Mercury is unique among terrestrial planets because of its very high metal/silicate ratio. The NASA MESSENGER mission ended in 2015 and significantly advanced our understanding of the deep structure of the planet as well as our comprehension of Mercury’s volcanic history and crust formation. The European Space Agency (ESA) recently launched the BepiColombo mission in October 2018. The “Planet Mercury” issue summarizes the latest developments in light of MESSENGER data and perspectives for the BepiColombo mission on internal structures and surface processes, based on insights from geophysics, geochemistry, igneous and experimental petrology and volcanology.
