1. Goddard Space Flight Center Overview of An Advanced Earth Science Mission Concept Study for a GLOBAL WIND OBSERVING SOUNDER A study carried out by GSFC and LaRC for NASA HQ in cooperation with NOAA Program Scientist: NASA/HQ Ramesh Kakar Program Executive: NASA/HQ Steve Neeck Study Leads: GSFC/Jaya Bajpayee, Harry Shaw Science Lead: GSFC/Bruce Gentry LaRC Leads: Michael Kavaya, Upendra Singh

2. Goddard Space Flight Center Reason for this Study  In August 2006, NASA HQ SMD/Earth Science Division requested that GSFC, JPL, and LaRC study a number of mission concepts, including a Global Winds Mission  The Mission Concepts identified were anticipated to be among those recommended in the NAS Decadal Survey released January 2007  The Mission Concept Studies provide HQ with advanced planning information to respond to the NAS recommendations and to help prepare the Science Mission Plan requested by Congress.

3. Goddard Space Flight Center Earth Science Advanced Mission Studies  The objective of the study was to assess the feasibility of Global Wind Mission and conduct a instrument and mission concept definition study.  The study results are not considered in any way a proposal and will be used by NASA HQ for internal planning purposes.  The study was directed by the NASA HQ Earth Science Division and the study team was tasked to define:  Science requirements  Instrument and mission concepts  Cost vs. performance  The deliverables for the study included:  A final report detailing the instrument and mission concepts, trades explored and life cycle mission costs and schedule including basis of estimate.  A follow-on task plan including recommended technology and research investments

4. Goddard Space Flight Center Science Working Group NameAffiliationResearch Area Scott BraunGSFCTropical dynamics; hurricanes Ron GelaroGSFCData assimilation and modeling Bruce GentryGSFCDirect Detection Doppler lidar Matt McGillGSFCRadiative transfer; Direct Doppler lidar Lars Peter RiishojgaardGSFCData assimilation and modeling David StarrGSFCClouds and mesoscale processes Yongxiang HuLaRCRadiative transfer and aerosols Michael KavayaLaRCCoherent Doppler lidar Upendra SinghLaRCCoherent Doppler lidar Bob AtlasNOAAData assimilation; modeling; hurricanes Wayman BakerNOAAOperational NWP Michael HardestyNOAAAtmospheric remote sensing; lidar Dave EmmittSWASignal processing; data utility; cloud effects

5. Goddard Space Flight Center GWOS Science Objectives Objectives – Improve understanding and prediction of atmospheric dynamics and global atmospheric transport – Improve understanding and prediction of global cycling of energy, water, aerosols, and chemicals How is this achieved? – Space based direct lidar measurements of vertical profiles of the horizontal wind field to provide a complete global 3-dimensional picture of the dynamical state, clouds permitting and over the oceans for the first time What are the benefits? – Improved parameterization of atmospheric processes in models – Advanced climate and atmospheric flow modeling – Better initial conditions for weather forecasting

6. Goddard Space Flight Center GWOS Mission Requirements 2 1.33

7. Goddard Space Flight Center GWOS Pre-Operational Measurement Requirements 1 2 3 4 m/s Velocity Accuracy 2 km 1.5 km 1 km 0.5 km 0 km Direct Detection Coherent Detection 24 km 21 km 18 km 16 km 12 km 10 km 6 km 4 km 14 km 8 km

8. Goddard Space Flight Center Mission Concept

9. Goddard Space Flight Center Hybrid Technology Sampling – 1 of 3  The coherent subsystem provides very accurate (<1.5m/s) observations when sufficient aerosols (and clouds) exist.  The direct detection (molecular) subsystem provides observations meeting the threshold requirements above 2km, clouds permitting.  When both sample the same volume, the most accurate observation is chosen for assimilation.  The combination of direct and coherent detection yields higher data utility than either system alone.

10. Goddard Space Flight Center GWOS with background aerosol mode GWOS with enhanced aerosol mode Coherent Direct Hybrid Technology Sampling – 2 of 3

11. Goddard Space Flight Center GWOS with background aerosol mode GWOS with enhanced aerosol mode Dual sampling with the coherent and direct detection molecular Global Wind Observing Sounder (GWOS) Green represents percentage of sampled volumes when coherent subsystem provides the most accurate LOS measurement; Yellow is for direct detection; Gray is when neither system provides an observation that meets data requirementsb Hybrid Technology Sampling – 3 of 3

12. Goddard Space Flight Center GWOS Instrument Concept  Utilizes Doppler lidar detection method  Coherent (aerosol) detection @ 2 µm  Direct (molecular) detection @ 355 nm  Direct channel laser based on GLAS;  Direct channel receiver based on TWiLiTE IIP  Coherent channel laser and receiver based on DAWN IIP  Telescopes are shared among all lasers  Pointing and knowledge requirements met with co- located star tracker and GPS Features of the Instrument Concept Technology Development Needs Telescope Modules (4) Nadir Star Tracker  Direct detection system req  uires 6 billion shots for mission lifetime (2 years)  Direct channel baseline is 3 lasers + 1 backup  Demonstration of reliable performance at higher or lower lifetimes will determine number of lasers for direct detection channel, impacting mission cost  Coherent detection system requires demonstration of the 316M shot lifetime in a fully conductively cooled laser  Both Lidar technologies require aircraft validation flights

13. Goddard Space Flight Center GWOS Mission Concept Features of the Mission Concept Instrument S/C Bus Observatory in Delta 2320-10 Fairing Observatory Concept Orbit: 400 km, circ, sun-sync, 6am – 6pm Selectively Redundant Design +/- 16 arcsec pointing knowledge (post-processed) X-band data downlink (150 Mbps); S-band TT&C Total Daily Data Volume517 Gbits Dimensions in mm

