The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission

We present a summary of the campaign of remote observations that supported the European Space Agency’s Rosetta mission. Telescopes across the globe (and in space) followed comet67P/Churyumov-Gerasimenko from before Rosetta’s arrival until nearly the end of mission in September 2016. These provided essential data for mission planning, large-scale context information for the comaand tails beyond the spacecraft, and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively ‘well behaved’ comet, typical of Jupiterfamily cometsand with activity patterns that repeat from orbit-to-orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet comachemistry and structure. This work is just beginning as the mission ends. In this paper we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies.