Long wavelength folding on Mercury / Talk third bi-weekly / Vis Viva
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Sander van Oers became our first member on April 17th, 2013, when he gave this talk on his work on the geophysics of Mercury. His research was carried out during a placement at UCLA. https://twitter.com/SocietyVisViva https://www.facebook.com/SocietyVisViva http://www.visviva.nl ============== It shall be pointed out that our meetings are about more than just slides—they are about the interaction of our Fellows. Vis Viva offers a forum for the active discussion of space topics, and so our talks are lively get-together with a permanent conversation of the speaker and the audience. Since just slides cannot get this across, we kindly invite you to join one of our bi-weekly activities.
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Long wavelength folding on Mercury / Talk third bi-weekly / Vis Viva
- 1. 1 / 42
- 2. Outline 1 Why a Mission to Mercury? 2 The MESSENGER Mission 3 The MESSENGER Spacecraft 4 Long-Wavelength Folding 2 / 42
- 3. Why a Mission to Mercury? Last Visit: Mariner 10 in 1975 3 / 42
- 4. Six Key Outstanding Questions Why is Mercury so Dense? 4 / 42
- 5. Six Key Outstanding Questions What is the geologic history of Mercury? Credit: NASA/Johns Hopkins University 5 / 42
- 6. Six Key Outstanding Questions What is the nature of Mercury’s magnetic field? Credit: NASA/Johns Hopkins University 6 / 42
- 7. Six Key Outstanding Questions What is the structure of Mercury’s core? Credit: NASA/Johns Hopkins University 7 / 42
- 8. Six Key Outstanding Questions What are the unusual materials at Mercury’s poles? Credit: NASA/Johns Hopkins University 8 / 42
- 9. Six Key Outstanding Questions What volatiles are important at Mercury? Credit: NASA/Johns Hopkins University 9 / 42
- 10. The MESSENGER Mission Primary Mission Primary mission at Mercury: Orbit for one Earth year (equivalent to just over four Mercury years, or two Mercury solar days), collecting data on the composition and structure of Mercurys crust, its topography and geologic history, the nature of its thin atmosphere and active magnetosphere, and the makeup of its core and polar materials. 10 / 42
- 11. The MESSENGER Mission Quick Overview MESSENGER = MErcury Surface, Space ENvironment, GEochemistry and Ranging Cost Launch Date Launch Vehicle Flybys Arrival Status $446M August 3, 2004 Delta II 7925H EVVMMM March 2011 Extended Mission in Progress (!) 11 / 42
- 12. The MESSENGER Mission Interplanetary Trajectory Credit: NASA/Johns Hopkins University 12 / 42
- 13. The MESSENGER Mission Mercury Orbit Credit: NASA/Johns Hopkins University 13 / 42
- 14. The MESSENGER Mission Website - Q & A 14 / 42
- 15. The Spacecraft Quick Overview Size Mass Dry Mass Propellant Power Propulsion Large Maneuvers Small Maneuvers Instruments 1.42 m tall, 1.85 m wide and 1.27 m deep 1,107 kg 507.9 kg 599.4 kg 640 W One Bipropellant Thruster 16 Monopropellant Thrusters 7 15 / 42
- 16. The Spacecraft Challenges of a Mercury Orbiter Credit: NASA/Johns Hopkins University 16 / 42
- 17. The Spacecraft Assembly 17 / 42
- 18. The Spacecraft Laser Ranging at Interplanetary Distances Credit: NASA/Goddard Space Flight Center 18 / 42
- 19. The Spacecraft The Instruments Credit: NASA/Johns Hopkins University 19 / 42
- 20. The Spacecraft The Instruments: MLA Credit: NASA/Johns Hopkins University 20 / 42
- 21. Long-Wavelength Folding Observations Credit: NASA/Johns Hopkins University 21 / 42
- 22. Long-Wavelength Folding Observations Klimczak et al. (2012) 22 / 42
- 23. Long-Wavelength Folding Observations Credit: NASA/Johns Hopkins University 23 / 42
- 24. Long-Wavelength Folding A Theory Lithospheric Folding caused by Global Contraction due to Cooling Observed Amplitude: ∼ 2.5 km Observed Wavelength: ∼ 1200 km 24 / 42
- 26. Long-Wavelength Folding Result Perturbing Flow Fletcher and Hallet (1983) 26 / 42
- 27. Long-Wavelength Folding Folding on Earth: Basin and Range Province Image from Marli Miller, University of Oregon 27 / 42
- 29. Long-Wavelength Folding Linear Stability Analysis 1 Formulate the Basic Flow 2 Add a Small Disturbance 3 Substitute the Sum into the Governing Equations and Linearize 4 Formulate an Eigenvalue Problem 5 Solve the Eigenvalue Problem The flow is unstable if a solution grows in time. 29 / 42
- 30. Long-Wavelength Folding Growth Rate for one Wavelength 30 / 42
- 32. Long-Wavelength Folding Depth Brittle Layer Zuber et al. (2010) 32 / 42
- 33. Long-Wavelength Folding Different Creep Laws 33 / 42
- 34. Long-Wavelength Folding Initial Results For Mercury 34 / 42
- 36. Long-Wavelength Folding Problems-Wavelength Radius Mercurius ≈ 2440km, Wavelength = 1200 km Credit: NASA/Johns Hopkins University 36 / 42
- 38. Long-Wavelength Folding Multi-Layer Bassi and Bonnin (1988) 38 / 42
- 39. Long-Wavelength Folding Growth Rate for Multiple Layers 39 / 42
- 40. Long-Wavelength Folding Future Work 1 Solve Equations for a Spherical Body 2 Distinguish between Single or Mutli Layer Model 3 Incorporate Latest Findings on Mercury 40 / 42
- 41. Future for Mercury MESSENGER Credit: NASA/Johns Hopkins University 41 / 42
- 42. Future for Mercury BepiColombo 42 / 42