Naval Ocean Surveillance System


The Naval Ocean Surveillance System is a series of signals intelligence satellites that have conducted electronic signals intelligence for the U.S. Navy since the early 1970s. The first series of satellites were codenamed "White Cloud" or "PARCAE", while second and third-generation satellites have used the codenames "Ranger" and "Intruder".
The system is operated by the U.S. Navy and its main purpose was tactical geolocation of Soviet Navy assets during the Cold War. The NOSS satellites operate in clusters in low Earth orbit to detect radar and other electronic transmissions from ships at sea and locate them using the Time Difference Of Arrival technique.

Satellites

First generation

Second generation

Third generation

Cost

The costs of the NOSS satellites, which were destroyed in a Titan IV launch failure in 1993, were US$800 million.