Fifty-five hours from Mercury
Posted by Emily Lakdawalla
28-09-2009 9:52 CDT
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:Here's a cropped and enlarged version of the same, courtesy of Phil Stooke: What I think is cool about this image is that we are seeing substantially farther around the limb than we did in our previous view: Looking back up at the 55-hours-away image, the prominent bright crater in the north was imaged on approach to flyby 2. Then there's a cool dark-ring crater to the southwest of it. That dark-ring crater was only half-seen on the limb on approach to flyby 2; everything to the west (left) of it is brand-new territory, except possibly some terrain just at the edge of the disk that MESSENGER may have seen as it departed from flyby 2.
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!
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