BepiColombo says hello to Mercury and snaps its first pictures of planet

4 Oct 2021


The joint European-Japanese mission is completing one of nine gravity assists and will finally arrive in Mercury’s orbit in 2025.

Joint European-Japanese mission BepiColombo captured its first images of Mercury on Friday (1 October).

The mission, which is named after Italian scientist Giuseppe ‘Bepi’ Colombo, is a joint initiative of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). It launched from ESA’s spaceport in French Guiana in 2018.

The closest approach to Mercury by BepiColombo took place at around midnight Irish time on Friday at an altitude of 199km from the planet’s surface, during a flyby that spacecraft operations manager Elsa Montagnon described as “flawless”.

“It’s incredible to finally see our target planet,” she added.

Though it is the mission’s first flyby, BepiColombo is just visiting for now. This is one of nine gravity-assist manoeuvres the spacecraft is making during its trip: one at Earth, two at Venus and six at Mercury itself. It will finally achieve orbital insertion around the planet in December 2025, all going to plan.

The images were taken by monitoring cameras on the Mercury Transfer Module, and are positioned to also include part of the spacecraft itself, including its magnetometer boom and antennas.

ESA described the photography conditions as “not ideal”, as BepiColombo arrived on the dark side of the planet, so the closest images were captured at about 1,000km from the surface.

“It was an incredible feeling seeing these almost-live pictures of Mercury,” said Valentina Galluzzi, co-investigator on the mission’s SIMBIO-SYS imaging system.

“It really made me happy meeting the planet I have been studying since the very first years of my research career, and I am eager to work on new Mercury images in the future.”

When BepiColombo finally does achieve orbit around the planet, its two component satellites — ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetosphere Orbiter — will split apart and study Mercury.

The planet is not well understood compared to the likes of Venus or Mars. Prior to this, NASA’s Mariner 10 in 1975 and Messenger in 2011 were the only missions to have visited the planet, with only the latter actually achieving orbit.

Scientists at ESA and JAXA hope that BepiColombo’s various experiments will shed light on some of the mysteries of Mercury. Diverse aspects of the planet are to be studied including its core, surface, magnetic field and exosphere, to “better understand the origin and evolution of a planet close to its parent star” according to ESA.

After achieving orbit in December 2025, BepiColombo will begin its main science mission in early 2026.

Today (4 October) marks the beginning of World Space Week, which in 2021 centres around the theme of ‘women in space’.

Jack Kennedy is a freelance journalist based in Dublin