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

2. 2 The CLARREO Climate System DAC 1 Design DAC 5 Design DAC 2 /3 Design Updated Instruments Fields-of-View DAC 4 Design ? Matured RS Inter-calibration Operations Reduced costs ? ? Imposed Budget Profile Constraints

3. 3 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) Agenda

4. 4 Mission Design Strategy

5. 5 Guidelines for budget profile-driven mission design 1.Fly one spectrometer plus GNSS RO in 2017, and then both spectrometers and GNSS RO in 2020 2.Maintain parallel development of both spectrometers 3.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 Mission Design Strategy

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

8. 8 CLARREO-1CLARREO-2 ObservatoryLaunchObservatoryLaunch Option 1 2-Spectrometer (with only one) Falcon 92-SpectrometerFalcon 9 Option 21-SpectrometerTaurus XL2-SpectrometerFalcon 9 Option 31-SpectrometerTaurus XL 1-SpectrometerTaurus XL 1-SpectrometerTaurus XL 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. 9 Mission Concept for MCR

10. 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 S-Band Antenna X-Band Antenna GNSS POD Antenna GNSS Ram Antenna GNSS Wake Antenna Reflective Solar Instrument Suite Infrared Instrument Suite

11. 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. 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. 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. 14 DAC-5 Infrared Observatory Radio Occultation Antennae Choke Ring POD Antenna 4-panel Solar Array Infrared Instrument Assembly Star Tracker Thrusters

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

16. 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. 17 DAC-5 Reflected Solar Observatory Radio Occultation Antenna Choke Ring POD Antenna 4-panel Solar Array Reflected Solar Instrument Assembly (with 1-DOF Gimbal) Star Tracker Thrusters

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

19. 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 Case 1Case 2 Yaw angle (deg)-75-8 Roll angle (deg)55 Yaw set-up time (s)14046 Roll set-up time (s)108 Roll slew time (s)962

20. 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. 24 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 MCR Concept Summary

25. 25 Mission Concept Progression DAC 1 Design DAC 5 Design DAC 2 /3 Design Updated Instruments Fields-of-View DAC 4 Design Matured RS Inter-calibration Operations Reduced costs ? Imposed Budget Profile Constraints -OR- -AND- 2017 2020

26. 26 Phase A Mission Design Options and Trades

27. 27 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 Key Phase A Engineering Trades

28. 28 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 2 nd 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 New Data in Phase A

29. 29 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 Phase A Mission Options