steps Milestones MERLIN Programmatic Environment Official Announcement of German and French Ministries to continue MERLIN into Phase C/D on December 8 th 2015 at COP21 in Paris Cooperation Agreement for MERLIN Phase C/D between CNES and DLR Space Agency signed on September 14 th 2016 at the Federal Ministry for Economic Affairs and Energy in Berlin MERLIN Project (Payload & Platform) Project Phase B successfully performed Satellite Preliminary Design Review (SL PDR) successfully performed from July 2015 to October 2015 Payload Preliminary Design Review (PL PDR) successfully performed from October 2015 to April 2016 Project Phase C/D to be kicked off French industrial contract with Airbus Defence & Space SAS released by CNES in September 2016 Clarifications on German industrial contract successfully closed on October 14 th 2016, contract signature between Airbus DS GmbH and DLR Space Agency planned for end of October

27 MERLIN The Methane Remote Sensing LIDAR Mission Acknowledgements The authors would like to thank the whole bilateral MERLIN project team at the various sites of DLR, CNES, LSCE, Airbus Defence & Space in France & Germany, SpaceTech, Fraunhofer ILT, von Hoerner & Sulger, Safran Reosc, and Scisys for their continuous support and their fruitful cooperation in this challenging project. The German part of the MERLIN project is funded by the German Federal Ministry for Economic Affairs and Energy under DLR contract 50 EP Thank you for your attention! 27