Exploring a Kinetic Impact Mission to Asteroid 2024 YR4

Asteroid 2024 YR4 is a Near-Earth Asteroid expected to pass through the Earth-Moon system in December 2032. While the risk of an Earth impact has been ruled out, the asteroid is still expected to pass close to the Moon, and even a lunar collision cannot be excluded. This early prediction offers a rare opportunity for a low-cost mission to investigate a small asteroid. We have recently begun exploring the feasibility of a kinetic impact mission targeting 2024 YR4. We propose sending a small spacecraft as a rideshare payload on a future lunar mission, and to keep it in lunar orbit until the asteroid approaches in 2032. The spacecraft would separate into two components, one designed to collide with the asteroid and the other equipped to observe the encounter from a safe distance. We focus on estimating the expected changes in YR4’s heliocentric orbit and spin state following the impact, and on evaluating whether these changes could be detected through follow-up observations. The mission would provide a valuable chance to observe a fast-spinning small asteroid at close range, along with 1998 KY26, a target of the Hayabusa2♯ mission. It would also contribute useful data for developing and validating kinetic impact techniques in the context of planetary defence.