The Satellite Data System (SDS) is a system of United States military communications satellites. At least three generations have been used: SDS-1 from 1976 to 1987; SDS-2 from 1989 to 1996; SDS-3 from 1998 to the present. It is believed that these satellites were known by the code name Quasar. [1] The first generation was named simply 'SDS', the second generation was named 'Quasar' and the third generation each had their own designations. [2]
SDS satellites have a highly elliptical orbit, going from about 300 kilometers at perigee to roughly 39,000 km at apogee in order to allow communications with polar stations that cannot contact geosynchronous satellites. The high apogee meant that the polar regions were visible for long amounts of time, and only two satellites were required in order to achieve constant communications ability. In addition, two geostationary satellites appear to be part of the system. The SDS satellites were constructed by Hughes Aircraft Company.
The primary purpose of the SDS satellites is to relay imagery from low-flying reconnaissance satellites, notably the Keyhole optical reconnaissance and Lacrosse/Onyx radar reconnaissance satellites to ground stations in the United States. [3]
Each SDS-1 satellite had 12 channels available for Ultra high frequency (UHF) communication. They were cylindrical in shape, roughly 25 ft (7.6 m) long. 980 watts of electrical power were available from solar panels and batteries. The SDS-1 had a mass of 630 kg (1,390 lb) and was launched on Titan-3B rockets. The SDS-1 satellites had similar orbits to the Air Force's Jumpseat ELINT satellites. [4]
It has been speculated that the early satellites served as data relays for the first KH-11 Kennen reconnaissance satellites. [5]
The SDS-2 is significantly more massive at 2,335 kg (5,148 lb), with three separate communication dishes, including one for a K-band downlink. Two dishes are 4.5 m (15 ft) in diameter, while the third is 2 m (6 ft 7 in) in diameter. The solar arrays generate 1238 watts of power. It is believed that the Space Shuttle has been used to launch several satellites, possibly on missions STS-28, STS-38, and STS-53. Other launches have used the Titan IV launch vehicle.
| Name | COSPAR ID [6] SATCAT № | Launch date | Launch vehicle | Launch site | Launch designation | Perigee | Apogee | Inclination | Remarks |
|---|---|---|---|---|---|---|---|---|---|
First generation | |||||||||
| OPS 7837 | 1976-050A 08871 | 2 June 1976 | Titan III(34)B | VAFB, SLC-4W | SDS F-1 | 380 km | 39315 km | 63.3 deg | |
| OPS 7940 | 1976-080A 09270 | 6 August 1976 | Titan III(34)B | VAFB, SLC-4W | SDS F-2 | 380 km | 39315 km | 63.3 deg | |
| OPS 7310 | 1978-075A 10993 | 5 August 1978 | Titan III(34)B | VAFB, SLC-4W | SDS F-3 | 380 km | 39315 km | 63.3 deg | |
| OPS 5805 | 1980-100A 12093 | 13 December 1980 | Titan III(34)B | VAFB, SLC-4W | |||||
| USA-4 | 1984-091A 15226 | 28 August 1984 | Titan III(34)B | VAFB, SLC-4W | SDS F-5A | ||||
| USA-9 | 195-014A 15546 | 8 February 1985 | Titan III(34)B | VAFB, SLC-4W | USA-9 | ||||
| USA-21 | 1987-015A 17506 | 15 February 1987 | Titan III(34)B | VAFB, SLC-4W | SDS F-6 | ||||
Second generation | |||||||||
| USA-40 | 1989-061B 20167 | 2 June 1989 | Space Shuttle Columbia STS-28/Orbus-21S | KSC, LC-39B | N/A | ||||
| USA-67 | 1990-097B 20963 | 15 November 1990 | Space Shuttle Atlantis STS-38/Orbus-21S | KSC, LC-39A | Geosynchronous satellite, deployed along with Prowler and initially misidentified as a Magnum SIGINT spacecraft | ||||
