Abstract: Confirmed small-body missions such as the MMX and HERA are set to explore Martian moons and the binary asteroid Didymos' moon Dimorphos, respectively. The dynamics around these small moons differ substantially from those of previously visited targets. Simplified models, such as the circular-restricted three-body problem, cannot yield accurate predictions for orbits and stability in real-world operations. The orbit of the small moon and its vicinity are significantly perturbed by the planet's oblateness and their relative positions. The unstable 3:1 resonance around a small moon further complicates orbit maintenance. This talk will introduce the "J2-ER3BP" model, which incorporates the mean J2 perturbation of the planet into the elliptic-restricted three-body problem, with the goal of minimizing perturbation resulting from model mismatches. The approach to computing bounded orbits in this model will be explained. Verification using a high-fidelity dynamical model and a realistic control environment indicates that the derived reference proximity orbits around Phobos and Dimorphos can be successfully maintained with minor cost.
Bio: Dr. Hongru Chen is an Assistant Professor at Kyushu University in Japan, having joined in 2021. She earned her Bachelor's degree from Northwestern Polytechnical University in China in 2010 and her Ph.D. from Kyushu University in 2015, both in aerospace engineering. She conducted her Ph.D. research at JAXA and once worked at the Chinese Academy of Sciences and Paris Observatory. She has contributed to JAXA and CNES’ interplanetary projects, such as PROCYON, DESTINY, and MMX. Her research interests include astrodynamics, mission and trajectory design, planetary geodesy, and upper atmosphere modeling. Dr. Chen has obtained several young investigator grants and has twice received the COSPAR Outstanding Paper Award for Young Scientists.
