The Cheops satellite being fuelled with hydrazine at Europe's Spaceport in Kourou, French Guiana, on 23 November. A highly specialised team of fuellers is at work, protected by special suites. Fuelling is controlled via a dedicated set-up which allows to control accurately the quantity of propellant loaded in the satellite tank.

Scheduled for launch on a Soyuz-Fregat rocket on 17 December, Cheops is ESA’s first mission dedicated to the study of extrasolar planets, or exoplanets. It will observe bright stars that are already known to host planets, measuring minuscule brightness changes due to the planet’s transit across the star’s disc.

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