BepiColombo Mercury Orbital Insertion

BepiColombo, the joint ESA-JAXA mission to Mercury, is scheduled to achieve Mercury orbital insertion on November 21, 2026 — 11 months later than originally planned due to a thruster anomaly discovered in September 2024 that required revised trajectory planning. The delay does not affect the mission's scientific objectives. BepiColombo launched on October 20, 2018, and has spent 7.5 years navigating the gravitational complexities of the inner Solar System, executing flybys of Earth, Venus (twice), and Mercury (six times) to shed velocity and fall into a stable Mercury orbit. The spacecraft configuration is unique in spaceflight history. Three distinct modules travel together: the Mercury Transfer Module (MTM) providing propulsion and power during transit, the Mercury Planetary Orbiter (MPO, built by ESA) designed for detailed surface and exosphere science, and the Mercury Magnetospheric Orbiter (Mio, built by JAXA) focused on the planet's anomalously large and active magnetic field. Once the MTM is jettisoned at arrival, the MPO and Mio will separate into independent elliptical orbits — two observatories working in concert around a single planet. Mercury is the least-explored terrestrial planet. NASA's MESSENGER spacecraft, which orbited Mercury from 2011 to 2015, revealed a world with unexpected volatile abundances, a complex crater history, and a magnetic field that punches well above its weight for a body its size. BepiColombo's more capable instrument suite — including the MERTIS mid-infrared spectrometer, the MIXS X-ray spectrometer, and JAXA's PWI plasma wave instrument — will probe these mysteries in far greater detail. Understanding Mercury is essential for testing models of planetary formation in the innermost zone of protoplanetary discs, with direct implications for understanding exoplanetary systems elsewhere in the galaxy.