BepiColombo

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to Mercury. It is designed to study the planet’s interior, surface, exosphere and magnetosphere, providing a comprehensive picture of Mercury’s geology, composition and space environment.

The mission architecture centers on the Mercury Transfer Module (MTM), which provides propulsion and carries two orbiters: the Mercury Planetary Orbiter (MPO) from ESA and the Mercury Magnetospheric Orbiter (MMO) from JAXA. The MTM relies on solar electric propulsion to transport the two orbiters to Mercury and to facilitate their separate insertions into orbit around the planet.

BepiColombo was launched on 20 October 2018 from the Guiana Space Centre in Kourou, France, aboard an Ariane 5 launcher. The flight path includes multiple gravity assists, notably from Earth and Venus, to shape the trajectory toward Mercury. Arrival at Mercury is planned for 2025–2026, with the MPO and MMO entering distinct, complementary orbits around the planet in a staged sequence.

Scientific objectives encompass determining Mercury’s interior structure and composition, mapping the planet’s topography and gravity field, assessing its rotational state and tectonics, and characterizing the exosphere and magnetosphere, including interactions with the solar wind. The mission carries instruments on both orbiters to observe surface mineralogy, thermal properties, and the magnetic and plasma environments.

BepiColombo represents a major international effort to advance knowledge of the Solar System’s innermost planet, offering detailed comparisons with other rocky worlds and contributing to broader planetary science.