Tselina was a series of Russian ELINT (electronic intelligence) satellites, the first of which was launched on June 26, 1967; Tselina means "untouched soil." There were two basic types. Tselina I was used mostly for tracking NATO shipping. Similar to the American SB-WASS system, it operated in a constellation that detected ELINT data and then compared readings from different locations over time to pinpoint the position of the source. It then transmitted weapons targeting data, relayed by communications satellites either to ground stations or directly to Russian ships. Tselina II was a more general-purpose system, similar to Mercury-ELINT.