This view of Mercury’s horizon was taken by the MESSENGER spacecraft in orbit around the planet. It was acquired looking from the shadows toward the sunlit side of the planet.A 120-km impact crater stands out near the center. The crater has several chains of secondary craters which gouge linear tracks radially away from it. While this crater does not appear to be of recent origin (its rays have faded), its secondary crater chains are more prominent than most similar craters.
Once per week, MESSENGER captures images of Mercury’s limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury’s shape and complement measurements of topography made by the spacecraft’s laser altimeter of Mercury’s northern hemisphere.
Image Credit: NASA