Overview of An Advanced Earth Science Mission Concept Study for a GLOBAL WIND OBSERVING SOUNDER A st

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Overview of An AdvancedEarth Science Mission
Concept Study for a GLOBAL WIND OBSERVING
SOUNDER A study carried out by GSFC and LaRC
for NASA HQ in cooperation with NOAAProgram
Scientist NASA/HQ Ramesh KakarProgram
Executive NASA/HQ Steve NeeckStudy Leads
GSFC/Jaya Bajpayee, Harry ShawScience Lead
GSFC/Bruce GentryLaRC Leads Michael Kavaya,
Upendra Singh
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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.

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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

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Science Working Group

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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
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GWOS Mission Requirements
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1.33
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GWOS Pre-Operational Measurement Requirements
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Mission Concept
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Hybrid Technology Sampling 1 of 3

• The coherent subsystem provides very accurate
  (lt1.5m/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.

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Hybrid Technology Sampling 2 of 3
GWOS with background aerosol mode
Coherent
Direct
GWOS with enhanced aerosol mode
Coherent
Direct
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Hybrid Technology Sampling 3 of 3
GWOS with background aerosol mode
Dual sampling with the coherent and direct
detection molecular Global Wind Observing Sounder
(GWOS)
GWOS with enhanced aerosol mode
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
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GWOS Instrument Concept
Features of the Instrument Concept
Star Tracker

• Utilizes Doppler lidar detection method
• Coherent (aerosol) detection _at_ 2 µm
• Direct (molecular) detection _at_ 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

Nadir
Telescope Modules (4)
Technology Development Needs

• 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

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GWOS Mission Concept
Observatory Concept
Dimensions in mm
S/C Bus
Observatory in Delta 2320-10 Fairing
Instrument
Features of the Mission 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 TTC
• Total Daily Data Volume 517 Gbits

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

• Continued development and utilization of
  Observing System Simulation Experiment tools and
  capabilities, and conducting OSSEs to examine
  sampling and impact questions such as
• Effects of clouds and aerosols
• Impact of lower stratospheric winds above storm
  systems
• Effects of along-track sampling frequency and
  accuracy
• Assessment of appropriate targeting strategies
  for various weather types
• 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.
• Collect data using existing/emerging air (e.g.
  IIPs) 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

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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.

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Tropospheric Wind Lidar Technology Experiment
(TWiLiTE) IIP
PI Bruce Gentry at GSFC
NASA WB57

• 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

TWiLiTE will demonstrate high altitude airborne
Doppler lidar tropospheric wind profiling for
research and as a precursor to space
TWiLiTE Doppler Lidar on WB57 pallet

• Develop the Fabry-Perot etalon optical head 1/06
• Develop the molecular Doppler receiver 4/06
• Develop the laser transmitter 6/07
• Develop the holographic telescope and
  scanner 8/07
• Complete system integration and ground 12/07
• testing
• Complete engineering test flights aboard 6/08
• WB-57 or Proteus aircraft

• Leverage investments by IRD, 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

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
TRLin 3 or 4 TRLexit 5
7/06
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Doppler Aerosol WiNd Lidar (DAWN)Compact,
Engineered, 2-Micron Coherent Doppler Wind Lidar
Prototype for Field and Airborne Validation
PI Dr Michael Kavaya, NASA Langley Research
Center
Objective
Laser Oscillator and Amplifier Heads

• 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

Planned Optical Bench Layout9.6 x 21.6 in
Key Milestones
Approach
Complete Preliminary Design of Transceiver 12/06
Demonstrate Prototype Breadboard Transmitter
3/07 Demonstrate Oscillator Performance 12/07 Com
plete Integration of Transceiver into
Testbed 8/08 with compact, ruggedized
packaging Complete LIDAR Testbed
Demonstration 12/08

• 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.

TRLin 4, TRLcurrent 4
Co-Investigators Dr. Jirong Yu, Dr. Grady Koch,
Dr. Upendra Singh NASA LaRC