14. Goddard Space Flight Center Technology Maturity Roadmap 2 micron laser 1988 GWOS UAV Operation Aircraft Operation Compact Packaging 2005 Space Qualif. Pre-Launch Validation Packaged Lidar Ground Demo. 2007 Conductive Cooling Techn. 1999 Operational Autonomous Oper. Technol. 2008 (Direct) Space Qualif. Pre-Launch Validation 2-Micron Coherent Doppler Lidar Laser Risk Reduction Program IIP-2004 Projects Past Funding Diode Pump Technology 1993 Inj. Seeding Technology 1996 Autonomous Oper. Technol. 1 micron laser Compact Laser Packaging 2007 Compact Molecular Doppler Receiver 2007 Conductive Cooling Techn. Diode Pump Technology Inj. Seeding Technology High Energy Technology 1997 High Energy Laser Technology Lifetime Validation 0.355-Micron Direct Doppler Lidar

15. Goddard Space Flight Center Specific Recommended R & A Investments 1.Continued development and utilization of Observing System Simulation Experiment tools and capabilities, and conducting OSSE’s to examine sampling and impact questions such as: 1.Effects of clouds and aerosols 2.Impact of lower stratospheric winds above storm systems 3.Effects of along-track sampling frequency and accuracy 4.Assessment of appropriate targeting strategies for various weather types 2.Collect and analyze global and regional 3D statistics of clouds and aerosols and atmospheric two-way transmittance at both direct and coherent wavelengths using available observations. 3.Collect data using existing/emerging air (e.g. IIP’s) and spaceborne (e.g. ADM) Doppler lidar instrumentation and utilize it to support algorithm development for the molecular direct detection and aerosol coherent lidar wind systems, and especially the combined ‘hybrid’ Doppler lidar wind system

16. Goddard Space Flight Center Conclusion The Global Wind Observing Sounding (GWOS) mission will:  Fill a critical gap in our capability to globally measure wind profiles (speed, direction and structure).  Significantly improve skills in forecasting and in assessment of societal impacts, of high impact weather systems globally, particularly in - Mid-latitude storms including those affecting the continental USA - Hurricane track and intensity - Major dust storms in deserts and transport to other regions  Represent a break-through in instrument design in combining coherent and direct detection technologies for optimizing measurements of the entire troposphere from the boundary layer to the lower stratosphere  Advance technology transfer, and promote Research-to-Operation partnership between NASA and NOAA.

17. http://esto.nasa.gov Objective Key MilestonesApproach Develop the Fabry-Perot etalon optical head1/06 Develop the molecular Doppler receiver4/06 Develop the laser transmitter6/07 Develop the holographic telescope and scanner8/07 Complete system integration and ground12/07 testing Complete engineering test flights aboard6/08 WB-57 or Proteus aircraft Leverage investments by IR&D, SBIR, and ESTO to develop key technologies and subsystems: Space qualified Fabry-Perot etalon Molecular Doppler receiver Laser transmitter Conically scanning holographic transceiver Integrate the technologies and subsystems into an airborne Doppler wind lidar instrument Flight test TWiLiTE aboard WB-57 or Proteus aircraft PI: Bruce Gentry at GSFC 7/06 CoIs/Partners: Robert Atlas, Matt McGill, GSFC; Michael Hardesty, Alan Brewer, NOAA ETL; Tom Wilkerson, Space Dynamics Lab/Utah State University; Scott Lindermann, Michigan Aerospace Corp; Geary Schwemmer, Joe Marzouk, Sigma Space Corp Develop an airborne direct detection Doppler lidar wind instrument that will enable wind measurements from a nadir viewing, moving platform to simulate spaceborne measurement Obtain data on the effects of atmospheric constituents (clouds, aerosols) on instrument performance Advance the development of key technologies and subsystems for future spaceborne tropospheric wind- measurement systems Validate algorithms and methods of processing full tropospheric wind profiles from a moving platform Tropospheric Wind Lidar Technology Experiment (TWiLiTE) IIP TWiLiTE will demonstrate high altitude airborne Doppler lidar tropospheric wind profiling for research and as a precursor to space TRL in = 3 or 4 TRL exit = 5 NASA WB57 Laser HOE Telescope Doppler Receiver TWiLiTE Doppler Lidar on WB57 pallet

18. November / 2006 Co-Investigators: Dr. Jirong Yu, Dr. Grady Koch, Dr. Upendra Singh NASA LaRC Objective Key Milestones Approach Advancement of 2-micron laser technology towards a packaged, ruggedized system with a direct path to aircraft and space-flight systems Packaging and hardening of technologies developed under the Laser Risk Reduction Program Advance the technology readiness of 2-micron laser components to address the future development of Global Tropospheric Wind Missions PI: Dr Michael Kavaya, NASA Langley Research Center Doppler Aerosol WiNd Lidar (DAWN) Compact, Engineered, 2-Micron Coherent Doppler Wind Lidar Prototype for Field and Airborne Validation Laser Oscillator and Amplifier Heads Langley design and develop an advanced diode-pumped 2- micron laser head. Development of requirements and ruggedized design for a deployable laser system concept. System demonstration of wind measurement from the LaRC coherent Doppler wind LIDAR test bed. TRL in =4, TRL current =4 Complete Preliminary Design of Transceiver12/06 Demonstrate Prototype Breadboard Transmitter 3/07 Demonstrate Oscillator Performance12/07 Complete Integration of Transceiver into Testbed8/08 with compact, ruggedized packaging Complete LIDAR Testbed Demonstration12/08 Planned Optical Bench Layout 9.6 x 21.6 in