The BepiColombo spacecraft successfully separated its propulsion module on September 3, crossing a major threshold as it approaches Mercury after a 9.9-billion-kilometer journey. The joint mission led by the European Space Agency and the Japan Aerospace Exploration Agency confirmed the separation from ground control, setting up the craft to deploy two independent probes into orbit around the innermost planet.
Propulsion Module Separation Marks Final Approach
The separation occurred while the spacecraft was more than 200 million kilometers from Earth, following a complex trajectory through the inner solar system. BepiColombo launched to study Mercury’s surface, internal structure, and magnetic field, facing extreme gravitational forces and temperatures that exceed 430 degrees Celsius on the sunlit side and drop to -180 degrees Celsius on the night side. Because slowing down near the Sun requires massive amounts of braking fuel, the mission utilized nine gravity assist maneuvers—including one flyby of Earth, two of Venus, and six of Mercury—to manage its speed across its nearly 10-billion-kilometer path.
Dual Probes Prepare for Simultaneous Orbit
Following the propulsion module drop, BepiColombo will split into two distinct scientific orbiters. The Mercury Planetary Orbiter, managed by the European Space Agency, will map the planet’s surface and composition, while the Japan Aerospace Exploration Agency’s Mercury Magnetospheric Orbiter, known as Mio, will analyze the planet’s magnetic environment and thin atmosphere. Mio will operate in a higher elliptical polar orbit, while the Planetary Orbiter will descend to its final mapping altitude.
While the Mercury Planetary Orbiter is scheduled to reach its final operational orbit in March 2027, full science operations across both probes will not begin until April 2027. The delay accommodates essential calibration procedures, including the deployment of Mio’s vital sunshield. Researchers intend to use the gathered data to investigate why Mercury possesses an unusually large iron core, how ice survives inside permanently shadowed polar craters, and how terrestrial planets formed throughout the solar system.
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