The Don-2N radar is a large missile defense and early warning active electronically scanned array radar outside Moscow, and a key part of the Russian A-135 anti-ballistic missile system designed for the defense of the capital against ballistic missiles. Located near Sofrino in Pushkinsky District of Moscow Oblast, it is a quadrangular frustum 33 m (108 ft) tall with sides 130 m (427 ft) long at the bottom, and 90 m (295 ft) long at the top. Each of its four faces has an 18 m (59 ft) diameter Super high frequency band radar giving 360 degree coverage. To the right of each circular search and track array, separated by a vertical structure for shielding, is a square antenna array for guiding the interceptor missile by data link. The system is run by an Elbrus-2 supercomputer.