The BepiColombo spacecraft has jettisoned its propulsion module as it prepares to enter orbit around Mercury in November.

The BepiColombo mission, a joint effort led by the European Space Agency with contributions from Japan and the United States, has reached a critical milestone in its eight-year voyage to Mercury. On Thursday, the spacecraft successfully jettisoned its Mercury Transfer Module, a necessary step before it attempts to enter orbit around the planet on November 21. The mission, which has traveled over 6 billion miles, aims to study Mercury using two separate orbiters.

Spacecraft separation and arrival

BepiColombo consists of three stacked components: the Mercury Transfer Module, the European-built Mercury Planetary Orbiter, and Japan’s Mercury Magnetospheric Orbiter, known as Mio. The transfer module provided power and propulsion during the cruise but was discarded to allow the remaining orbiters to function independently. The separation occurred 39 million miles from the Sun, a maneuver described by mission officials as high-risk due to the extreme solar radiation and heat. Following the separation, telemetry confirmed that the Mercury Planetary Orbiter’s solar arrays are generating power and recharging batteries. The two remaining orbiters are scheduled to release from one another in December after reaching their initial orbit, with routine scientific observations expected to begin in April 2026.

Mission goals and scientific objectives

The mission is designed to provide high-resolution mapping and study the planet's surface, magnetic fields, plasma, and dust. While the European orbiter will focus on the surface, the Japanese orbiter will operate in a higher orbit to monitor the environment. Scientists hope to investigate the composition of Mercury, including the potential presence of water ice in crater floors at the poles, and better understand the impact of solar wind on the planet.