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Parcae / White Cloud


By © Charles P. Vick 2007 All Rights Reserved


PARCAE - White Cloud – SIGINT NOSS EORSAT Spacecraft Series – (NRO/USN/NSA Program AFP-MSD-180)

Code name PARCAE – “White Cloud” was the first in a long series of earth orbit NRO/USN/NSA, SIGINT (signals intelligence) interferometry spacecraft used by the USN. They were launched by the Atlas-E, F, H and Titan-II series of booster with a total of at least nine launches using the Atlas series and three launches using the Titan-II series. The spacecraft were actually nothing more than US Navy’s services specific sophisticated earth orbit space based earth receiving stations operating over the entire emitted electro magnetic radio spectrum frequency range. The PARCAE were flow in packages of three spacecraft not including their bus dispenser with an FW-4S apogee kick motor stage and up to four satellites on the Titan-2 launches and their bus stage. Its bus dispenser stage used a Thiokol Star-37E solid motor. The total mass of the Atlas series packages was up to 2,999 pounds while the Titan-II packages mass was up to 4,410 pounds. PARCAE first launch was apparently April 30, 1976, and its last launch was apparently May 15, 1987 on the Atlas series while its first Titan-II launch was September 5, 1988 and its last launch was April 22 1992 They were designed to monitor and pick up from the ocean through both SIGINT and interfermetric radio emissions analysis to locate ships and the direction and rate of traversing the ocean for strategic observations.

Initially the Titan-II PARCAE series had been thought to be a part of a new SBR-WASS SINGLETON Radar satellite series that was ultimately cancelled in the conceptual development phase by NRO. That program was ultimately replaced by the continuation of the PARCAE series four satellite plus bus dispenser stage program.

The technology for these SIGINT, interferometric PARCAE spacecraft series had evolved from the GRAB and DYNO series initially developed by the US Navy.

Each spin stabilized spacecraft package was about 108.73 inches long with the primary spacecraft only 40 inches long. The Atlas package has a maximum diameter of less than 72 inches. Each spacecraft had a life of three to five years while the bus package has a life of only about a month. PARCAE’s spacecraft were designed with both multiple feed horn receiving external face designs as well as surface solar arrays. The launch shroud for the Atlas series was 197.85 inches long with an external diameter of 84.2 inches while it’s inside diameter was 75-79 inches . The Titan-II launch shroud was 10 feet in diameter and 25 feet long not including the launch vehicle adapter.

The Atlas launched PARCAE spacecraft series were operated at an inclination that was at approximately 63 degrees with a perigee between 655.82 miles and an apogee of 723.78 miles with a spacecraft life of three to five years. The Titan-II series were operated at an approximate inclination of 85 degrees with a circular orbit of about 800 kilometers with at least one of the four satellites left in a separate orbit. The precise formation constellation of three spacecraft was able to receive and send the data to several global ground and ship board stations via radio signal operated by NSA/USN personnel. The data was then processed and analyzed as received for naval operations.


1. McDowell, Jonathan , U. S. Reconnaissance Satellites Programs, Part 2: Beyond Imaging, Quest, Vol. 4, No. 4.

2. Dr Day, Dwayne A., Robotic Ravens, Spaceflight, Vol. 47, No. 11, Nov. 2005, pp. 426-433.

The U.S. Navy's "White Cloud" Spaceborne ELINT System, Andronov and Obozreniye (trans. Allen Thomson), Foreign Military Review, No.7, 1993.

Parcae Atlas Payloads

Parcae Titan-II Payloads

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Page last modified: 21-07-2011 13:05:08 ZULU