Venus Express

Venus Express was ESA's first Venus orbiter, launched in November 2005 and operating around the planet from April 2006 until the mission ended in December 2014. Its elliptical, near-polar orbit supported repeated investigations of atmospheric chemistry, clouds, circulation, surface thermal emission and the interaction of the upper atmosphere with the solar wind. Infrared observations resolved the changing structure of the southern polar vortex, while ultraviolet and infrared spectroscopy identified a tenuous ozone layer and traced atmospheric escape. Cloud tracking measured variations in the rapidly circulating atmosphere. Changes in sulfur dioxide and surface thermal properties provided evidence relevant to recent volcanism, with individual interpretations requiring further investigation. Near the end of the mission, a low-altitude aerobraking campaign also sampled the upper atmosphere; later orbit-raising attempts ended as propellant was exhausted.