  Context. The first long-term in-situ observation of the plasma environment in
the vicinity of a comet, as provided by the European Rosetta spacecraft. Aims.
Here we offer characterisation of the solar wind flow near
67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus
activity. We also aim to quantify and interpret the deflection and deceleration
of the flow expected from ionization of neutral cometary particles within the
undisturbed solar wind. Methods. We have analysed in situ ion and magnetic
field data and combined this with hybrid modeling of the interaction between
the solar wind and the comet atmosphere. Results. The solar wind deflection is
increasing with decreasing heliocentric distances, and exhibits very little
deceleration. This is seen both in observations and in modeled solar wind
protons. According to our model, energy and momentum are transferred from the
solar wind to the coma in a single region, centered on the nucleus, with a size
in the order of 1000 km. This interaction affects, over larger scales, the
downstream modeled solar wind flow. The energy gained by the cometary ions is a
small fraction of the energy available in the solar wind. Conclusions. The
deflection of the solar wind is the strongest and clearest signature of the
mass-loading for a small, low-activity comet, whereas there is little
deceleration of the solar wind.
