Mission profile and time periods used in this study. Lower panel: spacecraft distance to the comet (solid line) and the comet distance to the Sun (dashed line). The spacecraft orbited comet 67P from September 2014 until its mission ended on September 30, 2016. The spacecraft distance to the comet’s surface spanned from a thousand kilometers down to the surface, at the mission end on impact. During this period, the comet’s heliocentric distance varied between 3.8 and 1.24 au. Middle panel: the solar wind H⁺ density as seen by ICA. The color scale is logarithmic and increases for lighter colors. The solar wind ion cavity was observed for heliocentric distances below ~2 au. Upper panel: the selected mission segments (green), adding up to a total of 74 days of data.