Defense Satellite Communications System Mission As the legacy backbone of the U.S. military's global satellite communications capabilities, the Defense Satellite Communications System constellation provides nuclear-hardened, anti-jam, high-data rate, long-haul communications to users worldwide. DSCS supports: the defense communications system, the Army's ground mobile forces, the Air Force's airborne terminals, Navy ships at sea, the White House Communications Agency, the State Department and other users. U.S. Strategic Command has overall responsibility for DSCS. Background The first DSCS III satellite was launched in October 1982. In all, DSCS III successfully launched 14 operational satellites, of which 8 satellites are still operational and continue to be used in various capacities, from operational communications in Southwest Asia to research and development of ground-based support capabilities. The Space and Missile Systems Center's MILSATCOM Systems Directorate is responsible for the DSCS Space Segment under contract with Lockheed Martin Space Systems Company in Sunnyvale, Calif., who sustains the satellite constellation. Description DSCS III satellites support globally distributed Department of Defense and national security users. The final four of 14 satellites received Service Life Enhancement Program modifications. These changes provide 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 MHz 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. Part of MILSATCOM's Logistics and Operations Support Division, the DSCS III system provides the capabilities needed for effective implementation of worldwide military communications. It can adapt rapidly to dynamic operating conditions and perform under stressed environments. DSCS III operates with large or small terminals, and with Code Divisional Multiple Access, Frequency Division Multiple Access or Time Division Multiple Access multiplexing. DSCS's independent channels group users by operational needs or geographical location by allocating receiver sensitivity and transmitter power, thus providing maximum efficiency. General Characteristics Primary Function: High-capacity military communications satellite Primary Contractor: Lockheed Martin Payload: 6-channel SHF transponded system. Single Channel Transponder (UHF/X, crossband) Antennas: Wideband multi-beam and two earth coverage receive antennas; two transmit multi-beam, gimbaled dish, and two earth coverage antennas Capability: Up to 200 Mbps