Simulation of BepiColombo’s Gravity Investigation with Dynamical Mismodeling

The BepiColombo spacecraft, designed by ESA and JAXA, is currently in its cruise phase toward Mercury. Among the scientific investigations is the Mercury Orbiter Radio-science Experiment (MORE), which will exploit a multi-frequency microwave tracking system with an advanced Ka-band transponder to achieve its objectives pertaining to Mercury’s geodesy and fundamental physics. Leveraging precise measurements from this state-of-the-art radio tracking system, MORE is expected to provide new insights into Mercury’s interior, refining and expanding upon the findings of the MESSENGER mission. This work evaluates the performance of MORE’s gravity and rotation experiment, specifically assessing how BepiColombo’s improved radio tracking data can reduce uncertainties in the determination of Mercury’s gravity field, Love number k2, and rotational state. Differently from previous covariance analyses, this work includes errors in the dynamical model to assess the experiment’s performance under controlled mismodeling conditions. We present the results of a numerical simulation covering BepiColombo’s extended two-year orbital phase, with scientific operations set to begin in 2027.