This is one of the earliest images of Mercury returned by the MESSENGER spacecraft.
It was taken in January 2008, when MESSENGER was about to embark upon a seven-year period of exploration and discovery of the innermost planet that would feature three flybys and four years of orbital operations. When this image was taken, our knowledge of Mercury came almost entirely from the flybys of the Mariner 10 spacecraft in the 1970s.
As the end of MESSENGER's long and fruitful journey looms, it's worth looking back at where we started in 2008. We didn't know to expect evidence of volatile loss across the planet, nor how much of Mercury was covered in volcanic plains, nor the amount by which the planet contracted as it cooled, nor even the true size of the mighty Caloris basin. We did not know what the entire planet's surface looked like.
Now, our understanding of Mercury's geological, geophysical, geochemical, atmospheric, and magnetospheric character has been changed forever -- the lasting legacy of the MESSENGER mission.
Date acquired: Janaury 09, 2008
Image Mission Elapsed Time (MET): 108364033
Image ID: 3807
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: ~68 km/pixel
Scale: Mercury has a diameter of 4,880 km (3,033 mi.)
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. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
For information regarding the use of images, see the MESSENGER image use policy.