United States Space Surveillance Network
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The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of United States Space Command and operated by the United States Space Force and its functions are:
- Predict when and where a Earth's atmosphere;
- Prevent a returning space object, which to radar looks like a missile, from triggering a false alarm in missile-attack warning sensors of the U.S. and other countries;
- Chart the present position of space objects and plot their anticipated orbital paths;
- Detect new artificial objects in space;
- Correctly map objects traveling in Earth orbit;
- Produce a running catalog of artificial space objects;
- Determine ownership of a re-entering space object;
The Space Surveillance Network includes dedicated, collateral, and contributing electro-optical, passive radio frequency (RF) and radar sensors. It provides space object cataloging and identification, satellite attack warning, timely notification to U.S. forces of satellite fly-over, space treaty monitoring, and scientific and technical intelligence gathering. The continued increase in satellite and orbital debris populations, as well as the increasing diversity in launch trajectories, non-standard orbits, and geosynchronous altitudes, necessitates continued modernization of the SSN to meet existing and future requirements and ensure their cost-effective supportability.[1]
SPACETRACK also developed the systems interfaces necessary for the command and control, targeting, and damage assessment of a potential future U.S.
History
1957–1963
The first formalized effort by the US government to catalog satellites occurred at Project Space Track, later[when?] known as the National Space Surveillance Control Center (NSSCC), located at Hanscom Field in Bedford, Massachusetts. The procedures used at the NSSCC were first reported in 1959 and 1960 by Wahl,[2] who was the technical director of the NSSCC. In 1960, under Project Space Track, Fitzpatrick and Findley developed detailed documentation of the procedures used at the NSSCC.[3] Project Space Track began its history of satellite tracking from 1957–1961.
Early Space Track observations of satellites were collected at more than 150 individual sites, including radar stations,
Missile Warning and Space Surveillance in the Eisenhower Years
The launch of Sputnik 1 by the Soviet Union led to a US government perceived need to better track objects in space using the Space Tracking System. The first US system, Minitrack, was already in existence at the time of the Sputnik launch, but the US quickly discovered that Minitrack could not reliably detect and track satellites. The US Navy designed Minitrack to track the Vanguard satellite, and so long as satellites followed the international agreement on satellite transmitting frequencies, Minitrack could track any satellite. However, the Soviets chose not to use the international satellite frequencies. Thus, a major limitation of this system became visible. Minitrack could not detect or track an uncooperative or passive satellite.[4]
Concurrent[citation needed] with Minitrack was the use of the Baker-Nunn satellite tracking cameras. These systems used modified Schmidt telescopes of great resolution to photograph and identify objects in space. The cameras first became operational in 1958 and eventually operated at sites worldwide. At their peak, the Air Force ran five sites, the Royal Canadian Air Force ran two, and the Smithsonian Institution's Astrophysics Observatory operated a further eight sites. The Baker-Nunn system, like Minitrack, provided little real-time data and was additionally limited to night-time, clear weather operations.[4]
Beyond the problems in acquiring data on satellites, it became obvious that the US tracking network would soon be overwhelmed by the tremendous number of satellites that followed Sputnik and Vanguard. The amount of satellite tracking data accumulated required creation or expansion of organizations and equipment to sift through and catalog the objects. The need for real-time detection and tracking information to deal with Soviet satellite launches led on 19 December 1958 to ARPA's implementation of Executive Order 50-59 to establish a spacetrack network. This spacetrack network, Project Shepherd, began with the Space Track Filter Center at Bedford, Massachusetts, and an operational space defense network (i.e., a missile warning network). ARDC took up the spacetrack mission in late 1959 and in April 1960 set up the Interim National Space Surveillance Control Center at Hanscom Field, Massachusetts, to coordinate observations and maintain satellite data. At the same time, DOD designated the Aerospace Defense Command (ADCOM), formerly Air Defense Command, as the prime user of spacetrack data. ADCOM formulated the first US plans for space surveillance.[4]
During the years that intercontinental ballistic missiles were developing as frontline weapon systems, numerous missile detection and warning sensors were being experimented with and fielded as operational sensors and most of these contributed satellite observation data at one time or another. Many have been overlooked by current histories and additional research is merited. Among these were two Trinidad detection and tracking radars;
Air Force Space Surveillance System
The
The Satellite Detection and Reconnaissance Defense (the former designation of the NSSS) reached initial operating capability in 1961. The role of the "fence" grew. The system detected space objects from new launches, maneuvers of existing objects, breakups of existing objects, and provided data to users from its catalog of space objects. Orbital parameters of more than 10,000 objects were maintained in this catalog—which has now gained usage by NASA, weather agencies, and friendly foreign agencies. The information is essential to computing the collision avoidance information to de-conflict launch windows with known orbiting space objects.
