Mercury images from final flyby of BepiColombo!
- The BepiColombo mission conducted its sixth and final flyby of Mercury on January 8, completing the last gravity assist before entering orbit around the planet in late 2026.
- The spacecraft flew just 183 miles (295 km) above Mercury, capturing close-up images of its surface.
- The Mercury images show permanently shadowed craters at Mercury’s north pole, some of the coldest places in the solar system, as well as lava plains, highlighting features of the planet’s relatively dark surface.
Flyby of Mercury
On January 9, 2025, ESA released new images of Mercury after the BepiColombo mission flew past Mercury for the sixth time on January 8, 2025. It successfully completed its final gravity assist maneuver needed to steer it into orbit around the planet in late 2026. The spacecraft flew above the planet’s north pole. Close-up images expose possibly icy craters whose floors are in permanent shadow, and the vast sunlit northern plains.
BepiColombo flew just 183 miles (295 kilometers) above Mercury’s surface on the planet’s cold, dark night side. Around seven minutes later, it passed directly over the Mercury’s north pole before getting clear views of the planet’s sunlit north.
This flyby also marks the last time that the mission’s M-CAMs – monitoring cameras – get up-close views of Mercury, as the spacecraft module they are attached to will separate from the mission’s two orbiters – ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter – before they enter orbit around Mercury in late 2026.
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!
Peering into Mercury’s darkest craters
After flying through Mercury’s shadow, BepiColombo’s monitoring camera 1 (M-CAM 1) got the first close views of Mercury’s surface. (See image above). Flying over the terminator – the boundary between day and night – the spacecraft got a unique opportunity to peer directly down into the forever-shadowed craters at planet’s north pole.
The rims of craters Prokofiev, Kandinsky, Tolkien and Gordimer cast permanent shadows on their floors. This makes these unlit craters some of the coldest places in the solar system, despite Mercury being the closest planet to the sun!
Excitingly, there is existing evidence that these dark craters contain frozen water. Whether there is really water on Mercury is one of the key Mercury mysteries that BepiColombo will investigate once it is in orbit around the planet.
To the left of Mercury’s north pole view lie the vast volcanic plains known as Borealis Planitia. These are Mercury’s largest expanse of smooth plains and that formed by the widespread eruption of runny lava 3.7 billion years ago.
This lava flooded existing craters, such as the Henri and Lismer craters highlighted in the image. The wrinkles in the surface that formed over billions of years following the solidification of the lava, probably in response to the planet contracting as its interior cooled down.
Mercury images show sunlit north
Another M-CAM 1 image, taken just five minutes after the first, shows that these plains extend over a large part of Mercury’s surface. Prominently visible is the Mendelssohn crater, whose outer rim is barely visible above its flooded interior. Just a handful of smaller, more recent impact craters dent the smooth surface.
Further out, but still within the Borealis Planitia, the Rustaveli crater suffered a similar fate.
On the bottom left of the image lies the massive Caloris basin, Mercury’s largest impact crater, which spans more than 900 miles (1500 kilometers). The impact that created this basin scarred Mercury’s surface up to thousands of miles away, as evidenced by the linear troughs radiating out from it.
Above a particularly large trough, a boomerang-shaped curve brightens the surface. This bright lava flow appears to connect to a deep trough below it. It appears similar in color to both the lava on the floor of the Caloris basin and the lava of Borealis Planitia further north. Yet another mystery that BepiColombo hopes to solve is which way this lava moved: into the Caloris basin, or out of it?
Lava and debris brighten Mercury’s surface
While M-CAM’s images might not always make it appear so, Mercury is a remarkably dark planet. At a first glance the cratered planet may resemble the moon, but its cratered surface only reflects about two-thirds as much light.
On this dark planet, younger features on the surface tend to appear brighter. Scientists don’t yet know what exactly Mercury is made of, but it is clear that material brought up from beneath the outer surface gradually becomes darker with age.
BepiColombo’s third image selected from this flyby, shows spectacular examples of the two things that bring bright material to the surface: volcanic activity and large impacts.
The bright patch near the planet’s upper edge in this image is the Nathair Facula, the aftermath of the largest volcanic explosion on Mercury. At its center is a volcanic vent of around 25 miles (40 kilometers) across that has been the site of at least three major eruptions. The explosive volcanic deposit is at least 186 miles (300 kilometers) in diameter.
And to the left lies the relatively young Fonteyn crater, which formed a mere 300 million years ago. Its youth is apparent from the brightness of the impact debris that radiates out from it.
Throughout its mission, several BepiColombo instruments will measure the composition of both old and new parts of the planet’s surface. This will teach us about what Mercury is made of, and how the planet formed.
Finishing in style
Frank Budnik, BepiColombo’s Flight Dynamics Manager, said:
This is the first time that we performed two flyby campaigns back-to-back. This flyby happens a bit more than a month after the previous one. Based on our preliminary assessment, everything proceeded smoothly and flawlessly.
Geraint Jones, BepiColombo’s Project Scientist at ESA, concluded:
BepiColombo’s main mission phase may only start two years from now, but all six of its flybys of Mercury have given us invaluable new information about the little-explored planet. In the next few weeks, the BepiColombo team will work hard to unravel as many of Mercury’s mysteries with the data from this flyby as we can.
About BepiColombo
After arrival at Mercury in late 2026, the spacecraft will separate and the two orbiters will maneuver to their dedicated polar orbits around the planet. Starting science operations in early 2027, both orbiters will gather data during a one-year nominal mission, with a possible one-year extension.
Bottom line: BepiColombo had its final flyby of Mercury on January 8, 2025. The spacecraft will eventually go into orbit around the closest planet to the sun. ESA released new Mercury images from this recent encounter.
Read more: Images from the 3rd Mercury flyby of BepiColombo!
The post Mercury images from final flyby of BepiColombo! first appeared on EarthSky.