Probing the Moon from Future Asteroid Impacts: A Review

Abstract

The Earth--Moon system has been experiencing impacts from asteroids and comets for billions of years. The Moon, as an airless body, has preserved a distinct record of these events in form of impact craters and ejecta deposits, offering valuable insights into the impact history and surface evolution of the Moon. However, the ancient impact relics can only provide limited information to the lunar interior structure, with an absence of the Moon's immediately dynamic response to the impact events. With human lunar exploration entering an era of sustained presence, e.g., lunar research station and human return, we propose a new concept to probe the lunar subsurface and interior by investigating the future asteroid impacts in real time. This can be achieved by integrating 1) ground- and space-based telescopes, 2) lunar-based seismometers and rovers, and 3) in-situ investigations around the impact sites. A promising opportunity arises with the possible lunar impact of the 60-m-sized asteroid 2024~YR4 in 2032 (impact probability $\sim$4.3\%), an event of once-in-ten-thousand-years rarity. Comprehensive observations of such events would greatly enhance our understanding of the Moon's structure and evolution, and have significant implications for the future lunar resource utilization and planetary defense missions.