U.s. Space Surveillance Network
Space Surveillance Network)
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The United States Space Surveillance Network is a critical part of United States Strategic Command's (USSTRATCOM) mission and involves detecting, tracking, cataloging and identifying man-made objects orbiting Earth, i.e. Space surveillance accomplishes the following:
Predict when and where a decaying space object will re-enter the 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 man-made objects in space;
Produce a running catalog of man-made space objects;
Determine which country owns a re-entering space object;
Inform NASA whether or not objects may interfere with the space shuttle or satellites and International Space Station orbits.
The SPACETRACK program represents a worldwide Space Surveillance Network (SSN) of dedicated, collateral, and contributing electro-optical, passive radio frequency (rf) and radar sensors. The SSN is tasked to provide 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.
SPACETRACK also developed the systems interfaces necessary for the command and control, targeting, and damage assessment of a potential future U.S.
There is an Image Information Processing Center and Supercomputing facility at the Air Force Maui Optical Station (AMOS). The resources and responsibility for the HAVE STARE Radar System development were transferred to SPACETRACK from an intelligence program per Congressional direction in FY93.
1957–1963
The first formalized effort to catalog satellites occurred at 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 by Wahl, who was the technical director of the NSSCC. In 1960, under Project SPACETRACK, Fitzpatrick and Findley developed detailed documentation of the procedures used at the NSSCC.
Observation of satellites was performed at more than 150 individual sites.
Contributions came from radars, Baker–Nunn cameras, telescopes, radio receivers, and the Moon Watch participants. The observations were transferred to the NSSCC by teletype, telephone, mail, and personal messenger.
There a duty analyst reduced the data and determined corrections that should be made to the orbital elements before they were used for further prediction. After this analysis, these corrections were fed into an IBM-709 computer that computed the updated orbital data.
These updated orbital data were then used in another phase of the same computer program to yield the geocentric ephemeris. From the geocentric ephemeris, three different products were computed and sent back to the observing stations for their planning of future observing opportunities.
Missile Warning and Space Surveillance in the Eisenhower Years
The launch of Sputnik I triggered a need for tracking of 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.
Minitrack could not detect or track an uncooperative or passive satellite.
Concurrent 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 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 limited to night, clear weather operations.
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 huge amounts of satellite tracking data accumulated required creation or expansion of organizations and equipment just to sift through and catalog the objects. 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.(96) 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.
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. The orbital elements and their associated partial derivatives are expressed as series expansions in terms of the initial conditions of these differential equations.
Assumptions must be made to simplify these analytical theories, such as truncation of the Earth’s gravitational potential to a few zonal harmonic terms. Increased accuracy of GP theory usually requires significant development efforts.
NASA maintains civilian databases of GP orbital elements, also known as NASA or NORAD two-line elements.
In July 1973, Raytheon won a contract to build a system called "Cobra Dane" on Shemya Island in the Aleutian Islands off the Alaskan coast. 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.
These radars were closed in the 1970s.
The Pirinclik (near Diyarbakir, Turkey) intelligence collection radar consisted of one detection radar and one tracking radar. In addition, the Pirinclik radar was the only 24-hour-per-day eastern hemisphere deep space sensor.
It replaced an older system of six 20 inch (half meter) Baker-Nunn cameras using photographic film.
There are three operational GEODSS sites that report to the 21st Operations Group:
Socorro, New Mexico 33°49′02″N 106°39′36″W / 33.8172°N 106.6599°W / 33.8172; 106.6599
Maui, Hawaii20°42′32″N 156°15′28″W / 20.7088°N 156.2578°W / 20.7088; 156.2578
Diego Garcia, British Indian Ocean Territory7°24′42″S 72°27′08″E / 7.41173°S 72.45222°E / 7.41173; 72.45222.
A site at Choe Jong San, South Korea was closed in 1993 due to nearby smog from the town, weather and cost concerns.
A mobile telescope that contributes to the GEODSS system is located at Morón Air Base, Spain 37°10′12″N 5°36′32″W / 37.170°N 5.609°W / 37.170; 5.609
GEODSS tracks objects in deep space, or from about 3,000 mi (4,800 km) out to beyond geosynchronous altitudes. This sensitivity, and sky background during daytime that masks satellites reflected light, dictates that the system operate at night.
Distant Molniya orbiting satellites are often detected in elliptical orbits that surpass the moon and back (245,000 miles out).