[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/en\/wiki8\/defense-satellite-communications-system-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/en\/wiki8\/defense-satellite-communications-system-wikipedia\/","headline":"Defense Satellite Communications System – Wikipedia","name":"Defense Satellite Communications System – Wikipedia","description":"before-content-x4 From Wikipedia, the free encyclopedia after-content-x4 Defense satellite communications project after-content-x4 Illustration of the DSCS III satellite The Defense","datePublished":"2015-02-23","dateModified":"2015-02-23","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/en\/wiki8\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/en\/wiki8\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/91\/DSCS-3_1.jpg\/300px-DSCS-3_1.jpg","url":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/91\/DSCS-3_1.jpg\/300px-DSCS-3_1.jpg","height":"232","width":"300"},"url":"https:\/\/wiki.edu.vn\/en\/wiki8\/defense-satellite-communications-system-wikipedia\/","wordCount":2189,"articleBody":"     (adsbygoogle = window.adsbygoogle || []).push({});before-content-x4From Wikipedia, the free encyclopedia       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Defense satellite communications project         (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Illustration of the DSCS III satelliteThe Defense Satellite Communications System (DSCS)[1] is a United States Space Force satellite constellation that provides the United States with military communications to support globally distributed military users.  Beginning in 2007, DSCS is being replaced by the Wideband Global SATCOM system.  A total of 14 DSCS-III satellites were launched between the early 1980s and 2003.  Two satellites were launched aboard the Space Shuttle Atlantis in 1985 during the STS-51-J flight.  As of 14 September 2021, six DSCS-III satellites were still operational.[2] DSCS operations are currently run by the 4th Space Operations Squadron out of Schriever Space Force Base.Table of ContentsBackground[edit]DSCS II[edit]DSCS III[edit]DSCS III Spacecraft[edit]Image gallery[edit]See also[edit]References[edit]External links[edit]Background[edit]DSCS went through three major phases\u00a0\u2014 IDCSP (Interim Defense Communication Satellite Program), DSCS-II, and DSCS-III. Since the first launch, DSCS has been the “workhorse” of military satellite communications. All DSCS III satellites have exceeded their 10-year design life. The National Science Foundation use the DSCS satellites to provide additional bandwidth to Amundsen\u2013Scott South Pole Station and McMurdo Station on Ross Island on the continent of Antarctica.[3]       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4  Artist’s rendering of a Transtage deploying IDSCP satellitesIn April 1960, the Advanced Research Projects Agency (ARPA) began work on the Advent program, which was intended to deliver a military communication satellite. The design concept proved too advanced for the technology of the time, and the program was cancelled in May 1962. The Initial Defense Communications Satellite Program (IDCSP) was one of two recommended follow up approaches to deliver a working satellite.Philco (now Ford Aerospace) was contracted for the work. The IDCSP delivered a simple, spin-stabilized satellite placed into a sub-synchronous orbit that did not require station-keeping or active altitude control. The capacity was approximately 1 Mbit\/s digital data.The first launch of 7 satellites was conducted in June 1966. The system was declared operational with the 1968 launch and renamed to Initial Defense Satellite Communication System (IDSCS).[4]A total of 34 IDSCS satellites were built, with 8 lost in a launch failure in August 1966.[5]DSCS II[edit]Illustration of a DSCS II satelliteOverview of DSCS II, circa 1977DSCS II, developed under Program 777[6] provided secure voice and data transmission for the United States Armed Forces. The program was managed by the Defense Communications Agency (DCA), now the Defense Information Systems Agency.The space vehicles were spin stabilized with a de-spun antenna platform. The body was mounted with solar cells, which produced 535 watts. Three NiCd batteries provided electrical power and it was supported by a hydrazine propulsion subsystem.The communications payload included two 20-watt X band channels. The transponders were supported by steerable narrow beam antennas and drive mechanism for communications privacy.The first DSCS II launch was in 1971.[7]DSCS III[edit]On 12 December 1975 research and development contracts were awarded to General Electric and Hughes Aircraft Company[8] to begin DSCS III design studies, with the first Block 1 launch on 30 October 1982.[4]DSCS III satellites support globally distributed Department of Defense (DoD) and national security users. The final 4 of 14 satellites received Service Life Enhancement Program (SLEP) modifications. These changes provided substantial capacity improvements through higher power amplifiers, more sensitive receivers, and additional antenna connectivity options. The DSCS communications payload includes six independent Super High Frequency (SHF) transponder channels that cover a 500\u00a0MHz bandwidth. Three receive and five transmit antennas provide selectable options for Earth coverage, area coverage and\/or spot beam coverage. A special purpose single-channel transponder is also on board.[9]DSCS III Spacecraft[edit]Spacecraft NameOther DesignationLaunch date\/time (UTC)NSSDCA\/COSPAR IDRocketStatus\/RemarksDSCS III-01DSCS III-A11982-10-30, 04:05:001982-106BTitan 34DDecommissioned\/Launched with DSCS II-16USA-11DSCS III-B41985-10-03, 15:15:301985-092BSpace Shuttle AtlantisDecommissioned[10]USA-12DSCS III-B51985-10-03, 15:15:301985-092CSpace Shuttle AtlantisDecommissioned[10]USA-43DSCS III-06 or DSCS III-A21989-09-04, 05:54:001989-069ATitan 34DDecommissioned[10]USA-44DSCS III-071989-09-04, 05:54:001989-069BTitan 34DUSA-78DSCS III-081992-02-10, 00:41:001992-006AAtlas IIDecommissioned[10]USA-82DSCS III-091992-07-02, 21:54:001992-037AAtlas IIDecommissioned[10]USA-93DSCS III-101993-07-19, 22:04:001993-046AAtlas IIDecommissioned[10]USA-97DSCS III-111993-11-28, 23:40:001993-074AAtlas IIUSA-113DSCS III-B71995-07-31, 23:30:001995-038AAtlas IIADecommissioned on 9 December 2022.[11]USA-134DSCS III-B131997-10-25, 00:46:001997-065AAtlas IIAOperational[10]USA-148DSCS III-B112000-01-25, 01:03:00 UTC2000-001AAtlas IIAOperational[10]USA-167DSCS III-A32003-03-11, 00:59:00 UTC2003-008ADelta IVOperational[10]USA-170DSCS III-B62003-08-29, 23:13:00 UTC2003-040ADelta IVOperational[10]Image gallery[edit]See also[edit]References[edit]External links[edit]6       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4"},{"@context":"http:\/\/schema.org\/","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki8\/#breadcrumbitem","name":"Enzyklop\u00e4die"}},{"@type":"ListItem","position":2,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki8\/defense-satellite-communications-system-wikipedia\/#breadcrumbitem","name":"Defense Satellite Communications System – Wikipedia"}}]}]