4:45 PM - 5:00 PM
[PPS02-06] Dynamic Regolith Exploration of Airless Small Bodies Through Low-Energy Multi-Impact Experiments
Keywords:Apophis, Impact experiments, Exploration
The physical and chemical properties of small bodies are crucial for advancing Solar System science, spacecraft exploration, planetary defense, and space resource utilization. Sample return missions provide a valuable means to obtain such information through detailed analyses of returned samples on Earth (e.g., Yokoyama et al. 2022; Lauretta, Connolly et al. 2024). Additionally, complementary information can be obtained through active/dynamic interactions between spacecraft and target bodies. Notable examples include the Deep Impact experiment on comet 9P/Tempel 1 (e.g., Sugita et al. 2005), the SCI (Small Carry-on Impactor) experiment on (162173) Ryugu by Hayabusa2 (e.g., Arakawa et al. 2020; Kadono et al. 2020), thruster operation of Hayabusa2 during ascent after sample collection (Morota et al. 2020; Tachibana et al. 2022), the TAG (Touch-And-Go) and thruster operation on (101955) Bennu by OSIRIS-REx (Lauretta et al. 2022), and the DART experiment on Dimorphos, a satellite of (65803) Didymos (e.g., Chang et al. 2023).
We here propose a new approach for the dynamic exploration of airless small bodies with multi-impact experiments. The mechanism for launch of the projectiles on the payload can take advantage of technological heritage from ALE's human-made shooting star satellites. Multi-impact experiments have the potential to reveal surface regolith cohesion, boulder strength, space weathering effects, and regional variations in these characteristics. Additionally, this technique could serve as a sample ejection mechanism for sample return missions without landing. It may also facilitate sublimation of surface ice for spectroscopic observation and/or sampling.
A Case of (99942) Apophis – We propose conducting low-energy multi-impact experiments on Sq-type asteroid Apophis after its Earth encounter in 2028, using a payload onboard a spacecraft performing a rendezvous with Apophis (ApophisExL; Nakamura-Messenger et al. 2025), to further study physical and material properties of the asteroid. The proposed impacts (up to 10–20 surface locations), with low kinetic energy (~50-100 J per projectile), are about 1/4-1/2 of that of Hayabusa2 sampler (Sawada et al. 2017) and are expected to make ~10-cm craters on regolith or chip off boulders. We also note that these low energy impacts will not alter the Apophis’s orbit. The proposed impact experiments will offer additional opportunities for dynamic exploration of Apophis, complementing the effect of Earth’s tidal forces and OSIRIS-APEX’s thruster experiment (DellaGiustina et al. 2023), and will provide unique scientific insights that enhance the overall value of all space missions to Apophis.
We here propose a new approach for the dynamic exploration of airless small bodies with multi-impact experiments. The mechanism for launch of the projectiles on the payload can take advantage of technological heritage from ALE's human-made shooting star satellites. Multi-impact experiments have the potential to reveal surface regolith cohesion, boulder strength, space weathering effects, and regional variations in these characteristics. Additionally, this technique could serve as a sample ejection mechanism for sample return missions without landing. It may also facilitate sublimation of surface ice for spectroscopic observation and/or sampling.
A Case of (99942) Apophis – We propose conducting low-energy multi-impact experiments on Sq-type asteroid Apophis after its Earth encounter in 2028, using a payload onboard a spacecraft performing a rendezvous with Apophis (ApophisExL; Nakamura-Messenger et al. 2025), to further study physical and material properties of the asteroid. The proposed impacts (up to 10–20 surface locations), with low kinetic energy (~50-100 J per projectile), are about 1/4-1/2 of that of Hayabusa2 sampler (Sawada et al. 2017) and are expected to make ~10-cm craters on regolith or chip off boulders. We also note that these low energy impacts will not alter the Apophis’s orbit. The proposed impact experiments will offer additional opportunities for dynamic exploration of Apophis, complementing the effect of Earth’s tidal forces and OSIRIS-APEX’s thruster experiment (DellaGiustina et al. 2023), and will provide unique scientific insights that enhance the overall value of all space missions to Apophis.