The BepiColombo Environment Radiation Monitor, BERM

The BepiColombo Environment Radiation Monitor (BERM) on board the European Space Agency’s Mercury Planetary Orbiter (MPO), is designed to measure the radiation environment encountered by BepiColombo. The instrument measures electrons with energies from ∼150keV to ∼10MeV, protons with energies from ∼1.5MeV to ∼100MeV, and heavy ions with Linear Energy Transfer from 1 to 50MeV⋅mg−1⋅cm2. BERM is operated continuously, being responsible for monitoring the radiation levels during all phases of the mission, including the cruise, the planetary flybys of Earth, Venus and Mercury, and the Hermean environment. In this paper, we describe the scientific objectives, instrument design and calibration, and the in-flight scientific performance of BERM. Moreover, we provide the first scientific results obtained by BERM during the BepiColombo flyby of Earth in April 2020, and after the impact of a solar energetic particle event during the cruise phase in May 2021. We also discuss the future plans of the instrument including synergies with other instruments on the BepiColombo and on other missions.