On January 8, 2025, BepiColombo will perform its sixth flyby of Mercury. This is the final maneuver to move the spacecraft into a permanent orbit around the planet.
Long way to Mercury
The BepiColombo mission was launched in 2018. Its target is the closest planet to the Sun — Mercury. The vehicle consists of three components: the MTM flyby module, the European probe MPO and the Japanese MTO. After arriving at Mercury, the bundle will separate. MPO will study the surface and internal structure of the planet, while MTO will make measurements of its magnetic field.
Unfortunately, getting to Mercury is not easy. As it approaches the Sun, its powerful gravity accelerates the vehicle, preventing it from entering orbit around the planet. To extinguish this excess velocity, engineers developed a complex trajectory involving nine gravitational maneuvers — one at Earth, two at Venus, and six at Mercury. They are necessary for the braking of the BepiColombo.
To date, BepiColombo has performed eight of the nine maneuvers planned. The last, ninth maneuver will take place on January 8, 2025.
Sixth rendezvous with Mercury
During its final rendezvous, BepiColombo will approach Mercury at a minimum distance of 295 km. This capability will be used to photograph the planet, measure environmental parameters, and adjust instruments.
BepiColombo will approach the planet from the night side. The most interesting views are expected seven minutes after passing the minimum approach point, when the spacecraft reaches the illuminated part of Mercury. Selfie cameras attached to the BepiColombo body will be used to take photos. They are capable of taking black and white photos with a resolution of 1024×1024 pixels.
Curiously, the flight path of the vehicle passes directly over the north pole of Mercury. This will allow it to look at craters whose bottoms are never illuminated by the Sun. Data from the MESSENGER mission, as well as radar observations from Earth, indicate that it contains deposits of water ice. BepiColombo is expected to get some good views of Prokofiev, Kandinsky and Tolkien craters during the flyby. The spacecraft will also be able to photograph Mercury’s largest impact crater, known as Borealis Planitia, and the vast northern plains.
In addition to taking pictures, BepiColombo will measure Mercury’s magnetic field and study how it interacts with the solar wind stream. And ISA’s Italian accelerometer will collect data on how Mercury’s gravity, as well as temperature variations and radiation from the Sun, will affect the vehicle’s trajectory.
It is expected that the first images obtained during the flyby will be published by ESA as early as January 9. The Mercury encounter will reduce BepiColombo’s orbital velocity and direction of flight. This will allow the vehicle to enter a permanent orbit around the planet in November 2026.
According to ESA
