On 1 October, the ESA/JAXA BepiColombo mission captured its first views of its destination planet Mercury as it swooped past in a close gravity assist flyby at an altitude of 199km from the planet’s surface. Images from the spacecraft’s monitoring cameras, along with scientific data from a number of instruments, were collected during the encounter.

David Rothery of the UK’s Open University, who leads ESA’s Mercury Surface and Composition Working Group, said: “It was very exciting to see BepiColombo’s first images of Mercury, and to work out what we were seeing. It has made me even more enthusiastic to study the top quality science data that we should get when we are in orbit around Mercury, because this is a planet that we really do not yet fully understand.

“Although the cratered surface looks rather like Earth’s Moon at first sight, Mercury has a much different history. Once its main science mission begins, BepiColombo’s two science orbiters — ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter — will study all aspects of ‘mysterious Mercury’ — from its core to surface processes, magnetic field and exosphere — to better understand the origin and evolution of a planet close to its parent star.

For example, BepiColombo will map the surface of Mercury and analyse its composition to learn more about its formation. One theory is that it may have begun as a larger body that was then stripped of most of its rock by a giant impact. This left it with a relatively large iron core, where its magnetic field is generated, and only a thin rocky outer shell.”

BepiColombo’s main science mission will begin in early 2026. It is making use of nine planetary flybys in total: one at Earth, two at Venus, and six at Mercury, together with the spacecraft’s solar electric propulsion system, to help steer into Mercury orbit. Its next Mercury flyby will take place 23 June 2022.