Climate Absolute Radiance and Refractivity Observatory (CLARREO) Mission Design Options

1. Climate Absolute Radiance and Refractivity Observatory(CLARREO) Mission Design Options • CLARREO Formulation Team • July 9, 2010

2. The CLARREO Climate System ? ? DAC1Design DAC5Design DAC2 /3Design DAC4Design ? • Matured RSInter-calibration Operations • Reduced costs • ImposedBudget Profile Constraints • Updated Instruments Fields-of-View

3. Agenda Mission Design Options • Mission Design Strategy • Mission Concept for MCR • February MCR (DAC-4) Mission Concept • MCR (DAC-5) Mission Concept • Phase A Mission Design Options and Trades • Potential International / Interagency Collaboration (Steve Sandford)

4. Mission Design Strategy

5. Mission Design Strategy • Guidelines for budget profile-driven mission design • Fly one spectrometer plus GNSS RO in 2017, and then both spectrometers and GNSS RO in 2020 • Maintain parallel development of both spectrometers • Pursue spacecraft and launch vehicle cost reductions • Implementation Strategies • Build cost-effective flexibility into the mission architecture • Smaller, one-spectrometer observatories • Compatibility with multiple, smaller and lower cost launch vehicles • Take advantage of “block buys” to lower cost • Develop a common spacecraft bus for all observatories • Maintain a common launch vehicle interface

6. One-spectrometer Observatory Concept February MCR Two-spectrometer Observatory Smaller One-spectrometer Observatories with Common Spacecraft Bus

8. Mission Design Options for MCR • Option 3: • Requires only one spacecraft bus and one launch vehicle interface • Offers potential cost savings if the Taurus XL can be replaced by the Falcon 1e • Can take advantage of a Minotaur IV launch vehicle if it becomes available • Provides the most schedule flexibility, currently and in the future (sustainability)

9. Mission Concept for MCR

10. February MCR (DAC-4) Mission Design DAC-4 DESIGN FEATURES • Two identical observatories • Observatories launched individually on Minotaur IV+ class vehicles • Reflected solar instrument mounted on a 2-DOF gimbal • Observatory Budgets (CBE): • Mass: 804 kg • OA Power: 691 W • Observatories inserted into their final science orbits immediately after launch • Launch spacing 90 to 180 days GNSS POD Antenna S-Band Antenna Infrared Instrument Suite GNSS Wake Antenna GNSS Ram Antenna S-Band Antenna X-Band Antenna Reflective Solar Instrument Suite

11. Objectives of DAC-5 • Provide as much science value as possible while adhering to the budget profile and schedule from NASA HQ • Pursue cost savings that would enable both spectrometers to be developed in parallel • Use a common, smaller spacecraft bus • Be compatible with lower cost launch vehicles • Collaborate with international and interagency partners • Formulate a robust, technically feasible observatory reference design • The observatory reference design establishes feasibility for Pre-Phase A • The flight observatory configuration will be developed in partnership with a spacecraft vendor selected in Phase B • Discussions with spacecraft vendors have already begun: • Spacecraft RFI released in summer 2009 • Spacecraft concept studies conducted by the Applied Physics Laboratory (APL) in 2009 and 2010 • Visits to recently-awarded RSDO Rapid III vendors underway now

12. Falcon 1e Compatibility • To be compatible with a Falcon 1e launch vehicle (505 kg capability): • Configure observatory for a much smaller launch fairing • Implement observatory and architecture changes to reduce observatory CBE mass from 804 kg (DAC-4) to <388 kg (maintains 30% margin) • Reduce mass and power of all instruments • Assume uncontrolled post-mission de-orbit (propellant reduction) • Lower the spacecraft redundancy • Reduce 2-DOF reflected solar instrument gimbal to a 1-DOF gimbal Minotaur IV Fairing Falcon 1e Fairing

13. DAC-5 Infrared Observatory Infrared Observatory Summary • Compatible with Falcon 1e • Three-axis stabilized • Surrey reaction wheels • Magnetic torque rods • Redundant C&DH computers • S- and X-band communications • 126 Gbit solid-state recorder • Propulsion system • Orbit insertion correction • Orbit maintenance and collision avoidance • Observatory Mass: PRELIMINARY • CBE Mass: 361 kg • Mass Margin: 40% (NTE 505 kg) Falcon 1e Packaging

14. DAC-5 Infrared Observatory Choke RingPOD Antenna Star Tracker Infrared Instrument Assembly Radio Occultation Antennae 4-panel Solar Array Thrusters

15. DAC-5 Infrared Observatory Magnetic TorqueRods Reaction Wheel(1 of 4) C&DHComputer Power Distribution and Control Unit S-band Transceiver

