Although most of the surface in this image had been seen by MESSENGER before this image was acquired, the area outlined in white, approximately 51 square km (20 square mi.) brought MESSENGER's image coverage of the innermost planet from 99.999993 percent to a full 100 percent. The journey from 45 percent coverage by the Mariner 10 spacecraft to 100 percent coverage has enabled a better understanding of the global processes that shaped Mercury's formation and evolution. Even so, only a tiny fraction of the planet has been observed at the highest resolution. Improving high-resolution coverage is an important aspect of MESSENGER's proposed second extended mission at Mercury.
Date acquired: December 30, 2012
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington