FLTSATCOM (also FLTSAT) is a satellite communication system of the

U.S. Space Force The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's only independent space force. Along with its sister branch, the U.S. Air Force, the Space ...

which was used for UHF

radio communications Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...

between ships, submarines, airplanes and ground stations of the Navy. Most of the

transponders In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight tran ...

on these satellites were simple repeaters with no authentication or control over what they retransmitted.

FLTSATCOM

Altogether eight satellites were launched from 1978 to 1989 by

Atlas-Centaur The Atlas-Centaur was a United States expendable launch vehicle derived from the SM-65 Atlas D missile. Launches were conducted from Launch Complex 36 at the Cape Canaveral Air Force Station (CCAFS) in Florida. Early development Convair, ...

rockets into geostationary orbit. The system became operational in 1981. The satellites were manufactured by TRW. The solar array of each satellite had a span of over 13.2 m. A special characteristic was a UHF transmit antenna reflector 4.9 m in diameter. Each satellite had 12 transponders, which worked in the UHF range from 240 - 400 megahertz. Additionally FLTSATCOM 7 and 8 included an experimental EHF transponder built by

Lincoln Laboratory The MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense federally funded research and development center chartered to apply advanced technology to problems of national security. Research and de ...

intended to test the

MILSTAR Milstar (Military Strategic and Tactical Relay) is a constellation of military communications satellites in geosynchronous orbit, which are operated by the United States Space Force, and provide secure and jam-resistant worldwide communications ...

ground terminals. The first seven satellites each had a launch mass of 1884 kg and the remaining two were 2310 kg, with the additional mass due to the EHF payload module. The fifth satellite reached geosynchronous orbit, but had severely limited utility due to damage to the solar arrays and antennas. The failure was attributed to explosive delamination of the fiberglass

honeycomb A honeycomb is a mass of hexagonal prismatic wax cells built by honey bees in their nests to contain their larvae and stores of honey and pollen. Beekeepers may remove the entire honeycomb to harvest honey. Honey bees consume about of honey ...

fairing during flight. The inside wall of the fairing extensively damaged one of the solar arrays, and bent the transmit antenna mast which prevented the antenna from deploying fully. Flight 7 was launched out of sequence after a launch failure of a Delta mission carrying the

GOES-G GOES-G was a weather satellite to be operated by the National Oceanic and Atmospheric Administration. The satellite was designed to sense and monitor meteorological conditions from a geostationary orbit, intended to replace GOES-5 and provide c ...

weather satellite grounded the entire US launch fleet weeks prior to the scheduled launch of F-6. By the time the Delta mishap investigation concluded there was no risk to the Atlas-Centaur system, F-7 was ready to launch and the system managers elected to swap missions to avoid delaying EHF system testing. Flight 6 was destroyed in a launch failure. The Atlas-Centaur was launched on March 26, 1987 into a heavy overcast with light rain. 51 seconds into the flight, the Atlas was struck by lightning and the resulting EMP changed a value in the guidance computer's core memory, causing the rocket to yaw and break apart from aerodynamic stress. As a result of this mishap, NASA and the Air Force re-emphasised and clarified the original weather guidelines developed after the Apollo 12 on-stand lightning strike for all future launches. In the late 1990s, FLTSATCOM satellites were gradually replaced by the UFO satellites. FLTSAT flights 7 and 8 continue to provide UHF communications. Presently, FLTSATCOM 7 and FLTSATCOM 8 have been used for repeating UHF Satcom transmissions by unauthorized radio users particularly in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, including criminals, illegal loggers, truckers and individuals located in remote areas. This has been met with limited law enforcement action.

Launches

References

* Globalsecurity.org
FLTSAT
* {{cite web , work= NASA

Mission and Spacecraft Library Mission and Spacecraft Library (MSL) is a reference web site, maintained by NASA, containing information about satellites. It contains a catalog of several hundreds of satellites from different countries. The site was founded by Jet Propulsion L ...

, url= http://msl.jpl.nasa.gov/QuickLooks/fltsatcomQL.html , title= QuickLooks FLTSATCOM , archive-url= https://web.archive.org/web/20060929054027/http://msl.jpl.nasa.gov/QuickLooks/fltsatcomQL.html , archive-date= 29 September 2006 , url-status= dead , publisher= NASA JPL * Federation of American Scientists
FLTSATCOM System
* FLTSATCOM Flight 6 Launch Book - TRW Electronics and Defense Sector, April 1986 Military communications of the United States Equipment of the United States Space Force ja:アメリカ軍の衛星通信#FLTSATCOM

FLTSATCOM

Launches

See also

References