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This animation shows a visualization of measurements of sodium-group ion flux (blue) and magnetic field (red) during MESSENGER's orbit on 14 April 2011. Sodium-group ions are measured throughout the entire magnetosphere, but they strongly peak near the magnetic cusps, where the magnetic protection of the planet is least effective. Measurements from more than 120 orbits were used to assemble a global picture of Mercury's three-dimensional exosphere.

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS is scheduled to acquire more than 75,000 images in support of MESSENGER's science goals.

Date Presented: September 29, 2011, at a NASA press briefing
Instrument: Fast Imaging Plasma Spectrometer (FIPS) portion of the Energetic Particle and Plasma Spectrometer (EPPS)

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.