Naval Ocean Surveillance System


The NOSS 3-4 duo (2007-027A & C) crossing through the Pleiades. Movement in this 10 second exposure is from top to bottom, the A object is leading.
A NOSS satellite Trio passes the Moon.

The Naval Ocean Surveillance System (NOSS) is a series of signals intelligence satellites that have conducted electronic signals intelligence for the U.S. Navy[citation needed] 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 U.S. Navy and its main purpose was tactical geolocation of Soviet Navy assets during the Cold War. The NOSS satellites operate in clusters 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.[1]


Name ID Launch date Launch vehicle Launch site NROL designation Perigee Apogee Inclination Remarks

First generation

OPS 6431 SSU-1 1976-038C 1976-04-30 Atlas E/F-MSD VAFB SLC-3W N/A 1,092 km 1,128 km 63.5° Dispenser designated OPS 6431 and catalogued as 1976-038A
OPS 6431 SSU-2 1976-038D
OPS 6431 SSU-3 1976-038J
OPS 8781 SSU-1 1977-112D 1977-12-08 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-2 1977-112E
OPS 8781 SSU-3 1977-112F
OPS 7245 SSU-1 1980-019C 1980-03-03 Atlas E/F-MSD VAFB SLC-3W 1,035 km 1,150 km 63.0° Dispenser designated OPS 7245 and catalogued as 1980-019A
OPS 7245 SSU-2 1980-019D
OPS 7245 SSU-3 1980-019G
OPS 3255 SSU-1 N/A 1980-12-09 Atlas E/F-MSD VAFB SLC-3W Failed to orbit Dispenser designated OPS 3255, loss of control after engine failure, followed by explosion
OPS 3255 SSU-2 N/A
OPS 3255 SSU-3 N/A
OPS 0252 SSU-1 1983-008E 1983-02-09 Atlas H-MSD VAFB SLC-3E 1,063 km 1,186 km 63.40° Dispenser designated OPS 0252 and catalogued as 1983-008A
OPS 0252 SSU-2 1983-008F
OPS 0252 SSU-3 1983-008H
OPS 6432 SSU-1 1983-056C 1983-06-09 Atlas H-MSD VAFB SLC-3E 851 km 1,363 km 63.4° Dispenser designated OPS 6432 and catalogued as 1983-056A
OPS 6432 SSU-2 1983-056D
OPS 6432 SSU-3 1983-056G
OPS 8737 SSU-1 1984-012C 1984-02-05 Atlas H-MSD VAFB SLC-3E 1,052 km 1,172 km 63.4° Dispenser designated OPS 8737 and catalogued as 1984-012A
OPS 8737 SSU-2 1984-012D
OPS 8737 SSU-3 1984-012F
USA-16 1986-014C 1986-02-09 Atlas H-MSD VAFB SLC-3E 1,049 km 1,166 km 63.0° Dispenser designated USA-15 and catalogued as 1986-014A
USA-17 1986-014F
USA-18 1986-014H
USA-23 1987-043E 1987-05-15 Atlas H-MSD VAFB SLC-3E 1,045 km 1,179 km 62.9° Dispenser designated USA-22 and catalogued as 1987-043A
USA-24 1987-043F
USA-26 1987-043H

Second generation

USA-60 1990-050E 1990-06-08 Titan IV(405)A CCAFS LC-41 N/A 1,071 km 1,146 km 63.4° Dispenser designated USA-59 and catalogued as 1990-050A
USA-61 1990-050F
USA-62 1990-050H
USA-74 1991-076C 1991-11-08 Titan IV(403)A VAFB SLC-4E 1,052 km 1,164 km 63.4° Dispenser designated USA-72 and catalogued as 1991-076A
USA-76 1991-076D
USA-77 1991-076E
Unnamed N/A 1993-08-02 Titan IV(403)A VAFB SLC-4E Failed to orbit Exploded due to crack in solid rocket motor caused by poor repair
Unnamed N/A
Unnamed N/A
USA-119 1996-029A 1996-05-12 Titan IV(403)A VAFB SLC-4E 1,050 km 1,166 km 63.4° Dispenser designated USA-122 and catalogued as 1996-029D
USA-120 1996-029B
USA-121 1996-029C

Third generation

USA-160 2001-040A 2001-09-08 Atlas IIAS VAFB SLC-3E NROL-13 1,100 km 1,100 km 63°
Unnamed* 2001-040C
USA-173 2003-054A 2003-12-02 Atlas IIAS VAFB SLC-3E NROL-18 1,013 km 1,200 km 63.4°
Unnamed* 2003-054C
USA-181 2005-004A 2005-02-03 Atlas IIIB CCAFS SLC-36B NROL-23 1,011 km 1,209 km 63.4°
Unnamed* 2005-004C
USA-194 2007-027A 2007-06-15 Atlas V 401 CCAFS SLC-41 NROL-30 1,053 km 1,163 km 63.4° Launched into lower orbit than planned, spacecraft corrected under own power, at expense of operational life
Unnamed* 2007-027C
USA-229 2011-014A 2011-04-15 Atlas V 411 VAFB SLC-3E NROL-34 1,014 km 1,207 km 63.4°
Unnamed* 2011-014B
USA-238 2012-048A 2012-09-13 Atlas V 401 VAFB SLC-3E NROL-36 1,056 km 1,158 km 63.4°
Unnamed* 2012-048P
USA-264 2015-058A 2015-10-08 Atlas V 401 VAFB SLC-3E NROL-55 1,013 km 1,201 km 63.4°
Unnamed* 2015-058R
USA-274 2017-011A 2017-03-01 Atlas V 401 VAFB SLC-3E NROL-79 1,010 km 1,204 km 63.4°
Unnamed* 2017-011B
* - One satellite from each third generation pair is officially catalogued as debris
data from [1], [2]
NOSS 3-3 duo passing by Polaris (bright star at the bottom). Movement in this 12.3s exposure is from upper-left to bottom-right; the A object is leading. 06-Feb-2016, 18:52(UT+2), Kyiv


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$800 million (inflation adjusted US$ 1.4 billion in 2020).[2]

See also


  1. ^ "NOSS Double and Triple Satellite Formations".
  2. ^ Weiner, Tim (1993-08-04). "Titan Lost Payload: Spy-Satellite System Worth $800 Million". New York Times.

External links

  • Augment-reality satellite viewing
  • NOSS @
  • BBC - h2g2 - Naval Ocean Surveillance Satellites - a 'UFO'