Context: Following a series of tests conducted in space over the past five months, the ESA-JAXA BepiColombo mission has successfully completed its near-Earth commissioning phase and is now ready for the operations that will take place during the cruise and, eventually, for its scientific investigations at Mercury.

About BepiColombo:

BepiColombo is a joint mission between ESA and the Japan Aerospace Exploration Agency (JAXA), executed under ESA leadership.

The mission comprises two spacecraft: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The MPO will study the surface and internal composition of the planet, and the MMO will study Mercury’s magnetosphere, that is, the region of space around the planet that is influenced by its magnetic field.

Need: The scientific interest in going to Mercury lies in the valuable information that such a mission can provide to enhance our understanding of the planet itself as well as the formation of our Solar System; information which cannot be obtained with observations made from Earth.

Challenges: Europe’s space scientists have identified the mission as one of the most challenging long-term planetary projects, because Mercury’s proximity to the Sun makes it difficult for a spacecraft to reach the planet and to survive in the harsh environment found there.

Significance: Mercury is a poorly explored planet. So far, only two spacecraft have visited the planet: NASA’s Mariner 10, which flew past three times in 1974–5 and returned the first close-up images of the planet, and NASA’s MESSENGER spacecraft, which performed three flybys (two in 2008 and one in 2009) before entering orbit around the planet in March 2011. The information obtained when BepiColombo arrives will throw light not only on the composition and history of Mercury, but also on the history and formation of the inner planets in general, including Earth.