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of the innermost planet
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Trajectory Correction Maneuvers
August 24, 2004

Click on the image above for the MESSENGER Trajectory Correction Maneuver

Click on the image above for the MESSENGER Trajectory Correction Maneuver


The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft is shown in two views of the orientation required for its first trajectory correction maneuver (TCM-1), accomplished successfully on 24 August 2004. The dark gray (top view) or blue (bottom view) squares represent the back (shadowed) or front (sunlit) sides of the solar arrays, respectively. The large white (top view) or gray (bottom view) feature is the spacecraft's sunshade, which points away from the Sun when the spacecraft is near or beyond Earth's distance from the Sun. Colored arrows show the directions of Earth, the spacecraft's velocity with respect to the Sun, and the course correction velocity change (delta-V). The labels "xBody," "yBody," and "zBody" identify axis directions of the local spacecraft body-fixed coordinate system. A delta-V of about 18 meters per second (59 feet per second) corrected most of the inaccuracy associated with launch on 3 August 2004, thereby keeping the spacecraft on schedule for the next major mission event - Earth flyby on 2 August 2005. Mission controllers at The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, verified the start of the maneuver within 26 seconds, when the first signals indicating spacecraft thruster activity reached a tracking station in Madrid, Spain. The maneuver started at 5:00 pm Eastern Daylight Time and lasted just over 215 seconds.



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