BepiColombo

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The mission comprises two orbiters: the Mercury Planetary Orbiter (MPO), built and operated by ESA, and Mio (Mercury Magnetospheric Orbiter, MMO), built and operated by JAXA. Together the satellites will perform a comprehensive study of Mercury, including characterization of its magnetic field, magnetosphere, and both interior and surface structure. During the cruise phase to reach Mercury, the orbiters were in a stacked configuration with two additional components: the Mercury Transfer Module (MTM), which provided power and solar electric propulsion for the cruise, and the Magnetospheric Orbiter Sunshield and Interface (MOSIF), which protects Mio from the harsh solar radiation until it is deployed. MTM was jettisoned before orbit insertion at Mercury, whereas MOSIF will be detached from MPO after the Japanese orbiter is deployed. In 2017 the spacecraft's cost was estimated at €1.65 billion (US$1.86 billion). It was launched on an Ariane 5 rocket on 20 October 2018, with Mercury orbit insertion planned for December 2025, after a flyby of Earth, two flybys of Venus, and six flybys of Mercury. In 2024, due to a power-related anomaly limiting the thrust levels on its solar electric propulsion system, Mercury arrival was delayed to November 2026.