A DSCS 3 satellite during pre-flight testing at manufacturer facilities. Photo: Lockheed Martin

As the backbone of the US military's global satellite communications capabilities, the DSCS constellation provides nuclear-hardened, antijam, high data rate, long-haul, communications to users worldwide.

DSCS serves all DoD branches in a worldwide network coordinated by the Defense Information Systems Agency (DISA). DSCS supports the defense communications system, the Army's ground mobile forces, Navy ships at sea, the White House Communications Agency, the State Department, and special users. Overall DSCS responsibility resides in US Space Command.

The DSCS 3 satellites support globally distributed Department of Defense (DoD) and national security users. The final four satellites have been upgraded with the Service Life Enhancement Program (SLEP) modifications. These 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 500MHz bandwidth. Three receive and five transmit antennas provide selectable options for Earth coverage, area coverage, and/or spot beam coverage. A special purpose (AFSATCOM) single-channel transponder is also on board.

The DSCS 3 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 3 operates with large or small terminals, and with CDMA, DFDMA, or TDMA. Its independent channels can provide resources on command, grouping users by their operational needs or geographical location, and allocating receiver sensitivity and transmitter power among them for maximum efficiency.

The first DSCS 3 satellite was launched in October 1982. The on-orbit DSCS constellation is comprised of five DSCS 3 satellites in geosynchronous, geostationary orbit. B11 (DSCS 3 SLEP), launched in October 2000 and now operating in the Eastern Atlantic, is the newest DSCS satellite on orbit.

Lockheed Martin Space Systems Company in Sunnyvale, CA is responsible for DSCS satellite design, manufacture, and test under contract to the US Air Force. Fourteen DSCS 3 satellites have been built, with twelve on orbit and two yet to launch.

The MILSATCOM Joint Program Office of Space and Missile Systems Center (SMC), Los Angeles AFB, California, is responsible for development, acquisition, and sustainment of the DSCS Space Segment.

General characteristics

• Primary function: High capacity military communications satellite
• Primary contractor: Lockheed Martin Space Systems Company
• Dry weight: Approx. 2,000 lbs
• Orbit altitude: 22,300 miles
• Payload: Ten 50-watt X-band Travelling Wave Tube Amplifiers
• Antennas: Wideband multibeam and two earth coverage receive antennas; two transmit multibeam, gimbaled dish, and two earth coverage antennas
• Capability: Up to 200 Mbps
• Unit cost: Approx. $200 million
• Survivability: Nuclear tested
• Launch Vehicle: Boeing Delta 4 Medium EELV
• Constellation: Five primary, five residual satellites