Lunar Ranging GroupLUNAR TeamGravitational Physics

Lunar PhysicsLunar Laser Ranging

12 April 2011Pasadena, California

Overall Schedule

• University of Califonia, San Diego– Tom Murphy– Via Telephone

• Goddard Space Flight Centrer– Stephen Merkowitz / Alix Preston– Via Telephone

• University of Maryland, College Park– Doug Currie

Decadal Survey Submissions

• Astronomy and AstroPhysics Decadal Survey– Gravitational and Particle Physics Panel Report– Many Excellent Comments on the Value of LLR

• Planetary Sciences Decadal Survey– Lunar Geophysical Network • Recommended for New Frontier Mission• Would Place Four Retroreflectors on the Moon

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Topics UMd• Talks• Decadal• Computer Simulations

– Result• Review Deployment & Roles• GLXP

– Candidates– Functions

• Deployment– Lander– Surface– Drilling

• Lifetime– Murphy– Sun Shade– Dust Bombardment

• Future Talks & Activities– Dust– ILRS

• Status and Suggestions• Ground Stations

– Tests at Frascati– NLSI

• Talk• Demonstration

Conference Proceedings • Currie, D. G., , the LLRRA-21/LSSO Team & the MoonLIGHT/INFN-LNF Team 2010, “A Lunar Laser Ranging RetroReflector Array for the 21 st Century” 40th

Lunar and Planetary Science Conference, The Woodlands, TX 1 • Currie, D. G., Zacny, K., 2010 Regolith Drilling for the Lunar Laser Ranging Retroreflector Array for the 21st Century, LUNAR Workshop, Cambridge MA

• Currie, D. G., Zacny, K., the LLRRA-21/LSSO Team & the MoonLIGHT/INFN-LNF Team 2010 ”A Lunar Laser Ranging RetroReflector Array for the 21 st Century” Lunar Exploration Analysis Group Washington DC.

• Dell'Agnello, S., Delle Monache, G. O., Currie, D. G., et. All, G., & McElfresh D. “The Moon as a test body for General Relativity and new gravitational theories” presented at the conference European Planetary Science Congress 2010 (ESPC2010) at the Angelicum Centre – Pontifical University of Saint Thomas Aquinas, Rome, Italy.

• Dell’Agnello, S. , Currie, D. G. , Delle MonacheG. O. , et al Cantone, C. Garattini, M. Martini, M. Intaglietta, N. Lops C. , March, R , Tauraso, R, Bellettini G. , Maiello, M , Berardi, S. , Porcelli, L.; "Next Generation Lunar Laser Ranging and its GNSS Applications"; IEEE Aerospace Conference, Big Sky (MT),

• Peron, R.; Bellettini, G.; Berardi, S.; Boni, A.; Cantone, C.; Coradini, A.; Currie, D. G.; Dell'Agnello, S.; Delle Monache, G. O.; , et al. “Advanced instrumentation for Solar System gravitational physics” EGU General Assembly 2010, held 2-7 May, 2010 in Vienna, Austria,

• Currie, D. G., Delle Monache & G. O. Dell’Agnello, S. 2010 “A Lunar Laser Retroreflector for the FOR the 21ST Century (LLRRA-21): Selenodesy, Science and Status” 2010 American Geophysical Union Fall Meeting San Francisco, CA

• Currie, D. G., Dell’Agnello, S. & Delle Monache, G. O. 2011 “LUNAR LASER RANGING: FLIGHT HARDWARE SIMULATION, TESTING AND STATUS”. Lunar and Planetary Science Conference, The Woodlands, TX , 

Talks, Colloquia and Public Presentations

• Talks at Scientific Conferences• • Currie, D. G., & the LLRRA-21 Teams 2011 “A LUNAR LASER RANGING RETRO-REFLECTOR ARRAY for the 21st CENTURY” 2nd Lunar Laser

Ranging Workshop, International Space Sciences Institute, Bern Switzerland

•  Currie, D. G., & The LLRRA-21 Teams 2010 “A LUNAR LASER RANGING RETRO-REFLECTOR ARRAY for the 21st CENTURY” LUNAR Workshop Boulder CO

• Currie, D. G., Dell’Agnello, S. & Delle Monache, G. O. 2010 A Lunar Laser Ranging Retroreflector Array for the 21st Century ISOT 2010 International Symposium on Optomechatronic Technologies, Toronto, Canada

• Currie, D. G., & the LLRRA-21 Teams 2011 “A LUNAR LASER RANGING RETRO-REFLECTOR ARRAY for the 21st CENTURY” 2nd Lunar Laser Ranging Workshop, International Space Sciences Institute, Bern Switzerland

• Dell’Agnello, S.; Currie, D. G.; Delle Monache, G. O.; Lops, C.; M. Martini 2010 “LLRRA21/MoonLIGHT: a 2nd Generation Lunar Laser Ranging Array for Precision Gravity Tests and Lunar Science Measurements” at the Conference Global Lunar Conference – Beijing, China.

