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First Mercury Flyby January 14, 2008 Speaker: Marilyn Lindstrom Program Scientist, NASA Headquarters NASA Museum Alliance Embargoed until 1 pm 1/30/08. Mercury the Mystery Planet. Least known terrestrial planet Mariner 10 only spacecraft 3 flybys 1974-1975 Imaged just 45% of planet
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First Mercury Flyby January 14, 2008 Speaker: Marilyn Lindstrom Program Scientist, NASA Headquarters NASA Museum Alliance Embargoed until 1 pm 1/30/08 MESSENGER First Mercury Flyby
Mercury the Mystery Planet • Least known terrestrial planet • Mariner 10 only spacecraft • 3 flybys 1974-1975 • Imaged just 45% of planet • Large core • Small magnetic field MESSENGER First Mercury Flyby
MESSENGER the Mercury Orbiter • Principal Investigator: Sean Solomon, Carnegie Institution of Washington (CIW) • Project Manager: Peter BediniJohns Hopkins University Applied Physics Laboratory (APL) • Mission design, spacecraft development, and operations - APL • Instruments provided by APL, NASA GSFC, U. Colorado, U. Michigan MESSENGER First Mercury Flyby
Science Questions • Why is Mercury so dense? • What is the geologic history of Mercury? • What is the nature of Mercury’s magnetic field? MESSENGER First Mercury Flyby
Science Questions • What is the structure of Mercury’s core? • What are the unusual materials at Mercury’s poles? • What volatiles are important at Mercury? MESSENGER First Mercury Flyby
Science Instruments MDIS - dual imaging spectrometer, MASCS - UV-VIS-IR spectrometer, MLA - laser altimeter, MAG - magnetometer EPPS - energetic particles & plasma spectrometer, GRNS – gamma ray & neutron spectrometer, XRS - X-ray spectrometer radio science uses Doppler on communications tracking MESSENGER First Mercury Flyby
Spacecraft • Lightweight body • Large fuel tank (half the mass is fuel) • Several types of thrusters (bipropellant & hydrazine) • Ceramic fabric sunshade • Adjustable solar panels • Redundant systems (PSE,DPU) MESSENGER First Mercury Flyby
Trajectory 6 planetary flybys provide gravity assists to get into Mercury orbit (1 Earth, 2 Venus, 3 Mercury) We are about half-way there. 5 major propulsive maneuvers (and many minor ones) provide the thrust and guidance. MESSENGER First Mercury Flyby
Launch Launched August 3, 2004 aboard a three-stage Boeing Delta II rocket! MESSENGER First Mercury Flyby
Flyby Plan Messenger approached in nightime on the Mariner 10 side and departed in daytime on the newly seen MESSENGER side. MESSENGER First Mercury Flyby
MOC and SOC MESSENGER First Mercury Flyby
First Image Unseen Side First Look on Jan. 14, 2008 at Mercury’s Previously Unseen Side MESSENGER First Mercury Flyby
Geology - Craters Most crater ejects is closer to the rim than on the moon due to higher gravity. MESSENGER First Mercury Flyby
Geology – Basins Multi-ring basin MESSENGER First Mercury Flyby
Geology – Scarps Scarp Scarps (cliffs) can be hundreds of Km long; the scarp in this image is 200 Km (125 miles) wide. MESSENGER First Mercury Flyby
Geology - Poles South pole North pole The south pole is more heavily cratered than the north pole. MESSENGER First Mercury Flyby
Geology - History Craters Plains Secondary Craters Scarps MESSENGER First Mercury Flyby
Full Color Image MESSENGER First Mercury Flyby
Geochemistry The Mercury spectrum shows the degree to which different wavelengths of sunlight are absorbed or reflected by its surface materials. Dips in the spectrum indicate where sunlight shining on the surface is partially absorbed. MESSENGER First Mercury Flyby
Geophysics • Laser Altimetry (MLA) • Two craters are easily visible • Magnetic Field • Internal, dipolar MESSENGER First Mercury Flyby
Magnetosphere This plot shows the measured magnitude of the magnetic field of Mercury as MESSENGER executed its first flyby of that planet. MESSENGER’s Magnetometer (MAG) provided definitive identification of all boundaries of the Mercury magnetosphere system and revealed a less active system than was seen during the first Mariner 10 flyby. MESSENGER First Mercury Flyby
Atmosphere The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) found Sodium and Hydrogen tails that extend out 15,000 miles. MESSENGER First Mercury Flyby
Caloris Basin Caloris basin is bigger and more complex than we thought: Mariner 10 saw less than ¼ of this basin that is one of the largest in the solar system. The estimated diameter has increased to 1550 km. MESSENGER First Mercury Flyby
Caloris Basin Craters inside the basin include bright ray craters, a multi-ring basin, bright floored craters and dark halo craters. The surface on the interior is lighter color than that on the outside, indicating a difference in composition. MESSENGER First Mercury Flyby
Spider Radial Grabens Radial graben “Spider” near center of Caloris basin is unique on Mercury, unseen on Moon or Mars MESSENGER First Mercury Flyby
We’ll be back! The next flyby will occur October 6, 2008. Orbit insertion will occur March 18, 2011. MESSENGER First Mercury Flyby