Moscow region, satellite radar image. North is at top. This area is some 30 kilometres north of Moscow, Russia. At centre left is Sheremetyevo International Airport (rectangle). This airport opened in 1959 and is one of the largest in Russia. At centre right is the Pirogovskoye Reservoir. This image, obtained on 24 June 2010 and showing an area around 25 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.