| USA-89 | 1992-086B 22518 | 2 December 1992 | Space Shuttle Discovery STS-53/Orbus-21S | KSC, LC-39A | |||||
| USA-125 | 1996-038A 23945 | 3 July 1996 | Titan IV(405)A | CCAFS, LC-40 | |||||
Third generation | |||||||||
| USA-137 | 1998-005A 25148 | 29 January 1998 | Atlas IIA | CCAFS, SLC-36A | NROL-5 | Capricorn, Molniya orbit | |||
| USA-155 | 2000-080A 26635 | 6 December 2000 | Atlas IIAS | CCAFS, SLC-36A | NROL-10 | Great Bear, geosynchronous satellite at 10° West | |||
| USA-162 | 2001-046A 26948 | 11 October 2001 | Atlas IIAS | CCAFS, SLC-36B | NROL-12 | Aquila, geosynchronous satellite at 144° West | |||
| USA-179 | 2004-034A 28384 | 31 August 2004 | Atlas IIAS | CCAFS, SLC-36A | NROL-1 | Nemesis, Molniya orbit, final Atlas II launch | |||
| USA-198 | 2007-060A 32378 | 10 December 2007 | Atlas V 401 | CCAFS, SLC-41 | NROL-24 | Scorpius, Molniya orbit | |||
| USA-227 | 2011-011A 37377 | 11 March 2011 | Delta IV-M+(4,2) | CCAFS, SLC-37B | NROL-27 | Gryphon, geosynchronous satellite at 10° West, replaced USA-155 | |||
| USA-236 | 2012-033A 38466 | 20 June 2012 | Atlas V 401 | CCAFS, SLC-41 | NROL-38 | Drake, geosynchronous satellite at 144° West, replacement for USA-162 | |||
| USA-252 | 2014-027A 39751 | 22 May 2014 | Atlas V 401 | CCAFS, SLC-41 | NROL-33 | Geosynchronous satellite | |||
| USA-269 | 2016-047A 41724 | 28 July 2016 | Atlas V 421 | CCAFS SLC-41 | NROL-61 | Spike, Geosynchronous orbit, might be a new generation [7] | |||
| USA-279 | 2017-066A 42973 | 15 October 2017 | Atlas V 421 | CCAFS, SLC-41 | NROL-52 | Likely Geosynchronous orbit [8] | |||
STS-28 was the 30th NASA Space Shuttle mission, the fourth shuttle mission dedicated to United States Department of Defense (DoD) purposes, and the eighth flight of Space Shuttle Columbia. The mission launched on August 8, 1989, and traveled 3,400,000 km (2,100,000 mi) during 81 orbits of the Earth, before landing on runway 17 of Edwards Air Force Base, California, on August 13, 1989. STS-28 was also Columbia's first flight since January 1986, when it had flown STS-61-C, the mission directly preceding the Challenger disaster of STS-51-L. The mission details of STS-28 are classified, but the payload is widely believed to have been the first SDS-2 relay communications satellite. The altitude of the mission was between 295 km (183 mi) and 307 km (191 mi).
The KH-11 KENNEN is a type of reconnaissance satellite first launched by the American National Reconnaissance Office (NRO) in December 1976. Manufactured by Lockheed in Sunnyvale, California, the KH-11 was the first American spy satellite to use electro-optical digital imaging, and so offer real-time optical observations.
Delta IV was a group of five expendable launch systems in the Delta rocket family. It flew 45 missions from 2002 to 2024. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV was primarily a launch vehicle for United States Air Force (USAF) military payloads, but was also used to launch a number of United States government non-military payloads and a single commercial satellite.
Vandenberg Space Launch Complex 6 is a launch pad and associated support infrastructure at Vandenberg Space Force Base in California. Construction at the site began in 1966, but the first launch didn't occur until 1995 due to program cancellations and subsequent repurposing efforts.