The
US Space Catalog
The United States Department of Defense (DoD) has maintained a database of satellite states since the launch of the first Sputnik in 1957, known as the Space Object Catalog, or simply the Space Catalog. These satellite states are regularly updated with observations from the Space Surveillance Network, a globally distributed network of interferometer, radar and optical tracking systems. By the year 2001, the number of cataloged objects was nearly 20,000.[8][9][10]
Different
NASA maintains civilian databases of GP orbital elements, also known as NASA or
Shemya and Diyarbakir Radar Sites
AN/FPS-17 and AN/FPS-80 radars were placed at Shemya Island in the Aleutian Islands off the Alaskan coast in the 1960s to track Soviet missile tests and to support the Air Force Spacetrack System. In July 1973, Raytheon won a contract to build a system called "Cobra Dane" on Shemya. Designated as the AN/FPS-108, Cobra Dane replaced AN/FPS-17 and AN/FPS-80 radars. Becoming operational in 1977, Cobra Dane also had a primary mission of monitoring Soviet tests of missiles launched from southwest Russia aimed at the Siberian Kamchatka peninsula. This large, single-faced, phased-array radar was the most powerful ever built.
The FPS-80 was a tracking radar and the FPS-17 was a detection radar for Soviet missiles. Both were part of the Ballistic Missile Early Warning System (
The
AN/FPS-17
With the Soviet Union apparently making rapid progress in its rocket program, in 1954 the United States began a program to develop a long range surveillance radar. General Electric Heavy Military Electronics Division (HMED) in
The FPS-17 antenna featured a fixed parabolic torus section reflector that typically stood 175 feet (53 m) high and 110 feet (34 m) wide and was illuminated by an array of radar feed horns placed in front of it. The transmitters operated in the
AN/FPS-79
The original FPS-79 antenna at Diyarbakir had a unique feature which enhanced its Spacetrack usefulness. A variable-focus feed horn provided a wide beam for detection and a narrow beamwidth for tracking. That antenna was replaced by a new antenna and pedestal in 1975. Pulse compression was used to improve both the gain and resolution of the 35-foot (11 m) dish antenna. Steering was mechanical; the FPS-79 had a range of 24,000 miles (39,000 km). The radar site closed in 1997.
After circling the Earth in an apparently dormant state for 9 months, on November 13, 1986 the
Although the debris cloud did not pass over the
Blue Nine and Blue Fox
Blue Nine refers to a project which produced the AN/FPS-79 Tracking Radar Set built by General Electric, used with the 466L Electromagnetic Intelligence System (ELINT); US Air Force. Blue Fox refers to a modification of the AN/FPS-80 tracking radar to the AN/FPS-80(M) configuration. Shemya, AK, 1964. Both of these systems incorporated GE M236 computers.
AN/FPS-80
A 60-foot dish mechanical tracking radar built by General Electric. Deployed at Shemya Island, Alaska, as a UHF radar and upgraded to L-Band in 1964. Used as tracker radar for Spacetrack network measurements once target detected. Principally used for intelligence purposes to track Russian missiles. The advanced FPS-108 Cobra Dane phased array radar replaced the FPS-17 and FPS-80 radars in 1977.
