BepiColombo’s mission is to comprehensively study Mercury, including a characterization of its magnetic field, magnetosphere, and interior and surface structure. Launched on 20 October 2018, it is a joint mission between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA).
The ESA/JAXA BepiColombo mission will make its closest approach to Mercury on 8 January 2025. The spacecraft will fly just 295 km above Mercury’s surface. The closest approach is scheduled for 06:59 CET (05:59 UTC).
This will be the sixth and final flyby of the BepiColombo mission. During this, the spacecraft’s speed will be reduced. Also, its direction will change as it prepares to enter orbit around the tiny planet in late 2026.
While making this closest approach, the BepiColombo’s cameras and other instruments will investigate Mercury’s surface and surroundings.
As the official ESA blog mentioned, “BepiColombo will approach on the planet’s night side. Its monitoring cameras will get the most interesting views of Mercury’s surface as the spacecraft approaches the planet’s sunlit side, from about 07:06 CET, seven minutes after the closest approach. We expect to release the first images on 9 January, with other scientific data to follow.”
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Geraint Jones, ESA’s BepiColombo Project Scientist, said, “We can’t wait to see what BepiColombo will reveal during this sixth and final flyby of Mercury. While we’re still two years from the mission’s main science phase, we expect this encounter to provide us with beautiful images and important scientific insights into the least-explored terrestrial planet.”
BepiColombo will approach on the planet’s night side as Mercury’s sunlit side is scorching. The spacecraft will not receive direct sunlight in Mercury’s shadow for more than 23 minutes and will rely only on its batteries.
Ignacio Clerigo, BepiColombo’s Spacecraft Operations Manager, said, “This is the first time BepiColombo stays in the shadow of Mercury for so long. We have fully charged its batteries and raised the temperature of all components. From ESA’s mission control center, we will closely monitor all systems’ battery status and temperature during the flyby.”
“We’re preparing for this crucial moment of the flyby. One day before the eclipse, we’ll begin warming up the spacecraft and only stop the heating a few minutes before BepiColombo enters Mercury’s shadow. This strategy will help conserve battery power by preventing the spacecraft from having to use its heaters during the eclipse.”
The Italian Spring Accelerometer (ISA) will measure the accelerations experienced by the spacecraft as it is affected by Mercury’s gravity and changes in solar radiation and temperature when it enters and exits the planet’s shadow. ISA will also track any movements or vibrations caused by the spacecraft’s components, such as its solar arrays.
The authors said, “Excitingly, BepiColombo’s route takes it right over Mercury’s north pole. This allows the spacecraft to peer down into craters whose insides never get touched by the Sun. Despite temperatures reaching 450 °C on Mercury’s sunlit surface, the polar ‘permanent shadow regions’ are ice-cold. “
BepiColombo’s upcoming sixth flyby will take it on a unique path through Mercury’s magnetic and particle environment, exploring regions of the planet that have never been sampled. Some of these areas will not be visited during the mission’s main science phase.
The flyby route is particularly intriguing. It crosses the equator on Mercury’s night side, opposite the Sun, before flying over the planet’s north pole. In the darkness, the spacecraft will pass through areas where charged particles can flow from Mercury’s magnetic tail toward its surface. At the poles, the planet’s magnetic field lines funnel solar particles down to the surface in regions known as the cusps. BepiColombo will pass through the northern cusp during this flyby.