United Launch Alliance, LLC (ULA) is an American launch service provider formed in December 2006 as a joint venture between Lockheed Martin Space and Boeing Defense, Space & Security. The company designs, assembles, sells and launches rockets, but the company subcontracts out the production of rocket engines and solid rocket boosters.
Magnum was a class of SIGINT spy satellites reportedly operated by the National Reconnaissance Office (NRO) for the United States Central Intelligence Agency (CIA). The program remains classified, and the information that exists is speculative.
Future Imagery Architecture (FIA) was a program awarded to Boeing to design a new generation of optical and radar imaging US reconnaissance satellites for the National Reconnaissance Office (NRO). In 2005 NRO director Donald Kerr recommended the project's termination, and the optical component of the program was finally cancelled in September 2005 by Director of National Intelligence John Negroponte. FIA has been called by The New York Times "perhaps the most spectacular and expensive failure in the 50-year history of American spy satellite projects." Despite the optical component's cancellation, the radar component, known as Topaz, has continued, with four satellites in orbit as of February 2016.
Orion, also known as Mentor or Advanced Orion, is a class of United States spy satellites that collect signals intelligence (SIGINT) from space. Operated by the National Reconnaissance Office (NRO) and developed with input from the Central Intelligence Agency (CIA), eight have been launched from Cape Canaveral on Titan IV and Delta IV launch vehicles since 1995.
USA-200, also known as NRO Launch 28 or NROL-28, is an American signals intelligence satellite, operated by the National Reconnaissance Office. Launched in 2008, it has been identified as the second satellite in a series known as Improved Trumpet, Advanced Trumpet, or Trumpet follow-on; a replacement for the earlier Trumpet series of satellites.
TDRS-5, known before launch as TDRS-E, is an American communications satellite, of first generation, which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW is based on a custom satellite bus which was used for all seven first generation TDRS satellites.
TDRS-3, known before launch as TDRS-C, is an American communications satellite, of first generation, which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW, and is based on a custom satellite bus which was used for all seven first generation TDRS satellites.
TDRS-7, known before launch as TDRS-G, is an American communications satellite, of first generation, which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW as a replacement for TDRS-B, which had been lost in the Challenger accident, and was the last first generation TDRS satellite to be launched.
Discoverer 31, also known as Corona 9024, was an American optical reconnaissance satellite which was launched in 1961. It was a KH-3 Corona''' satellite, based on an Agena-B.
USA-225, also known as the Rapid Pathfinder Prototype (RPP) and NRO Launch 66 (NROL-66), is an American satellite which was launched in 2011. The satellite is being used to perform technology demonstration and development experiments, including advanced dosimeters to characterize the space environment from a 1,200 kilometer low Earth orbit. It is operated by the United States National Reconnaissance Office.
USA-227, known before launch as NRO Launch 27 (NROL-27), is an American communications satellite which was launched in 2011. It is operated by the United States National Reconnaissance Office.
USA-229, known before launch as NRO Launch 34 (NROL-34), is a pair of American signals intelligence satellites which were launched in 2011. They are operated by the United States National Reconnaissance Office.
USA-215, also known as NRO Launch 41 or NROL-41, is an American reconnaissance satellite, operated by the National Reconnaissance Office (NRO). Launched in 2010, it has been identified as the first in a new series of imaging radar satellites, developed as part of the Future Imagery Architecture (FIA) programme, to replace the earlier Lacrosse spacecraft.
USA-234, also known as NRO Launch 25 or NROL-25, is an American reconnaissance satellite, operated by the National Reconnaissance Office. Launched from Vandenberg Air Force Base in 2012, it has been identified as the second radar imaging satellite to be launched as part of the Future Imagery Architecture programme.
USA-184, also known as NRO Launch 22 or NROL-22, is an American signals intelligence satellite, operated by the National Reconnaissance Office. Launched in 2006, it has been identified as the first in a new series of satellites which are replacing the earlier Trumpet spacecraft.
