Near-Future Plans for IAWN Apophis Observing Campaigns

Near-Earth asteroid (NEA) 99942 Apophis is interesting because it will make an exceptionally close approach of the Earth in 2029 at a geocentric distance of 38,000 km making it the closest known flyby by a large NEA. The International Asteroid Warning Network (IAWN) conducts campaigns to test the operational readiness of the global coalition of observers, modelers, and decision makers to assess a potential NEO impact hazard.

In preparation for the 2029 close approach of Apophis, the IAWN is planning a two-phased campaign: a pre-encounter large-aperture and spacecraft phase in 2027 and 2028 that will be focused on NEO science, and a 2029 close approach phase focused on planetary defense with citizen science participants. Due to Apophis' relatively faint visual magnitude and short observing windows, the 2027 and 2028 opportunities will concentrate on refining its rotation state and gathering additional visible spectra. The IAWN will coordinate the large-aperture and space telescopes observing efforts. Observers will self-organize but IAWN will advocate for their telescope time, if requested. Scientific results from these efforts will be published independently by respective PIs with coordination from the IAWN. The 2029 close approach will be the primary focus for more direct IAWN efforts. Some of the campaign themes we are exploring include: a traditional IAWN campaign treating Apophis as a newly-discovered NEA, which would be similar to our 2021 Apophis campaign; enabling participation of small telescopes (<1 meter aperture) like those aligned with the proposed International Year of Planetary Defense; better coordination with Planetary Defense Conference exercise if there is one planned around Apophis in 2029; and integrating results from spacecraft rendezvous missions planned at or near the Apophis closest approach.