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JUICY tests. The Jupiter Icy Moons Explorer is a European Space Agency (ESA) mission scheduled to launch in 2022. Here, engineers at ESA in Noordwijk, the Netherlands, test a 1:18-scaled version of the spacecraft’s 16-metre-long radar antenna in a radio-interference-proof chamber. The instrument will probe down to nine kilometres under the surfaces of the Jovian moons Ganymede, Europa and Callisto to study the water oceans thought to be hidden beneath their ice crusts.