BepiColombo's latest Mercury flyby unveils icy secrets

On 8th January 2025, the BepiColombo probe flew past Mercury for the sixth time, and the first images have just started to arrive on Earth. This is the first joint mission of ESA and the Japan Aerospace Exploration Agency (JAXA) to study the planet closest to the Sun. The spacecraft flew just a few hundred kilometres above the planet's north pole. The close-up images reveal likely icy craters, whose interiors remain in constant shadow, and vast sunlit northern plains.

BepiColombo flew just 295 kilometres above Mercury's surface during its cold and dark night, after which it passed over the north pole, continuing its trajectory near the illuminated northern side of the planet. ESA has shown the first images.

The main goal of M-CAM, the probe's monitoring cameras, was to capture Mercury's surface during the flyby, developing further research possibilities. This is the last opportunity for the M-CAM cameras to get such close-up shots of the planet before the module they're attached to separates, and the ESA and JAXA orbiters begin independent missions.

The observations made after passing through the planet's shadow revealed Mercury's surface in new detail. Shadowed craters at the north pole, such as those belonging to Prokofiev and Tolkien, remain some of the coldest places in the Solar System due to their persistent darkness despite being near the Sun. The presence of frozen water in these areas is suspected, presenting a puzzle that BepiColombo will continue to analyse during its mission.

Further views captured by M-CAM 1 include the extensive volcanic plains of Borealis Planitia. This terrain originates from vast lava eruptions about 3.7 billion years ago, and the flowing lava filled existing craters, giving the surface a distinctive appearance. The characteristic wrinkles formed as a result of further cooling of the planet's interior.

The images also revealed bright areas, such as Nathair Facula, where the largest volcanic eruption on Mercury occurred. The material ejected during this activity marks its youth compared to the rest of the planet's dark surface. BepiColombo continues to study the composition and age of these materials, providing insights into the planet's geological transformations.

The mission of the BepiColombo probe, launched on 20th October 2018, is a joint undertaking of ESA and JAXA and the first European expedition to Mercury. After arriving at Mercury at the end of 2026, the probe will separate, and both orbiters will manoeuvre into their dedicated polar orbits around the planet. Commencing scientific operations in early 2027, both orbiters will collect data during a nominal one-year mission, with a possible one-year extension.