Venus has no seasons, slow rotation and a very massive atmosphere, which is mainly carbon dioxide with clouds primarily of sulphuric acid droplets. Infrared observations by previous missions to Venus revealed a bright 'dipole' feature surrounded by a cold 'collar' at its north pole. The polar dipole is a 'double-eye' feature at the centre of a vast vortex that rotates around the pole, and is possibly associated with rapid downwelling. The polar cold collar is a wide, shallow river of cold air that circulates around the polar vortex. One outstanding question has been whether the global circulation was symmetric, such that a dipole feature existed at the south pole. Here we report observations of Venus' south-polar region, where we have seen clouds with morphology much like those around the north pole, but rotating somewhat faster than the northern dipole. The vortex may extend down to the lower cloud layers that lie at about 50 km height and perhaps deeper. The spectroscopic properties of the clouds around the south pole are compatible with a sulphuric acid composition.

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Data acquisition in planetary remote sensing missions is influenced by complex environmental, resource and instrument-specific constraints. This impedes to perform observations at any given time during the mission and with any of the instruments composing the scientific payload. This paper presents an approach to the automatic scheduling of the acquisition operations of a remote sensing instrument composing the scientific payload of a mission. The methodology first subdivides the long available observation time intervals into shorter segments and then performs a selection of them, producing an acquisition schedule, optimized with respect to the scientific requirements, the instrument characteristics and the mission constraints. The scheduling problem is modeled as a multi-objective optimization problem and solved by using Genetic Algorithms (GAs). GAs are able to efficiently explore the solution space by considering different competing objective functions, reaching high quality solutions. These solutions represent different optimized tradeoffs among the considered instrument-specific quality metrics. The approach is demonstrated on the operations of RIME (Radar for Icy Moons Exploration), a radar sounder onboard JUpiter ICy moons Explorer (JUICE). The obtained results show the high potential of the proposed methodology.