Space Surveillance Network
The command accomplishes these tasks through its Space Surveillance Network (SSN) of U.S. Army, Navy and Space Force operated, 30+ ground-based radars and optical telescopes worldwide, plus 6 satellites in orbit.[19]
As of June 23, 2019[update], the catalog built using SSN data listed 44,336 objects including 8,558 satellites launched into orbit since 1957.[20] 17,480 of them were actively tracked while 1,335 were lost.[21] The rest have re-entered Earth's turbulent atmosphere and disintegrated, or survived re-entry and impacted the Earth. The SSN typically tracks space objects which are 10 centimeters in diameter (baseball size) or larger.[22]
The Space Surveillance Network has numerous sensors that provide data. They are separated in three categories: dedicated sensors, collateral sensors and auxiliary sensors. Both the dedicated and collateral sensors are operated by the
- Dedicated sensors
- Ground-based Electro-Optical Deep Space Surveillance(GEODSS) sites
- Space Surveillance Telescope (SST)
- MOSS - an Electro-Optical (E-O) surveillance system located at the Moron Air Base, Spain
- GLOBUS IIradar
- AN/FPS-85 Space Track Radar
- AN/FPS-133 Air Force Space Surveillance System, also known as the Space Fence and its replacement Space Fence
- Midcourse Space Experiment (MSX) / Space Based Visible (SBV) satellites
- Collateral sensors
- Maui Space Surveillance System (MSSS) and Advanced Electro-Optical System (AEOS) telescope, co-located with a GEODSS station in Maui, Hawaii
- Millstone Hill Radar
- ALTAIR and ALCOR radars at the Ronald Reagan Ballistic Missile Defense Test Site, Kwajalein Atoll
- Ascension Range Radar, locate at the Eastern Spacelift Range
- Ground-Based Radar Prototype (GBR-P), located Ronald Reagan Ballistic Missile Defense Test Site, Kwajalein Atoll
- Auxiliary sensors
- AN/FPS-132 Upgraded Early Warning Radar(UEWR) system of system, deployed at multiple sites
- AN/FPS-108 Cobra Dane
- Perimeter Acquisition Radar Characterization System(PARCS)
Ground-based Electro-Optical Deep Space Surveillance
Ground-based Electro-Optical Deep Space Surveillance, or GEODSS, is an optical system that uses
There are three operational GEODSS sites that report to the
- Socorro, New Mexico 33°49′02″N 106°39′36″W / 33.8172°N 106.6599°W
- Maui, Hawaii 20°42′32″N 156°15′28″W / 20.7088°N 156.2578°W
- Diego Garcia, British Indian Ocean Territory 7°24′42″S 72°27′08″E / 7.41173°S 72.45222°E.
A site at Choe Jong San, South Korea was closed in 1993 due to nearby smog from the town, weather and cost concerns. Originally, the fifth GEODSS was planned to be operated from a site in Portugal, but this was never built.
Moron Optical Space Surveillance (MOSS), a transportable 22-inch aperture telescope that contributed to the GEODSS system was operational at Morón Air Base, Spain 37°10′12″N 5°36′32″W / 37.170°N 5.609°W from 1997 to 2012.
GEODSS tracks objects in
Space Based Visible (SBV) Sensor
The SSN included one spaceborne sensor, the space-based visible (SBV) sensor, carried into orbit aboard the Midcourse Space Experiment (MSX) satellite launched by the Ballistic Missile Defense Organization in 1996. It was retired from service on June 2, 2008.[23]
The Space Based Space Surveillance (SBSS) pathfinder satellite now performs the mission previously handled by the MSX SBV.
The Canadian military satellite Sapphire, launched in 2013, also contributes data to the SSN.[24]
Civil services
The USSPACECOM is primarily interested in the active satellites, but also tracks space debris. As the number of space debris and the value of satellites in space grew it has become important to protect civil economic activity and help satellite operators avoid collisions with debris. In 2010, USSTRATCOM was given authority to provide SSA (Space Situational Awareness) services to commercial and foreign actors.[19] As of 2019 the following services are provided: positional data of all tracked objects, conjunction assessment, disposal/end-of-life support and more through the space-track.org website.[25]
See also
- Air Force Space Surveillance System
- Air Force Maui Optical and Supercomputing observatory
- Space Situational Awareness Programme, the European Space Agency's near-Earth object and space debris tracking programme
- Kessler syndrome
- Satellite watching
- Space debris
- Russia :
- Krona space object recognition station and Krona-N, Russian telescope- and radar-based space surveillance facilities
- Okno and Okno-S, Russian telescope-based space surveillance facilities
- Main Space Intelligence Centre, the headquarters of the Russian military's space surveillance network, SKKP
References
- ISBN 978-0-688-31561-0.
