The BepiColombo mission to Mercury was launched by an Ariane 5 rocket from Europe’s Spaceport in Kourou (French Guiana) last month.

The mission is a joint endeavour between the European Space Agency (ESA) (www.esa.int) and the Japan Aerospace Exploration Agency (JAXA) (www.global.jaxa.jp).

It is the first European mission to Mercury (the smallest and least explored planet in the inner solar system) and the first to send two spacecraft to make “complementary measurements of the planet and its dynamic environment at the same time”.

Jan Wörner, ESA director general, said: “Launching BepiColombo is a huge milestone for ESA and JAXA, and there will be many great successes to come. Beyond completing the challenging journey, this mission will return a huge bounty of science.

"It is thanks to the international collaboration and the decades of efforts and expertise of everyone involved in the design and building of this incredible machine that we are now on our way to investigating Mercury’s mysteries.”

BepiColombo comprises two science orbiters: ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter.

The ESA-built Mercury Transfer Module will carry them to Mercury using a combination of solar electric propulsion and gravity-assist fly-bys — with one fly-by of Earth, two of Venus and six of Mercury — before going into orbit around Mercury in late 2025.

ESA flight director Andrea Accomazzo said: “BepiColombo is one of the most complex interplanetary missions we have ever flown.

"One of the biggest challenges is the Sun’s enormous gravity, which makes it difficult to place a spacecraft into a stable orbit around Mercury.

"We have to constantly brake to ensure a controlled fall towards the Sun, with the ion thrusters providing the low thrust needed over long durations of the cruise phase.

"Other challenges include the extreme temperatures that the spacecraft will endure; these will range from -180ºC to over 450ºC.”