Naval Ocean Surveillance System


[Image:NOSS-Trio.jpg|thumb|290px|A NOSS satellite trio passes the Moon.]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 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

First generation NOSS-1 (1976–1987)

The first generation of NOSS satellites was developed by the Naval Research Laboratory (NRL) based on the previous generations of electronic listening satellites: Grab and Poppy. Eight clusters of 3 satellites were launched between 1976 and 1987.
Each launch carried out by an Atlas F, E or H) with a dispenser placed three sub-satellites into orbit. The dispenser is responsible, thanks to its solid propellant engine, for placing the three sub-satellites into their operational orbit of 1,050 × 1,150 km with an inclination of 63°. To be able to track ships, the three satellites maintain a triangular formation with a distance between 30 and 240 km.
Each satellite has on one of its faces a series of antennas intended to collect the signals emitted by ships which are kept constantly turned towards the Earth. The satellite's orientation is maintained by gravity gradient pointed towards the Earth thanks to a boom 10 to 15 meters long.

Second generation NOSS-2 (1990–1996)

The second generation of NOSS satellites, first launched in 1990, adopted the same configuration as the previous generation. The satellites were launched in clusters of three with a Titan Launch Dispenser responsible for positioning them in their operational orbit and adopted a triangular configuration.
Four NOSS-2 cluster launches took place between 1990 and 1996. The satellites were much heavier and had to be launched by a Titan IV rocket.
The dispenser played a secondary role: after ejecting the NOSS satellites, it placed itself in an elliptical orbit where a dedicated telecommunications module was used for tactical military telecommunications.

Third generation NOSS-3 (2001–2017)

Image:NOSS 3-3 20160206-1852 Kyiv.jpg|thumb|290px|NOSS 3-3 duo passing by Polaris. Movement in this 12.3-seconds exposure is from upper-left to bottom-right; the A object is leading. 6 February 2016, 18:52, Kyiv.
Image:NOSS3 4 Plei 29012011 6.jpg|290px|thumb|The NOSS 3-4 duo crossing through the Pleiades. Movement in this 10-second exposure is from top to bottom, the A object is leading.
The third generation was deployed after 2001. Unlike previous generations, the satellites are launched and operate in pairs and don't require a dispenser. The combined mass of a satellites pair is 6,500  kg. The orbit is identical to previous generations: 1,100 × 1,100 km with an inclination of 64°.
Eight pairs of satellites were launched between 2001 and 2017. The launchers used were Atlas II, Atlas III and Atlas V.
NameIDLaunch dateLaunch vehicleLaunch siteNROL designationPerigeeApogeeInclinationRemarks
USA-1602001-040A8 September 2001Atlas IIASVAFB, SLC-3ENROL-131,100 km1,100 km63.0°
Unnamed*2001-040C8 September 2001Atlas IIASVAFB, SLC-3ENROL-131,100 km1,100 km63.0°
USA-1732003-054A2 December 2003Atlas IIASVAFB, SLC-3ENROL-181,013 km1,200 km63.4°
Unnamed*2003-054C2 December 2003Atlas IIASVAFB, SLC-3ENROL-181,013 km1,200 km63.4°
USA-1812005-004A3 February 2005Atlas IIIBNROL-231,011 km1,209 km63.4°
Unnamed*2005-004C3 February 2005Atlas IIIBNROL-231,011 km1,209 km63.4°
USA-1942007-027A15 June 2007Atlas V 401CCAFS, SLC-41NROL-301,053 km1,163 km63.4°Launched into lower orbit than planned, spacecraft corrected under own power, at expense of operational life.
Unnamed*2007-027C15 June 2007Atlas V 401CCAFS, SLC-41NROL-301,053 km1,163 km63.4°Launched into lower orbit than planned, spacecraft corrected under own power, at expense of operational life.
USA-2292011-014A15 April 2011Atlas V 411VAFB, SLC-3ENROL-341,015 km1,207 km63.46°
Unnamed*2011-014B15 April 2011Atlas V 411VAFB, SLC-3ENROL-341,015 km1,207 km63.46°
USA-2382012-048A13 September 2012Atlas V 401VAFB, SLC-3ENROL-361,056 km1,158 km63.4°
Unnamed*2012-048P13 September 2012Atlas V 401VAFB, SLC-3ENROL-361,056 km1,158 km63.4°
USA-2642015-058A8 October 2015Atlas V 401VAFB, SLC-3ENROL-551,013 km1,201 km63.4°
Unnamed*2015-058R8 October 2015Atlas V 401VAFB, SLC-3ENROL-551,013 km1,201 km63.4°
USA-2742017-011A1 March 2017Atlas V 401VAFB, SLC-3ENROL-791,010 km1,204 km63.4°
Unnamed*2017-011B1 March 2017Atlas V 401VAFB, SLC-3ENROL-791,010 km1,204 km63.4°

Cost

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