16. DAC-5 Reflected Solar Observatory Reflected Solar Observatory Summary • Compatible with Falcon 1e • Three-axis stabilized • Surrey reaction wheels • Magnetic torque rods • Redundant C&DH computers • S- and X-band communications • 320 Gbit solid-state recorder • Propulsion system • Orbit insertion correction • Orbit maintenance and collision avoidance • Observatory Mass: PRELIMINARY • CBE Mass: 372 kg • Mass Margin: 36% (NTE 505 kg) Falcon 1e Packaging

17. DAC-5 Reflected Solar Observatory Choke RingPOD Antenna Star Tracker Radio Occultation Antenna Reflected Solar Instrument Assembly(with 1-DOF Gimbal) 4-panel Solar Array Thrusters

18. Single Axis Gimbal Concept Commercial Moog Type-5 LaRC InternalDesign Concept • DAC-5 Single-Axis Gimbal Concepts • CBE Mass: 12 kg • CBE Avg. Power: 17 W

19. RS Reference Inter-calibration Operations • Reference inter-calibrations conducted using a combination of: • Spacecraft yaw maneuvers • Gimbal roll maneuvers • ACS simulations for typical inter-calibration cases have verified performance

20. RS Calibration & Verification Operations • Proposed solar calibration approach: • The 1-DOF gimbal provides an annular field-of-regard (FOR) for the reflected solar instrument • During every orbit the sun will pass through this FOR • Just prior to the sun entering the FOR, the gimbal will roll the RS instrument’s FOV into the proper location • Relative orbital motion carries the sun through the FOV • The gimbal returns to nadir viewing • Repeat for successive orbits • A similar process is used for lunar verification • Additional constraints apply(CLARREO in umbra, angular constraints)

21. Every lunation doesn’t provide 9 lunar verification opportunities

24. MCR Concept Summary • CLARREO has formulated a mission concept that achieves the science objectives within the budget and schedule constraints • Still some remaining work to finalize the observatory MEL’s and the reflected solar instrument calibration operations • Cost savings opportunities look promising • A one-spectrometer observatory concept was developed that enables either an infrared observatory or a reflected solar observatory to be accommodated on a Falcon 1e launch vehicle • Implementing a common spacecraft bus for the infrared observatory and reflected solar observatory is feasible • The proposed mission concept with a common spacecraft bus makes the mission design insensitive, in the near-term, to which spectrometer is selected for launch in 2017 on CLARREO-1

25. Mission Concept Progression 2017 -OR- 2020 -AND- ? DAC1Design DAC5Design DAC2 /3Design DAC4Design • Updated Instruments Fields-of-View • Matured RSInter-calibration Operations • Reduced costs • ImposedBudget Profile Constraints

26. Phase A Mission Design Optionsand Trades

27. Key Phase A Engineering Trades • Radio occultation antenna maturation • Trade antenna mounting concepts to reduce multi-path and integrate other observatory functions • JPL is providing occultation antenna design and multi-path analysis support • Revisit solar array configuration (again) • Trade alternative concepts seeking to: • Simplify the array configuration • Reduce jitter • Reduce radio occultation multi-path potential • Maintain a fixed observatory c.g. • Included in APL task order • Continue reflected solar trades for reference inter-calibration, solar calibration, and lunar verification ops • 1-DOF vs. 2-DOF gimbal

28. New Data in Phase A • RSDO spacecraft vendor data • The Rapid III spacecraft contract was recently awarded • We are visiting each Rapid III vendor to gather data on the buses that are most compatible with the MCR mission concept, viable candidates include (among others): • Surrey Space Technologies SSTL-300 • Northrop Grumman Eagle-1 • Orbital LEOStar-2 • Currently planning to release a spacecraft RFI in the 2nd half of Phase A • Launch vehicles • NASA Launch Services contract to be awarded this year • Inaugural Falcon 1e launch planned for Spring 2011 • Minotaur IV and Falcon 9 had successful inaugural launches in 2010 • NASA budget updates • Updates on international and interagency collaborations

29. Phase A Mission Options • First priority is to get the second spectrometer on-orbit in 2017 • Current strategy is to realize enough cost savings to build the second spectrometer as an instrument of opportunity • Fall-back position could be to accelerate the second spectrometer to a launch earlier than 2020 • The one-spectrometer observatory mission concept enables this option • Another alternative is to launch CLARREO-1 on a Taurus XL or Minotaur IV, providing more mass capability to: • Re-institute the 2-DOF gimbal on the reflected solar observatory • Increase the lifetime of either observatory to 5-7 years • Implement a large, body-fixed solar array • But the budget-profile constraint still applies • CONCLUSION: Maintain flexibility and tight integration between science and mission engineering in Phase A to optimize the mission