• Ddd 31 May-3 June 2010 talk•  • Colloquia and Public Presentations• • Currie, D. G. 2011 2nd NLSI Commerce Virtual Lecture A LUNAR LASER RANGING RETROREFLECTOR FOR THE 21ST CENTURY•

Computer Simulations• Problems

– Commercial Software Issues– Computer Failures– 300 Million Beer’s Law Calculations for Each

• Computer simulation Objectives– End to End Simulation

• Technical Objectives– Selection of Thermal Coatings– Effects of Shorter Sun Shade

• GLXP Candidates for Size / Angular Tolerances

• Eclipse Effects– For LLRRA-21, not Apollo

Computer Simulations500 Time Steps Over a Lunation

• HeatLoad3D– IDL – University of Maryland– Evaluates Solar Heat Loads in CCR at ~ a Million Nodes

• Thermal Desktop– Commercial - Cullimorgan and Ring Technologies– Combine CCR Heat Loads with Solar Inputs to Temperature at 1733 Nodes

• TempToPhase– IDL – University of Maryland– Converts Temperatures from thermal Desktop into Phase Errors

• Code V– Commercial - – Combines Thermal Phase Errors with TIR Phases and Effect of Offset Angles

• Analysis– IDL – University of Maryland– Converts Far Field Diffraction Patterns into Useful Operational Results

Frascati Testing

• Thermal Vacuum Tests– Optical Table for Far Field Diffraction Pattern– InfraRed Camera for Temperature Meaurements– Optical Simulator for “Sun”– Thermal Sensors on CCR

• Images of Chamber and CCR Face

Different Deployment VersionsSingle Shot Range Accuracy

• Current Single Shot Accuracy is ~20 mm• If Mounted on Lander

– Thermal Expansion of Lander– Heat Flux from Lander– Single Shot Accuracy of 1-3 millimeters

• If a Surface Deployment– Thermal Expansion of Regolith– Heat Flux from Lander– Sub-Millimeter Single Shot Accuracy

• If an Anchored Deployment– Anchored at ~1 meter depth– Better than 100 micron Single Shot Accuracy

Google Lunar X Prize• Prize by Google Corporation for 30 M$

– Only Private Money for GLXP Objectives• Can Be Government Money

– For Other Objectives – Like LLRRA-21• Currently Working with:

– Lunar Express, Hai Li – Astrobotics David Gump– Moon Express Bob Richards– NextGreatLeap Michael Joyce– Penn State University Miles Smith– FREDNET Sean Casey

• Multiple Missions that May Be Successful– Achieve an Array of Retroreflectors

Deployment Lander

Surface Deployment

Anchored DeploymentAstrobotics & Honeybee

• Degradation of Laser Returns– Tom Murphy and APOLLO Station– Factor of 9.6 over 40 years

• Amelioration of Problem– Sun Shade

• Blocks Dust Deposition• Block Micrometeorite Bombardment

• But What is the Real Reason for Degradation?– For Micrometeorite Bombardment– Test at Horanyi’s Dust Accelerator

Lifetime of LLRRA-21

Signal Level for One LLRRA-21• Briefly

– LLRRA-21 Signal ~ Equal to Apollo 15 Array– Therefore Can Works with Sub-Meter Telescopes

• Will Need to Upgrade of Laser, Timing Electronics• McDonald at 0.67 meter Currently successfully Ranges to A15

– Long Life - Dust Issues Handled with SunShade

• More Precisely – IsoThermal– Station Angle LLRRA-21 Signal Return – Latitude Offsets w.r.t. A15– 45 Yes 78%– 45 No 58%– 00 Yes 88%– 00 No 71%

Future Objectives• Schedule: >> Driven by the Google Lunar X Prize Launch

– April/December 2013 i.e., Astrobotics– Need to Finalize the Design – Need to Attain Sufficient TRL to Obtain Funding i.e., T/V/O Test– Need to Fabricate/Test/Integrate Flight Hardware

• Simulations to Optimize Thermal Coatings– To Control Thermal Gradients and thus Signal – Optimize within Limits of Pracitical Coatings– Different Choices for Different GLXP Missions

• Interactions with GLXP Teams– Each has Different Physical & Organizational Structures– Therefore Each Requires Somewhat Different Thermal Design– Each Requires Different Emplacement Procedures

Future Talks & Activities• Evaluate Dust Bombardment

– Mihaly Horanyi – Dust Accelerator - Early May• International Laser Ranging Service Meeting – Late May

– Present Status of LLRRA-21 to Actual Ranging Groups– Collect Suggestions from Operators– Present What is Needed for Ground Stations for LLRRA-21

• Thermal/Vacuum/Optical Tests at Frascati – Early June – TRL 6.5 -> TRL 7.0

• NASA Lunar Science Institute – Mid July– Talk on LLRRA-21 Hardware and GLXP Mission Status– Report on Honeybee Grant on Pneumatic Drill for LLRRA-21– Demonstration of Pneumatic Drilling

• Probably Mounted on Astrobotic Lander