Krasno-Oskol Reservoir, satellite radar image. North is at top. At centre the Krasno-Oskol Reservoir (created in 1958) is located in the Ukraine, behind a dam on the Oskol River. Fields and forests surround the reservoir, with the different crops in the fields reflecting the radar differently. This image, obtained on 24 June 2010 and showing an area around 30 kilometres across, was among the first obtained by the TanDEM-X satellite. TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is a European satellite that uses X-band (microwave) synthetic aperture radar (SAR) to observe the Earth from space.