Potential Interaction of 99942 Apophis with the High Earth Orbit Population during the 2029 Close Approach

The asteroid 99942 Apophis will fly by the Earth closer than the geosynchronous (GEO) orbit on 2029 April 13, representing a unique opportunity for investigating a natural event in planetary sciences. Several space missions are planned to follow the Apophis flyby in situ. In particular, ESA’s RAMSES will rendezvous with the asteroid more than 1 month before the closest approach and will follow it for several months afterward. Although no risk of impact with the Earth is present, Apophis will pass in the vicinity of a number of artificial objects orbiting our planet. In the present paper, we propose a statistical analysis of the spatial distribution of active and abandoned objects in the vicinity of the GEO ring, building a synthetic representative population in order to assess the extent of possible interaction between Apophis (and any visiting spacecraft) and the simulated population for 2029. We argue that, while the probability of collision is likely extremely low, the chance of interaction cannot be completely ruled out. In particular, a possible impact with an abandoned debris could affect the rotational dynamics of the asteroid and jeopardize the success of any planned surface experiment, suggesting that an extensive characterization of the expected 2029 population is essential.