DSCS-3 Credit - USAF

DSCS satellites provided secure voice and data communications for the US military. The contract was managed by the DCA (Defense Communications Agency) for the USAF.

The spacecraft was 3-axis stabilized (0.1 deg control in pitch, roll) using reaction wheels, earth and sun sensors. Two articulated solar arrays produced 1240 W (BOL), powered a 28V bus, and recharged NiCd batteries of 105 AHr capacity. S-Band (SGLS) and X-Band command and telemetry links were provided. The blowdown hydrazine propulsion system used 16 x 1-lbf thrusters. The satellite had both full Earth and narrow coverage communications capabilities. Receive antennas included two Earth coverage horns and one steerable 61-beam nulling lens. Transmit antennas comprised two Earth coverage horns, two steerable 19-beam wave guide lens, and one high gain parabolic gimbaled dish. The payload included six SHF channels as follows:

• Ch1: 50 MHz, 40 W
• Ch2: 75 MHz, 40 W
• Ch3: 85 MHz, 10 W
• Ch4: 85 MHz, 10 W
• Ch5: 60 MHz, 10 W
• Ch6: 50 MHz, 10 W

General Electric the received contract in February 1977 for DSCS III. The first launch was in 1982. Recurring cost was quoted as $160 million in Aviation Week on 7 August 1995.

Design Life: 10 years. Typical orbit: Geosynchronous. Length: 2.10 m (6.80 ft). Maximum Diameter: 2.00 m (6.50 ft). Span: 11.50 m (37.70 ft). Mass: 2,613 kg (5,760 lb). Associated Launch Vehicle: Atlas II, Atlas IIA, Delta IV Medium, Shuttle, Titan 34D.

• 1982 October 30 - DSCS III-01 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Titan 34D. Perigee: 36,132 km (22,451 mi). Apogee: 36,171 km (22,475 mi). Inclination: 8.80 deg. Period: 1,454.80 min.

  Positioned in geosynchronous orbit at 105 deg W in 1982-1983; 135 deg W in 1983-1989; 130 deg W in 1989-1999. As of 2006 Sep 9 located at 94.39E drifting at 5.469W degrees per day.

• 1985 October 3 - USA 11 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Shuttle. Perigee: 35,434 km (22,017 mi). Apogee: 35,963 km (22,346 mi). Inclination: 0.30 deg. Period: 1,436.00 min.

  Released from STS 51J 10/4/85. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit; at 12 deg W in 1986; 42 deg W in 1995.

• 1985 October 3 - USA 12 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Shuttle. Perigee: 35,633 km (22,141 mi). Apogee: 35,963 km (22,346 mi). Inclination: 0.30 deg. Period: 1,436.00 min.

  Released from STS 51J 4 October 1985; boosted into orbit with DSCS 3 F3 on single IUS booster. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit; at 180 deg E in 1994.

• 1989 September 4 - USA 44 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Titan 34D. Perigee: 35,771 km (22,227 mi). Apogee: 35,808 km (22,250 mi). Inclination: 5.00 deg. Period: 1,436.30 min.

  Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit; at 60 deg E in 1995.

• 1989 September 4 - USA 43 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Titan 34D. Perigee: 35,777 km (22,230 mi). Apogee: 35,799 km (22,244 mi). Inclination: 6.10 deg. Period: 1,436.10 min.

  Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit; at 57 deg E in 1995.

• 1992 February 11 - USA 78 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas II. Perigee: 30,675 km (19,060 mi). Apogee: 35,503 km (22,060 mi). Inclination: 0.90 deg. Period: 1,300.50 min.

  Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option. Positioned in geosynchronous orbit; at 135 deg W in 1995.

• 1992 July 2 - USA 82 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas II. Perigee: 35,775 km (22,229 mi). Apogee: 35,800 km (22,200 mi). Inclination: 0.20 deg. Period: 1,436.20 min.

  Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option. Positioned in geosynchronous orbit at 12 deg W in 1995-1996. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

• 1993 July 19 - USA 93 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas II. Mass: 2,615 kg (5,765 lb). Perigee: 183 km (113 mi). Apogee: 35,764 km (22,222 mi). Inclination: 26.10 deg. Period: 625.80 min.

  Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option. Positioned in geosynchronous orbit at 175 deg E in 1995-1997.

• 1993 November 28 - USA 97 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas II. Mass: 2,615 kg (5,765 lb). Perigee: 195 km (121 mi). Apogee: 35,501 km (22,059 mi). Inclination: 26.40 deg. Period: 625.40 min.

  Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option. Positioned in geosynchronous orbit at 52 deg W in 1995; 60 deg E in 1997. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

• 1995 July 31 - USA 113 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas IIA. Mass: 2,610 kg (5,750 lb). Perigee: 35,787 km (22,236 mi). Apogee: 35,787 km (22,236 mi). Inclination: 0.00 deg.

  Positioned in geosynchronous orbit; located at 53 deg W in 1997.

• 1997 October 25 - USA 135 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas IIA. Perigee: 35,770 km (22,220 mi). Apogee: 35,800 km (22,200 mi). Inclination: 0.00 deg.

  Geosynchronous. Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option.

• 2000 January 21 - USA 148 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas IIA. Mass: 1,232 kg (2,716 lb). Perigee: 35,780 km (22,230 mi). Apogee: 35,790 km (22,230 mi). Inclination: 0.00 deg.

  Part of the US Air Force Defense Satellite Communications System. To be stationed in geosynchronous orbit over the Pacific Ocean.

• 2000 October 20 - USA 153 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Atlas IIA. Mass: 1,235 kg (2,722 lb). Perigee: 35,780 km (22,230 mi). Apogee: 35,790 km (22,230 mi). Inclination: 0.00 deg.

  Military Communications satellite. Launch delayed from October 12 by spacecraft problem. The US Air Force Defense Satellite Communications System satellite was placed by the Centaur upper stage into a 148 km x 898 km x 29.3 deg parking orbit. A second burn put it into a 218 km x 35,232 km x 26.0 deg transfer orbit. The DSCS III B-11 IABS-8 apogee stage, with two Primex R4D liquid apogee engines, circularised the orbit at geostationary altitude on October 21 and then separated from the DSCS.

• 2003 August 29 - USA 170 - Launch Site: Cape Canaveral. Launch Vehicle: Delta IV Medium. Mass: 1,235 kg (2,722 lb).

  Delayed from July 1, 11 and 23, then August 3 and 28.

• 2003 March 11 - USA 167 - Program: DSCS. Launch Site: Cape Canaveral. Launch Vehicle: Delta IV Medium. Mass: 1,235 kg (2,722 lb).

  First flight of a fully cryogenic orbital launch vehicle. Delayed from December 2001, February 2, 6, 8, 11, 12 and March 8 2003. Satellite mas 2,733 kg with kick stage.

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