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The MESSENGER Mission to Mercury

The MESSENGER Mission to Mercury. Nori Laslo Johns Hopkins University Applied Physics Laboratory. A NASA Discovery Mission. Why Mercury? MESSENGER – a NASA Discovery Mission MESSENGER Mission Objectives Mission Challenges Mission Timeline MESSENGER Payload Mercury Dual Imaging System

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The MESSENGER Mission to Mercury

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  1. The MESSENGER Mission to Mercury Nori Laslo Johns Hopkins University Applied Physics Laboratory A NASA Discovery Mission

  2. Why Mercury? • MESSENGER – a NASA Discovery Mission • MESSENGER Mission Objectives • Mission Challenges • Mission Timeline • MESSENGER Payload • Mercury Dual Imaging System • MESSENGER Load Building Process • MESSENGER data

  3. Why Mercury? • Highest orbital eccentricity in the solar system • Only planet with 3:2 spin orbit resonance • Smallest axial tilt: 0.01 degrees • Widest daily temperature range: 1100°F from day to night! (-300°F to 800°F) • Highest uncompressed density in the solar system • Largest ratio of core to size of planet: core is approximately 75% of Mercury’s radius, 42% of volume • Most inclined orbit: 7 degrees off of the ecliptic • Difficult to study with Earth-based telescopes: limited by proximity to Sun

  4. Why Mercury? • Some ground-based data: Arecibo, VLA, Goldstone Arecibo radar image of north polar deposits [Harmon et al., 2001].

  5. Why Mercury? • Mariner 10: 1974-1975 • First spacecraft to make use of “gravitational slingshot” • Mapped 45% of planet’s surface Mariner 10 image of Discovery Rupes

  6. MESSENGER: A NASA Discovery Mission • NASA Discovery Program • Program began in 1994 • Goal is to launch low-cost, scientifically focused missions • Mission proposals, each led by a Principal Investigator, undergo rigorous scientific and technical reviews • MESSENGER is the seventh mission chosen by NASA Discovery Program

  7. NEAR Mars Pathfinder Lunar Prospector Genesis Stardust CONTOUR MESSENGER Deep Impact Dawn Kepler • Near Earth Asteroid Rendezvous (NEAR) • Mars Pathfinder • Lunar Prospector • Stardust • Genesis • Comet Nucleus Tour (CONTOUR) • MESSENGER • Deep Impact • Dawn • Kepler

  8. Mission Objectives • MESSENGER – MErcury Surface Space ENvironment GEochemistry and Ranging • Six fundamental science questions to answer regarding the formation and evolution of Mercury (Solomon et al. 2001) • What planetary formational processes led to the planet’s high metal-to-silicate ratio? • What is Mercury’s geological history? • What are the nature and origin of Mercury’s magnetic field? • What are the structure and state of Mercury’s core? • What are the radar-reflective materials at Mercury’s poles? • What are the important volatile species and their sources and sinks on and near Mercury?

  9. Mission Challenges: Mass • Mass • Delta II 7925-H launch vehicle, largest available to a Discovery-class mission, limited total spacecraft mass to 1,107 kg • Much of the mass had to be fuel: 54% of total mass • Minimized dry mass: used lightweight titanium fuel tanks, carbon composite main structure, miniaturized instruments, integrated propulsion system into spacecraft structure • Minimized fuel required by selecting a complex trajectory utilizing gravity assists: maneuvers that use tug of a planet’s gravity to adjust speed or shape of spacecraft’s trajectory

  10. Mission Timeline

  11. Mission Timeline

  12. Mission Timeline

  13. Mission Timeline

  14. Mission Timeline

  15. Mission Timeline: Orbital Phase • Orbit Insertion: March 18th, 2011 • Requires ~33% of propellant • One orbit = 12 hours • Orbit is highly elliptical: periapsis altitude is 200km (124 mi), apoapsis altitude is 15,200 km (~9,420 mi) • Solar gravity slowly changes spacecraft’s orbit; corrective maneuvers required every 88 days

  16. Mission Challenges: Proximity to Sun • At such a small distance, actually falling toward the Sun; increased spacecraft speed means we actually need to break for orbital insertion • Solar radiation at Mercury 7-10 times that on Earth • Key component of thermal design: unique ceramic-cloth sunshade to protect instruments from harsh solar environment • Allowed for mostly standard electronics, components, and thermal blanketing materials

  17. Thermal Design

  18. Thermal Design

  19. Payload

  20. Mercury Dual Imaging System

  21. Mercury Dual Imaging System

  22. Mercury Dual Imaging System

  23. Mercury Dual Imaging System • Narrow-Angle Camera (NAC): • 1.5° Field of View • 1024x1024 pixels • Focal length = 550mm • 700-800 nm spectral range • Off-axis reflector:

  24. Mercury Dual Imaging System • Wide-Angle Camera (WAC): • 10.5° Field of View • 1024x1024 pixels • Focal length = 78 mm • Four-element refractor:

  25. Mercury Dual Imaging System • WAC also includes 12-color filter wheel; 395-1040 nm spectral range

  26. Mercury Dual Imaging System

  27. Load Building Process

  28. MESSENGER Data The results are in.....

  29. January 9, 2008 Distance: 1.7 million miles Narrow-Angle Camera Resolution: 70 km/pixel Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  30. January 13, 2008 Distance: 470,000 miles Narrow-Angle Camera Resolution: 20 km/pixel Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  31. January 14, 2008 Distance: 17,000 miles Wide-Angle Camera Filter: 750 nm Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  32. January 14, 2008 Distance: 3,600 miles Narrow-Angle Camera Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  33. January 14, 2008 Distance: 21,000 miles Narrow-Angle Camera Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  34. January 14, 2008 Distance: 3,600 miles Narrow-Angle Camera Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  35. January 14, 2008 Narrow-Angle Camera Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  36. January 14, 2008 Distance: 17,000 miles Wide-Angle Camera Filters: 1000, 700, 430 nm Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

  37. For more information… • Please visit: http://messenger.jhuapl.edu to see more data and animations (including the Earth and Venus flybys!), and for more information on the MESSENGER team and project. Questions? Email Nori at nori.laslo@jhuapl.edu.

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