BepiColombo, a mission launched in October 2018, consisting of two space probes, one built by Japan and the other by the European Union. “They” will put themselves in perpetual orbit around Mercury in 2025, but will need six passes beforehand, including those made on the night of October 1 to 2, in order to brake a little more each time and adjust with respect to the sheer force of gravity the sun. The next “meeting” is scheduled for June 23, 2022.

Mercury may be relatively close to Earth – “only” a hundred million kilometers away – it is a planet that has not been studied much, precisely because of the difficulties posed by proximity to the Sun. In addition to their mass, there is heat: devices will sometimes have to survive temperatures up to 350 degrees Celsius.

The probe was named in honor by Giuseppe Colombo (1920-1984), an Italian mathematician to whom we owe the first calculations on this technique, often used by space engineers, consisting of using a planet’s gravitational force to speed up or slow down – or “gravity assist”.

European gear, or MPO (orbiting planet Mercury), featuring 11 instruments dedicated to studying Mercury’s surface, interior and outer layer (or Exosphere). Japanese craft, or MMO (magnetic orbital mercury), includes 5 instruments dedicated to the study of the magnetic field and the exosphere, as well as their interaction with particles scattered in the immediate environment of the planet.

The photos taken by BepiColombo during his visit are the result of a late decision: Until 2016, it was not even planned that the machine would carry three small cameras. They have low accuracy and there is more to satisfy the public’s curiosity, and was justified in 2016, than having unpublished scientific data.

Pictures black and white, Excellent quality Given the equipment, and the fact that BepiColombo was on the night side of the planet, to watch Moon-like landscape: craters – one of which appears to have been filled with lava in the distant past – and cliffs – including a 250km-long crater. Experts who analyzed data returned by the US MESSENGER probe – the only one so far orbiting Mercury, from 2011 to 2015 – estimate that the planet may have volcanic activity up to a billion years, which would be relatively recent for this planet.

Photo: ESA/BepiColombo