As the backbone of the U.S. military's global satellite communications capabilities, the Defense Satellite Communications System (DSCS) 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 special users. Overall DSCS responsibility resides in the United States Strategic Command.

The Defense Satellite Communications Systems (DSCS) is an important part of the comprehensive plan to support globally distributed military users.

Currently, two Phase II and eight Phase III DSCS satellites orbit the earth at an altitude of more than 23,000 miles. DSCS III also carries a single channel transponder used for disseminating emergency action and force direction messages to nuclear capable forces. Each satellite utilizes six super high frequency transponder channels capable of providing worldwide secure voice and high rate data communications.

The system is used for high priority communication such as the exchange of wartime information between defense officials and battlefield commanders. The military also uses DSCS to transmit space operations and early warning data to various systems and users.

The first of the operational DSCS II satellites was launched in 1971. Their two-dish antennas concentrate electronic beams on small areas of the Earth's surface, but have limited adaptability in comparison to the newer DSCS III.

The Air Force began launching the more advanced DSCS IIIs in 1982. The system is built with single, multiple-beam antennas that provide more flexible coverage than its predecessors. The single steerable dish antenna provides an increased power spot beam which can be tailored to suit the needs of different size user terminals. DSCS III satellites can resist jamming and are expected to operate twice as long as DSCS IIs.

DSCS users operate on the ground, at sea or in the air. A special-purpose (AFSATCOM) single channel transponder is also on board the DSCS III satellite. Members of Air Force Space Command units, the 50th Space Wing's 3rd Space Operations Squadron at Falcon Air Force Base, Colo., and 5th Space Operations Squadron at Onizuka Air Force Station, Calif., provide command and control for all DSCS systems.

Air Force Materiel Command's Space and Missile Center at Los Angeles Air Force Base, Calif., is responsible for development and acquisition of DSCS satellites and ground systems.

DSCS Specifications

Weight: DSCS II -- 1,350 pounds DSCS III -- 2,580 pounds

Orbit Altitude: Both: 23,230 miles

Power Plant: DSCS II -- solar arrays generating 535 watts decreasing to 358 watts after five years. DSCS III -- solar arrays generating 1,100 watts, decreasing to 837 watts after five years

Dimensions: DSCS II -- cylindrical body is 9 feet in diameter, 6 feet high;13 feet high with antennas deployed DSCS III -- rectangular body is 6 feet x 6 feet x 7 feet; 38-foot span with solar arrays deployed

Launch Vehicle: On-orbit DSCS II and III -- Titan 34D, space shuttle Future Systems: Atlas II

Primary Contractor: DSCS II -- TRW DSCS III -- Martin Marietta Astro Space

(Current as of May 1995)


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Defense Satellite Communications System