01-14-2025

Spacecraft captures high-def images of Mercury during very close flyby

Earth.com staff writer

A spacecraft named BepiColombo is currently zipping by planet Mercury, making a very close flyby and snapping incredible high-definition photos of our scorching hot solar system companion.

Mercury is the closest planet to the Sun and the smallest in our solar system, packing some pretty extreme features into its tiny frame. It zips around the Sun in just 88 Earth days, making its year the shortest of all the planets.

Despite being so close to the Sun, Mercury has a surprisingly large core made mostly of iron, which creates a strong magnetic field.

The surface is covered in craters, similar to our Moon, because it doesn’t have much of an atmosphere to protect it from meteoroids.

BepiColombo makes another close Mercury flyby

Mercury’s stark landscape received another visitor on January 8, 2025. The ESA/JAXA BepiColombo spacecraft, on its sixth flyby of the planet, swept just a few hundred miles above the north pole, capturing fresh glimpses of the cratered terrain.

Morning light soon bathed Mercury’s northern plains, revealing icy floors in areas that never see the Sun. Scientists hope these newly gathered snapshots will shed more light on the composition of this rocky body.

BepiColombo Monitoring camera 1 (M-CAM 1) took this photo at 07:12 CET, when the spacecraft was about 1427 km from the planet’s surface. The spacecraft’s closest approach of 295 km took place on the planet's night side at 06:59 CET. The image shows that large regions of Mercury's heavily cratered surface are smoothed over by lava from volcanic eruptions. This smoothing over is visible inside the 290 km-wide crater at the right of the image, called Mendelssohn. While its outer rim is still visible, it has been largely filled by the same smooth material that makes up the surrounding plains. Smaller, more recent impact craters dot the otherwise smooth crater. Credit: ESA/JAXA — *BepiColombo Monitoring camera 1 (M-CAM 1) took this photo at 07:12 CET, when the spacecraft was about 1427 km from the planet’s surface. Credit: ESA/JAXA*

The maneuver was the last in a series of gravity assists that will help BepiColombo enter orbit around Mercury in late 2026. At 06:59 CET, the craft skimmed just 295 miles above the surface on the planet’s night side.

Around seven minutes later, it passed above the pole and caught remarkable views of the sunlit north. Shortly after this milestone, Frank Budnik, BepiColombo Flight Dynamics Manager, underlined the success of the operation.

“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,” Budnik explained.

BepiColombo sees Mercury’s polar shadows

Scientists were excited to see evidence of chilly, forever-shadowed craters near the north pole. These cavities, including Prokofiev, Kandinsky, Tolkien, and Gordimer, are among the coldest places in the Solar System.

Despite Mercury’s proximity to the Sun, the crater floors remain dark and frigid. Some studies have suggested the presence of frozen water in these regions.

BepiColombo's M-CAM 1 took this long-exposure photograph of Mercury's north pole at 07:07 CET, when the spacecraft was about 787 km from the planet’s surface. The spacecraft’s closest approach of 295 km took place on the planet's night side at 06:59 CET. In this view, Mercury’s terminator, the boundary between day and night, divides the planet in two. Along the terminator, just to the left of the solar array, the sunlit rims of craters Prokofiev, Kandinsky, Tolkien and Gordimer can be seen, including some of their central peaks. Credit: ESA/JAXA — *BepiColombo’s M-CAM 1 took this long-exposure photograph of Mercury’s north pole at 07:07 CET, when the spacecraft was about 787 km from the planet’s surface.*

BepiColombo will investigate whether that possibility holds true once it settles into its final orbit.

Nearby stretches of volcanic plains called Borealis Planitia captured attention in one of the monitoring camera (M-CAM) images.

Extensive lava flows roughly 3.7 billion years ago paved this part of Mercury’s crust, burying older impact features like the Henri and Lismer craters. Wrinkles scattered across the plains likely formed as the interior cooled over time.

Volcanic memories and ancient impacts

Another close-up featured the Mendelssohn crater. Its outer rim is barely visible because past volcanic floods leveled the surface over countless millennia. Just a handful of smaller, younger craters break up the otherwise smooth ground.

Farther along, the Rustaveli crater appears to have undergone a similar process, joining a long list of aged and partially filled depressions.

The towering Caloris basin also makes a striking appearance. Spanning more than 900 miles, it is the largest known impact site on Mercury.

Lines stretching away from the basin mark the impact’s immense influence on the planet’s crust. A bright patch of lava seems to link with a trough below it, prompting questions about the direction of that molten flow.

Dark surface, bright surprises

Mercury is much darker than our Moon. Its surface reflects less light, which makes bright patches on fresh craters and volcanic deposits stand out.

Those more radiant regions often connect to younger events, such as volcanic eruptions or recent impacts.

A camera shot taken by M-CAM 2 highlights the Nathair Facula, an expansive fallout deposit from Mercury’s most powerful recorded volcanic explosion.

BepiColombo Spacecraft sees bright patch near Mercury's upper edge in this image is the Nathair Facula, the aftermath of the largest volcanic explosion on Mercury. At its centre is a volcanic vent of around 40 km across that has been the site of at least three major eruptions. The explosive volcanic deposit is at least 300 km in diameter. Credit: ESA/JAXA — *BepiColombo Spacecraft sees bright patch near Mercury’s upper edge in this image is the Nathair Facula, the aftermath of the largest volcanic explosion on Mercury. Credit: ESA/JAXA*

In the middle is a vent around 25 miles across. Scientists believe at least three large eruptions shaped this blast zone, which stretches about 186 miles across.

Nearby is the Fonteyn crater, formed a few hundred million years ago. Its youth becomes obvious from the pale debris that fans out in all directions.

What happens next?

European Space Agency (ESA) Director General Josef Aschbacher revealed the first image during his Annual Press Briefing on January 9, 2025.

Once BepiColombo starts orbiting Mercury, mission teams aim to use data from multiple instruments to zero in on how these features formed.

Analysts want to determine if water ice truly exists in the polar shadows and figure out whether the big lava flows advanced into Caloris basin or spread out of it.

The quest to understand Mercury’s makeup includes measuring old and new surface areas with advanced spectrometers.

Team members look forward to breaking down mineral clues about how the planet cooled and contracted over billions of years.

Final countdown to orbit

Observers see this recent pass as the final time BepiColombo’s monitoring cameras will capture such close-range shots. After all, the modules that house these cameras will separate from the main orbiters by late 2026.

The ESA’s Mercury Planetary Orbiter and the JAXA Mercury Magnetospheric Orbiter will then begin their core studies. That work will include collecting data on the planet’s magnetic field, geology, and surface chemistry.

“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,” explains Geraint Jones, BepiColombo’s Project Scientist at ESA.

“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,” Jones concluded.

Why Mercury and BepiColombo matter

Scientists look ahead to those orbits with great anticipation. They want to put to rest a few long-held questions about Mercury’s hidden polar ices, puzzling volcanic traces, and unexpectedly dark crust.

The spacecraft’s results should give researchers a better sense of how the planet formed and evolved. All eyes remain on the little world with big questions waiting to be answered.

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