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".
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 (1960–1962) and Poppy (1962–1971). 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. +First generation (Parcae) Name ID Launch date Launch vehicle Launch site Perigee Apogee Inclination Remarks1976-038C 30 April 1976 Atlas E/F-MSD VAFB, SLC-3W 1,092 km 1,128 km 63.5° Dispenser designated OPS 6431 and catalogued as 1976-038A.OPS 6431 SSU-21976-038DOPS 6431 SSU-31976-038JOPS 8781 SSU-11977-112D 8 December 1977 Atlas E/F-MSD VAFB, SLC-3W 1,054 km 1,169 km 63.4° Dispenser designated OPS 8781 and catalogued as 1977-112A.OPS 8781 SSU-21977-112EOPS 8781 SSU-31977-112FOPS 7245 SSU-11980-019C3 March 1980Atlas E/F-MSDVAFB, SLC-3W1,035 km 1,150 km 63.0°Dispenser designated OPS 7245 and catalogued as 1980-019A.OPS 7245 SSU-21980-019DOPS 7245 SSU-31980-019GOPS 3255 SSU-1N/A9 December 1980Atlas E/F-MSDVAFB, SLC-3WFailed to orbit Dispenser designated OPS 3255, loss of control after engine failure, followed by explosion.OPS 3255 SSU-2N/AOPS 3255 SSU-3N/AOPS 0252 SSU-11983-008E9 February 1983Atlas H-MSDVAFB, SLC-3E1,063 km 1,186 km 63.40°Dispenser designated OPS 0252 and catalogued as 1983-008A.OPS 0252 SSU-21983-008FOPS 0252 SSU-31983-008HOPS 6432 SSU-11983-056C9 June 1983Atlas H-MSDVAFB, SLC-3E851 km 1,363 km 63.4°Dispenser designated OPS 6432 and catalogued as 1983-056A.OPS 6432 SSU-21983-056DOPS 6432 SSU-31983-056GOPS 8737 SSU-11984-012C5 February 1984Atlas H-MSDVAFB, SLC-3E1,052 km 1,172 km 63.4°Dispenser designated OPS 8737 and catalogued as 1984-012A.OPS 8737 SSU-21984-012DOPS 8737 SSU-31984-012FUSA-161986-014E 9 February 1986Atlas H-MSDVAFB, SLC-3E1,049 km 1,166 km 63.0°Dispenser designated USA-15 and catalogued as 1986-014A.USA-171986-014FUSA-181986-014HUSA-231987-043E15 May 1987 Atlas H-MSDVAFB, SLC-3E1,045 km 1,179 km 62.9°Dispenser designated USA-22 and catalogued as 1987-043A.USA-241987-043FUSA-261987-043H
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 (TLD) responsible for positioning them in their operational orbit (1,100 × 1,100 km with an inclination of 63.4°) and adopted a triangular configuration.
Four NOSS-2 cluster launches took place between 1990 and 1996 (one failure in 1993). 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 (1,100 × 9,000 km) where a dedicated telecommunications module (Satellite Launch Dispenser Communications System or SLDCOM) was used for tactical military telecommunications. +Second generation Name ID Launch date Launch vehicle Launch site Perigee Apogee Inclination RemarksUSA-601990-050E8 June 1990 CCAFS, LC-411,071 km 1,146 km 63.4°Dispenser designated USA-59 and catalogued as 1990-050A.USA-611990-050FUSA-621990-050HUSA-741991-076C8 November 1991Titan IV(403)AVAFB, SLC-4E1,052 km 1,164 km 63.4°Dispenser designated USA-72 and catalogued as 1991-076A.USA-761991-076DUSA-771991-076EUnnamedN/A2 August 1993Titan IV(403)AVAFB, SLC-4EFailed to orbit Exploded due to crack in solid rocket motor caused by poor repair.UnnamedN/AUnnamedN/AUSA-1191996-029A12 May 1996Titan IV(403)AVAFB, SLC-4E1,050 km 1,166 km 63.4°Dispenser designated USA-122 and catalogued as 1996-029D.USA-1201996-029BUSA-1211996-029C
Third generation NOSS-3 (2001–2017)
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. +Third generation (Intruder) Name ID Launch date Launch vehicle Launch site NROL designation Perigee Apogee Inclination RemarksUSA-1602001-040A8 September 2001Atlas IIASVAFB, SLC-3ENROL-131,100 km 1,100 km 63.0°Unnamed*2001-040CUSA-1732003-054A2 December 2003Atlas IIASVAFB, SLC-3ENROL-181,013 km 1,200 km 63.4°Unnamed*2003-054CUSA-1812005-004A3 February 2005Atlas IIIBNROL-231,011 km 1,209 km 63.4°Unnamed*2005-004CUSA-1942007-027A15 June 2007Atlas V 401CCAFS, SLC-41NROL-301,053 km 1,163 km 63.4°Launched into lower orbit than planned, spacecraft corrected under own power, at expense of operational life.Unnamed*2007-027CUSA-2292011-014A15 April 2011Atlas V 411VAFB, SLC-3ENROL-341,015 km 1,207 km 63.46°Unnamed*2011-014BUSA-2382012-048A13 September 2012Atlas V 401VAFB, SLC-3ENROL-361,056 km 1,158 km 63.4°Unnamed*2012-048PUSA-2642015-058A8 October 2015Atlas V 401VAFB, SLC-3ENROL-551,013 km 1,201 km 63.4°Unnamed*2015-058RUSA-2742017-011A1 March 2017Atlas V 401VAFB, SLC-3ENROL-791,010 km 1,204 km 63.4°Unnamed*2017-011B
Note: * One satellite from each third generation pair is officially catalogued as debris.
Fourth generation NOSS-4 (2022–) The fourth generation of NOSS satellites seems to consist of single-satellite launches, as no secondary payload has been detected in any of the launches of the fourth generation to date. This would suggest an improved iteration of those satellites capable of relying on a single unit to perform their maritime tracking tasks via radio transmission detection. +Fourth generation (Intruder F/O) Name ID Launch date Launch vehicle Launch site NROL designation Perigee Apogee Inclination RemarksUSA-3272022-040A17 April 2022Falcon 9 Block 5VAFB, SLC-4ENROL-851,100 km1,100 km63.4°Launched.USA-4982025-060A24 March 2025Falcon 9 Block 5CCAFS, SLC-40NROL-691,100 km1,100 km63.4°Launched.USA-57010 December 2025Falcon 9 Block 5CCAFS, SLC-40NROL-771,100 km1,100 kmLaunched.USA-61930 July 2026Falcon 9 Block 5CCAFS, SLC-40NROL-951,100 km1,100 kmLaunched.
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$800 million (inflation adjusted US$ billion in ).
See also Poppy (satellite) Yaogan CERES (satellite)
References
External links NOSS @ astronautix.com BBC – h2g2 – Naval Ocean Surveillance Satellites – a 'UFO'