The Naval Ocean Surveillance System (NOSS) 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". According to the Union of Concerned Scientists in 2023, the system may be called the Space-Based Wide Area Surveillance System (SB-WASS). The system is operated by the United States Navy, and its main purpose was tactical geolocation of Soviet Navy assets during the Cold War. NOSS involves satellite clusters operating 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

{|class="wikitable sortable" ! Name ! ID ! Launch date ! Launch vehicle ! Launch site ! NROL designation ! Perigee ! Apogee ! Inclination ! Remarks

First generation

Second generation

Third generation

Cost

The costs of the NOSS satellites (excluding costs for the launch vehicle), which were destroyed in a Titan IV launch failure in 1993, were US$800 million (inflation adjusted US$ 0 billion in ).