WAC's Changing Footprint
The surface footprint of MESSENGER’s Wide Angle Camera (WAC) changes markedly as the spacecraft moves along its highly elliptical orbit . Here we see an image that includes Mercury's south pole and terminator, viewed from an altitude of 10,240 km (6363 miles). Approximately half of this image includes portions of Mercury’s surface that are not illuminated by the Sun. Compare the extent of this image to those taken from altitudes of 450 km (280 miles) and 14,895 km (9255 miles).
Date acquired: March 31, 2011
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington