NASA's Messenger probe is the first spacecraft to orbit the planet Mercury, and it sent back the first pictures taken from orbit on March 29, 2011. This view looks across Mercury's pockmarked surface toward the planet's horizon. Bright rays from Hokusai Crater can be seen running north to south.
Mercury isn't exactly the solar system's most colorful planet, but you can make out subtle shades in this first color image from Messenger. Major craters on Mercury are named after artists, authors, composers and other creative figures from history. The dominant crater in the picture is known as Debussy.
This chart shows you the names of notable features in the first picture ever taken by a spacecraft orbiting Mercury. The triangle indicates an area of the planet that had never been imaged before.
A narrow-angle image from NASA's Messenger orbiter focuses in on Debussy Crater, the bright feature at the top of the frame. The bright rays consist of material ejected by the massive impact that created Debussy, and extend for hundreds of miles.
This Messenger picture shows a heavily cratered region near Mercury's north pole, as seen from an altitude of about 280 miles. The region had never been imaged before. Previous up-close views of Mercury came from flybys, including the Mariner 10 mission in the 1970s and Messenger's pre-orbital encounters.
This picture of southern terrain on Mercury illustrates what Messenger chief scientist Sean Solomon means when he says "there are so many craters they start to obscure one another."
The crater near the bottom of this Messenger image is a beautiful example of a relatively small, simple, fresh impact feature on Mercury. The crater is nearly bowl-shaped, with just a small flat area in the center of its floor. The bright ejecta and rays are symmetrically distributed around the crater, indicating that the body that struck Mercury to form the crater approached on a path that was not highly inclined from the vertical.
Messenger's Wide Angle Camera is not your typical color camera. It is sensitive to 11 bands of color, in visible through near-infrared wavelengths. This WAC image shows several craters on Mercury, with bright rays from Hokusai Crater (to the north) crossing through the scene.
This Messenger image shows an area of Mercury that had not been previously imaged, in Mercury's north polar region. The smooth terrain is pockmarked by craters that cast long shadows. Understanding the interiors of such craters and any ices they may contain is one of the Messenger mission's main science goals.