ESA – Second Portion of Mercury

ESA – Second Portion of Mercury

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The ESA/JAXA BepiColombo mission has performed its second gravity assist of the planet Mercury, capturing new close-up images as it nears Mercury’s orbit in 2025.

The closest approach was at 09:44 UTC (11:44 CEST) on June 23, 2022, approximately 200 km above the planet’s surface. Images from the spacecraft’s three surveillance cameras (MCAMs), as well as science data from a number of instruments, were collected during the encounter. The MCAM images, which provide black and white snapshots at 1024 x 1024 pixel resolution, were uploaded during yesterday afternoon, and a selection is shown here (click on the images to expand the captions for details).

“We have completed our second of six Mercury flybys and will return this time next year for our third before arriving in orbit of Mercury in 2025,” said Emanuela Bordoni, BepiColombo’s deputy space operations manager. ESA.

Sunrise and shadows

Because the closest approach to BepiColombo was on the night side of the planet, the first images in which Mercury is illuminated were taken about five minutes after the close approach, at a distance of about 800 km. Images were taken for about 40 minutes after the close approach as the spacecraft moved away from the planet again.

As BepiColombo flew from the night side to the day side, the Sun apparently rose above the planet’s cratered surface, casting shadows along the terminator – the boundary between night and day – and highlighting the topography of the land dramatically.

Jack Wright, a member of the MCAM team and a researcher based at ESA’s European Space Astronomy Center (ESAC) in Madrid, helped plan the imaging sequence for the flyby. He said, “I hit the air when the first pictures dropped, and I got more and more excited after that. The images show beautiful details of Mercury, including one of my favorite craters, Heaney, which I suggested as a name a few years ago.

The search for volcanoes (annotated)

Heaney is a 125 km wide crater covered by smooth volcanic plains. It hosts a rare example of a candidate volcano on Mercury, which will be an important target for BepiColombo’s high-resolution imaging suite once in orbit.

Just minutes after the closest approach and with the Sun shining from above, Mercury’s greatest impact feature, the 1550 km wide Caloris Basin appeared for the first time, its highly reflective lavas on its ground making it stand out from the darker background. The volcanic lavas in and around Caloris are thought to postdate the formation of the basin itself by around one hundred million years, and measuring and understanding the compositional differences between these is an important goal for BepiColombo.

“The images from Mercury flyby 1 were good, but the images from flyby 2 are even better,” commented David Rothery of the Open University who leads ESA’s Mercury Surface and Composition Working Group and who is also a member of the MCAM team. “The images highlight many scientific goals we can achieve when BepiColombo enters orbit. I want to understand the volcanic and tectonic history of this amazing planet.

First sighting of Caloris (annotated)

BepiColombo will rely on data collected by NASA’s Messenger mission which orbited Mercury from 2011-2015. BepiColombo’s two science orbiters – ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter – will operate from complementary orbits to study all aspects of the mysterious Mercury, from its core to surface processes, magnetic field and of the exosphere, in order to better understand the origin and evolution of a planet close to its parent star.

Even though BepiColombo is currently in a ‘stacked’ cruise configuration, which means that many instruments cannot be fully exploited during brief overflights, they can still capture information about the magnetic, plasma and particulate environment around the spacecraft, from locations normally inaccessible during an orbital mission.

“Our instrument teams on both spacecraft have started receiving their science data and we are looking forward to sharing our first information from this flyby,” said Johannes Benkhoff, ESA’s BepiColombo project scientist. “It will be interesting to compare the data with what we collected during our first flyby and add to this unique data set as we progress towards our core mission.”

The main scientific mission of BepiColombo will start at the beginning of 2026. It is based on nine planetary flybys in total: one on Earth, two on Venus and six on Mercury, as well as the spacecraft’s solar electric propulsion system, to help navigate Mercury’s orbit. Its next flyby of Mercury will be on June 20, 2023.

For more information please contact:
ESA press relations

All MCAM images will be publicly available in the Planetary Science Archive next week. The impressions of the scientific instruments will be communicated in the coming weeks. Follow @bepicolombo on Twitter for further updates.

An image gallery with annotated and unannotated versions of images posted yesterday and today is provided below:

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