The European Venus Express probe began orbiting Venus in 2006.
Atmospheric isotope data and other information gathered by the spacecraft have been interpreted as evidence that the planet once had surface water.
The probe has made a detailed study of the planet's features, including surface temperatures and wind patterns. Venus Express was also positioned to look back at the Earth as part of a project to find ways of detecting Earth-like planets outside the Solar System.
Photo: Artist's impression of Venus Express (ESA)
A European probe finds evidence of past water on Venus.
Patrick Moore and his guests give a rundown of Earth's 'evil twin'.
Sir Patrick Moore and his guests Professor Fred Taylor from Oxford University and Dr Dave Rothery from The Open University discuss what we know about Venus from the probes that have visited the planet.
Scientists cheer as the European probe starts its mission.
As Europe's first probe to Venus entered orbit in April 2006, the BBC's Christine McGourty reported on the spacecraft's mission to study the planet's runaway greenhouse effect. The thick Venusian carbon dioxide atmosphere is responsible for searing temperatures at the surface.
Venus Express (VEX) is the first Venus exploration mission of the European Space Agency. Launched in November 2005, it arrived at Venus in April 2006 and has been continuously sending back science data from its polar orbit around Venus. Equipped with seven scientific instruments, the main objective of the mission is the long term observation of the Venusian atmosphere. The observation over such long periods of time has never been done in previous missions to Venus, and is key to a better understanding of the atmospheric dynamics. It is hoped that such studies can contribute to an understanding of atmospheric dynamics in general, while also contributing to an understanding of climate change on Earth. The mission is currently funded by ESA until 31 December 2014.