Preparing the Juice mission to Jupiter has involved testing for all kinds of contingencies, down to the smallest of scales. This microscopic view shows surface damage to a tiny silver interconnector after being exposed to erosive atomic oxygen known to be found surrounding Jupiter's moon Ganymede.

Due to launch on April 13 to begin an eight-year journey to the largest planet in the solar system, ESA's Jupiter Icy Moons Explorer, Juice, will spend three and a half years in the Jupiter system, and in the final phase of its exploration will go into orbit around the largest Jovian moon, Ganymede.

However, previous observations by the Hubble Space Telescope have revealed auroral glows around Ganymede due to the presence of 'atomic oxygen'—individual atoms of oxygen at the fringes of the moon's scanty atmosphere, the result of standard oxygen molecules being broken apart by the powerful radiation belts surrounding Jupiter.

ESA materials engineer Adrian Tighe explains, "Atomic oxygen is also experienced in Earth orbit, due to oxygen molecules being dissociated by ultraviolet radiation from the Sun, and all Earth-orbiting missions below about 1000 km altitude are designed to resist it.