- ^ Wahl, E[berhart] W., Program Development in Orbital Computation at the U.S. National Space Surveillance Control Center. [Proceedings of the Second Symposium (International) on Rockets and Astronautics]. [Tokyo: May 1960.]
- ^ ISSN 0731-5090.
- ^ a b c Muolo, Maj Michael J. (December 1993). Space Handbook - A War Fighter's Guide to Space (Report). Vol. One. Maxwell Air Force Base: Air University Press.
- ^ Glaus, Stacy. "End of an era for AFSSS". Peterson Air Force Base. U.S. Air Force. Archived from the original on 24 March 2014. Retrieved 24 March 2014.
- ^ "Good (space) fences make for good (orbital) neighbors - SpaceNews.com". SpaceNews.com. 2016-09-19. Retrieved 2017-01-01.
- ^ "Space Fence · Lockheed Martin". www.lockheedmartin.com. Retrieved 2017-01-01.
- ^ a b c Neal, H. L.; S.L. Coffey; S.H. Knowles (1997). "Maintaining the Space Object Catalog with Special Perturbations". Astrodynamics. v.97 (Part II). Sun Valley, ID: AAS/AIAA: 1349–1360.
- ISBN 1-881883-12-4.
- ^ Hoots, Felix R.; Ronald L. Roehrich (December 1980). "SPACETRACK REPORT NO. 3 - Models for Propagation of NORAD Element Sets". Adc/Do6. Peterson AFB: Project Spacetrack Reports, Office of Astrodynamics, Aerospace Defense Center.
- ^ a b c Progress In Defense and Space, A History of the Aerospace Group of the General Electric Company, Major A. Johnson, 1993, pp262, 287-289.
- ^ a b A Fiery Peace in a Cold War: Bernard Schriever and the Ultimate Weapon, Neil Sheehan, 2009, pp301-311.
- ^ a b "The Diyarbakir Radar", Stanley G. Zabetakis & John F. Peterson, 1964. Studies in Intelligence, Fall 1964 edition, pages 41-47. Declassified.
- ^ Forty Years of Research and Development at Griffiss Air Force Base, Rome Air Development Center, 1992.
- ISBN 978-0-7106-2855-8.
- ^ a b NRL Memorandum Report 1637, "Information on Over-the-Horizon Radar", Part VI, 13 August 1965. Declassified.
- ^ "Radar Development at Lincoln Laboratory: An Overview of the First Fifty Years", William P. Delaney and William W. Ward, Vol.12, No. 2, 2000 Lincoln Laboratory Journal, pp147-166.
- ^ Johnson, N. L. (1989). "Preliminary analysis of the Fragmentation of the SPOT 1 Ariane Third Stage". Progress in Astronautics and Aeronautics. 121. Washington, DC: AIAA: 41–47.
- ^ a b "US Policy and Capabilities on SSA" (PDF). Secure World Foundation. 24 January 2019. Retrieved 3 October 2019.
- ^ Kelso, T.S. "SATCAT Boxscore". CelesTrak. Archived from the original on July 10, 2018. Retrieved June 23, 2019.
- ^ Kelso, T.S. "TLE History Statistics". CelesTrak. Retrieved June 23, 2019.
- 18 SPCSmaintains in the catalog.
- ^ Amy Butler (2008). "Space-Based Visible Sensor Ceases Ops". Aviation Week. Retrieved November 21, 2008.[permanent dead link]
- ^ "Canada's DND Sapphire satellite completes commissioning". MDA. Retrieved 13 November 2014.
- ^ "SSA Sharing & Orbital Data Requests". Space-Track.org. Retrieved 3 October 2019.
External links
- The Space-Track website
- U.S. Strategic Command Space Surveillance
- Orbital Debris Quarterly News information on some of the latest events in orbital debris research.
- "Air Force Fact Sheet". Archived from the original on 2012-07-21. Retrieved 2010-06-17.
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