First glimpse of Mercury for BepiColombo

BepiColombo is projected to approach Mercury at a distance of around 200km in this first flyby manoeuvre. Credit: ESA/ATG medialab

The ESA-JAXA BepiColombo mission to Mercury, carrying instrumentation created with Leicester expertise, will make the first of six flybys of its destination planet this week before entering orbit in 2025.

Following the mission’s last Venus flyby in August, the spacecraft’s next exciting encounter is with Mercury at 00:34 BST this Saturday, 2 October. It will swoop by the planet at an altitude of about 200 km, capturing imagery and science data that will give scientists a tantalizing first taste of what’s to come in the main mission.

BepiColombo carries the Mercury Imaging X-ray Spectrometer (MIXS), developed by a Europe-wide consortium led by the University of Leicester, including institutes and companies in the UK, Finland, Spain, Germany and France.

MIXS will study the elemental composition of the surface of Mercury and its data will revolutionise our understanding of Mercury’s surface after it goes into orbit in 2025.

Professor Emma Bunce is Head of the School of Physics and Astronomy at the University of Leicester and Principal Investigator (PI) for the MIXS instrument.

She said: “We are very excited for the first Mercury flyby and this is a key moment in the mission. While our instrument is not able to fully operate in science mode (because it is staring at the side of the Mercury Transfer Module!), we are able to take the opportunity to run some health checks on the instrument.

“However, seeing our final destination up close for the first time since launch is a really special moment for the team. We are now regularly in the vicinity of Mercury’s orbit for the remainder of the cruise and Bepi will fly close to Mercury a further five times, slowing down each time, until the spacecraft is finally captured into orbit around Mercury in 2025.

“It’s a long wait until we begin the main mission, but it is certainly an exciting ride!”

Credit: ESA

The mission comprises two science orbiters which will be delivered into complementary orbits around the planet by the Mercury Transfer Module in 2025.

The European Space Agency (ESA)-led Mercury Planetary Orbiter and the Japanese Aerospace Exploration Agency (JAXA)-led Mercury Magnetospheric Orbiter, Mio, will study all aspects of this mysterious inner planet 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.

BepiColombo will make 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.

Dr Beatriz Sánchez-Cano, of the School of Physics and Astronomy, is one of only six guest investigators – and the only one based in the UK – for the mission, and used observations from both Venus flybys to better understand the planet’s complex atmosphere, ionosphere and interaction with the Sun’s solar wind.

Gravitational flybys require extremely precise deep-space navigation work, ensuring that the spacecraft is on the correct approach trajectory.

As BepiColombo is more than 100 million kilometres away from Earth, with light taking 350 seconds (about six minutes) to reach it, being on target to within just two kilometres is no easy feat.

“It is because of our remarkable ground stations that we know where our spacecraft is with such precision. With this information, the Flight Dynamics team at ESOC know just how much we need to manoeuvre, to be in the right place for Mercury’s gravitational assist,” explained Elsa Montagnon, Spacecraft Operations Manager for the mission.

“As is often the case, our mission’s path has been planned so meticulously that no further correction manoeuvres are expected for this upcoming flyby. BepiColombo is on track.”

For the closest images captured in the fleeting glimpse of our Solar System’s innermost planet, it should be possible to identify large impact craters on the surface. Mercury has a heavily cratered surface much like Earth’s Moon, and holds a record of the planet’s 4.6 billion year history. Mapping the surface of Mercury and analysing its composition will help scientists understand more about its formation and evolution.

Find out more about Leicester’s involvement in the BepiColombo mission at