Originally the term ‘space weather’ referred to the way in which “the variable conditions on the Sun can influence, throughout space and in the Earth’s magnetic field and upper atmosphere, the performance of space-borne and ground-based technological systems and endanger human life or health”(1). In the last years it has been extended to all the objects of the Solar Systems, becoming “Planetary Space Weather”.
The different aspects of the interactions induced by the Sun with the many objects of the Solar System should be studied in comparison with the Earth case, to help understanding the processes involved. In fact, possible comparative studies have already proven to be a powerful tool in understanding the different effects and interactions of space weather occurring around all the bodies of the Solar System.
In the present session, we welcome abstracts from all planets’ upstream solar wind activities and their relation to planetary space weather, including especially magnetized bodies (like Mercury, the Earth, Saturn and Jupiter) as well as comparisons with unmagnetized bodies (Mars and Venus).
Nevertheless, a special focus of this session will be on the planet Mercury whose environment in a few years will be the main goal of the dual ESA/JAXA mission BepiColombo. Bepicolombo will perform the first of six flybys at the end of 2021, and will begin its orbiting phase in 2026. One of the two spacecraft, the Japanese MIO, is especially designed to study the magnetospheric environment. Additional instrumentation onboard the European planetary spacecraft, orbiting closer to the planet, will measure the inner magnetosphere interactions with the exosphere and the surface.
In this frame, we welcome studies on:
• magnetosphere-ionosphere coupling dynamics (and auroras where present);
• the solar wind interaction with planets and moons (nb: for smaller bodies refer to session PS2.3 and for pure studies on unmagnetized bodies refer to session PS1.2)
• inter-comparisons of planetary environments;
• observations of space weather effects from space probes and Earth-based instrumentation;
• theoretical modeling and simulations, especially in view of measurement analysis and interpretation;
• potential impacts of space weathering on technological space systems.

(1) from US National Space Weather Plan (2000)