This plot depicts measurements of the strength of Mercury's internal magnetic field measured on 10 successive MESSENGER orbits. Within 5 days, these observations tripled the number of measurements of the planetary field relative to the number available after all of the Mercury flybys by Mariner 10 and MESSENGER. Moreover, because of MESSENGER's orbit, the maximum magnitude of the measured field was greater than that seen during any of the spacecraft flybys. These observations are improving our knowledge of the geometry of Mercury's magnetic field, which will be key to understanding why Mercury has such a global field when the larger planets Mars and Venus do not.
On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft ever to orbit the planet Mercury
. The mission is currently in its commissioning phase, during which spacecraft and instrument performance are verified through a series of specially designed checkout activities. In the course of the one-year primary mission, the spacecraft's seven scientific instruments and radio science investigation
will unravel the history and evolution of the Solar System's innermost planet. Visit the Why Mercury?
section of this website to learn more about the science questions that the MESSENGER mission has set out to answer.
Credit: NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory
For information regarding the use of MESSENGER images, see the image use policy.