WHITE CLOUD satellite

WHITE CLOUD satellites, also called PARCAE, CLASSIC WIZARD or the Naval Ocean Surveillance System (NOSS) are electronic intelligence satellites, launched in clusters of one main and three "daughters", starting in the 1970s. Their principal mission was locating Soviet ships based on the ships' radar and radio transmissions.

The PARCAE code name is a rather descriptive mythological analogy:

The mythological Parcae were the three daughters of Zeus and the goddess Themida (the SSU satellites are launched in groups of three and fly relatively close together.) One of the daughters spins the thread of fate for each mortal (one satellite has a wide observation swath, but cannot exactly determine the coordinates of radio emitters). The second daughter measures out a length of thread for each person (when two satellites get a fix on the shipborne emitters, the position is obtained, but with some ambiguity). The third sister (Atropos - "she from whom one may not flee") cuts the measured thread of life (the third satellite, getting a fix on the emitters' signals, enables their coordinates to be determined precisely and then transmitted to Navy ships for weapons employment.

Positions are calculated by the different times of arrival of the electromagnetic signals at the different satellites, between 30 and 240 km apart, of individual clusters. Multiple clusters can be orbiting at a given time, and, if that is the case, more accurate fixes can be determined by combining the measurements from different clusters.

The long-term replacement for this system was the Space Based Wide Area Surveillance System (SB-WASS). This system would meet both Navy requirements for defending at-sea groups long range Soviet aviation, while the Air Force requirements wanted to extend strategic air defense warning network over the Arctic Ocean. There appear to have been both acknowledged and unacknowledged versions of SB-WASS, with the Navy wanting it to be passive infrared while the Air Force wanting rotating radar antenna sensors. While there was indication that NATO and Canada possibly wanted to participate, at least the overt part was terminated in 1991 after some engineering test flights of both Air Force and Navy versions.