Defense Satellite Communications System

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The Defense Satellite Communications System provides the United States with military communications to support globally distributed military users.

1 Background
2 Initial Defense Satellite Communications System (IDSCS)
3 DSCS II
4 DSCS III
- 4.1 DSCS III Service Life Enhancement Program (SLEP)
5 References
6 See Also

[edit] Background

DSCS went though three major phases. Since the first launch DSCS has been the "workhorse" of military satellite communications. DSCS III satellites currently exceed their 10-year design life.

[edit] Initial Defense Satellite Communications System (IDSCS)

The DSCS program began in 1966 with the launch of the first 8 satellites of this constellation.

[edit] DSCS II

DSCS II provided secure voice and data communications for the U.S. military. The program was managed by the Defense Communications Agency (DCA), now DISA.

The space vehicles were spin stabilized with a despun 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.

[edit] DSCS III

DSCS III provides secure voice and data communications for the U.S. military. The program was also managed by DISA and the U.S. Air Force.

The spacecraft vehicle is 3-axis stabilization using reaction wheels, earth and sun sensors. Two articulated solar arrays produce 1240 watts and the space vehicle was supported with NiCd batteries. S-band and X-bands supported command and telemetry links. The propulsion subsystem was supported by a hydrazine as well.

The communications payload included six SHF channels with full Earth and narrow coverage capabilities. Receive antennas included two Earth coverage horns and one configurabe 61-beam nulling antenna. Transmit antennas included two Earth coverage horns, two configurable 19-beam antennas and one high gain parabolic gimballed dish.

[edit] DSCS III Service Life Enhancement Program (SLEP)

The DSCS SLEP provided performance enhancements for the last four DSCS III satellites. The enhancements were designed to increase the DSCS capacity by over 200 percent.