Image of the Venusian atmosphere at 60km over the south pole (yellow dot) using Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Venus Express (Image: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/University of Oxford)
An unexpected measurement has been achieved with the Venus Express, a satellite currently studying the atmosphere of Venus. While the satellite was not fitted with instruments to directly measure atmosphere density, the scientists have discovered by measuring the drag as the Venus Express experiences air resistance that the atmosphere is 60 percent thinner than expected. This "working on the fly" approach could allow the scientists to extend the life of the craft allowing them to collect more data.