The Near-Earth Object (NEO) population represents a useful resource for human civilization, since their proximity makes them the most accessible bodies in our Solar System. However, they can pose a serious challenge to human civilization, as some of them can be potential impactors, as multiple craters on Earth were linked to mass extinction events. Until late 2022, humanity was not prepared for a potential impactor.

The DART/LICIACube mission was the first successful test for the kinetic impactor technique. The mission reached its target, the (65803) Didymos binary system, on 26 September 2022 and achieved all of its scientific goals, crashing into Dimorphos, Didymos' companion, and proving the feasibility of the kinetic impactor as mitigation method for planetary defence. Nowadays, (99942) Apophis is probably the most famous potential impactor ever known. It has been the first NEO to have been estimated with a non-zero chance of impact on Earth in 2029.

While subsequent observations have excluded such a catastrophic event, the occasion of Apophis' closest passage in 2029 will be a key occasion both for science advance and increasing scientific knowledge in the general public. Several space missions are therefore in the making to visit Apophis close to its Earth encounter in April 2029. The session will accept papers on the state of the art of planetary defense, with contributions from past successful missions as DART/LICIACube and a glance of the possible future missions like Hera and RAMSES.