Emily Lakdawalla • Sep 28, 2009
Fifty-five hours from Mercury
Actually, at the time that I write this, MESSENGER is only about 32 hours and 400,000 kilometers from closest approach, but this photo was taken at 55 hours and 672,000 kilometers out:

NASA / JHUAPL / CIW
MESSENGER approaches for its third Mercury flyby
MESSENGER captured this photo of a crescent Mercury on September 25, 2009, on its way in to a September 29 flyby. This view of Mercury contains a small sliver of terrain never before observed by a spacecraft. MESSENGER will acquire much higher resolution views of this crescent as the distance between it and Mercury shrinks over the coming days. This version of the image has been enlarged by a factor of two.If this image is on Earth and squarely centered in the field of view, that would seem to indicate that all's well as MESSENGER approaches for its flyby, culminating tomorrow at 21:55 UTC (14:55 my time). Last night, I Tweeted about the latest mission update, which stated that by using solar sailing techniques they have targeted MESSENGER's flyby altitude to within 100 meters of the desired 228-kilometer-altitude aim point -- so they need no final trajectory correction maneuver.
Stay tuned for more!
Cosmic Shores Gala
The Planetary Society's Board of Directors cordially invites you to its 45th anniversary celebration at our Cosmic Shores Gala aboard the iconic Queen Mary in Long Beach, California. Please RSVP and purchase tickets to attend.
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