Tselina (Russian: Целина) is a Russian military space-based radio surveillance system, originally developed in the former Soviet Union. It is capable of determining the exact location of radio-emitting objects and also their type, modes of operation, and how active they are. For instance, preparation for a military operation may raise the activity of the radio communications. Detection of these communications by a space-based surveillance system can provide early warning of this activity, warning that may be unavailable by other means.
Initially divided into "overview" (Tselina-O) and "detailed" (Tselina-D), since about 1980 the system has been integrated into a single satellite, Tselina-P,[1] which is also known as Tselina-2. The system's primary subject is enemy radar equipment. Tselina has been numbered as part of the Kosmos series. In total 130 Tselina satellites have been launched.[2]