Sunrise on Mercury

The joint European-Japanese BepiColombo mission captured this view of Mercury on 1 October 2021 as the spacecraft flew past the planet for a gravity assist manoeuvre. The image was taken at 23:40:27 UTC by the Mercury Transfer Module’s Monitoring Camera 3, when the spacecraft was 1183 km from Mercury. Closest approach of 199 km took place shortly before, at 23:34:41 UTC. This image is one of the closest acquired during the flyby.

The cameras provide black-and-white snapshots in 1024 x 1024 pixel resolution.  The high-gain antenna of the Mercury Planetary Orbiter and part of the body of the spacecraft are also visible, albeit overexposed. Due to the longer exposure time, ghosting is visible in the centre of the image, as well as some electronic noise. 

This dramatic picture of Mercury’s southern hemisphere shows sunrise on Astrolabe Rupes, a 250 km-long lobate scarp. Escarpments like this one are widespread across the planet and are proof of global contraction due to the extremely slow cooling of Mercury. Images showing long shadows like this one will help BepiColombo scientists investigate these features in detail to study Mercury’s tectonic history.  

Click here for annotated version.

The gravity assist manoeuvre was the first at Mercury and the fourth of nine flybys overall. During its seven-year cruise to the smallest and innermost planet of the Solar System, BepiColombo makes one flyby at Earth, two at Venus and six at Mercury to help steer on course for Mercury orbit in 2025. The Mercury Transfer Module carries two science orbiters: ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter. They will operate from complementary orbits to 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.