(U) Defense Satellite Communications System (DSCS) II

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)

Overview: (U)
(U) DSCS II satellites represented an upgrade of the capabilities of the early DSCS satellites which were the Phase I space segment of DSCS.  The DSCS II systems emphasized hardening, anti-jamming protection, and an increase in channel capability over the original DSCS satellites.  A full compliment of four DSCS II satellites was achieved on 14 December 1978.  The final DSCS II satellite is muted and is being maintained as an inactive spare.

Description: (U)
(U) The first DSCS II satellite was launched in Nov 1971.  The DSCS II satellites were launched in pairs.  Each DSCS II satellite has four antennas.  Two 18-degree earth coverage horns and two steerable dish antennas.  They are all mounted on the inner shell of the satellite platform which is despun to ensure the antennas always point towards the Earth.  The outer shell is spun to provide stability.  The two steerable dish antennas provide spot beam coverage and both can receive and transmit simultaneously. One dish antenna provides area spot beam coverage using a 6-degree beamwidth.  The other antenna provides narrower spot beam coverage with a 3-degree beamwidth.  The four channels provide the flexibility to handle a wide variety of links and to interface with many different sizes of terminals.  All the communication subsystem assemblies are redundant.  

(U) The last DSCS II satellite was launched in 1989 onboard a Titan 34D with the DSCS III satellite F4.  DSCS II satellite have been replaced by nine DSCS III satellites in orbit including five primary and four reserve satellites. The final DSCS II satellite is muted and is being maintained as an inactive space.  The DSCS Service Life Enhancement Program (DSCS SLEP) provides performance enhancements for the last four DSCS III satellites. These enhancements are designed to increase the DSCS tactical system capacity by over 200 percent. 

User Impact: (U)
(U) To be supplied.

Programmatics: (U)
(U) Operational.
	(U) Termination: 12/1996 (1QFY1997).

Related Initiatives: (U)
(U) Adv Wideband Satellite (AWS), AN/WSC-6(V)X, DISA STEP, DSCS III, Eastern Range, Lightwt Multi-band Sat Terminal, MIDAS, STAR-T

Related Requirements: (U)
(U) None.

Related Categories: (U)
(U) Satellite Operations, SHF Satellite Systems, Spacelift

Road Map Placements: (U)
(U) MILSATCOM, National Security Space Road Map.

Lead Office: (U)
(U) Air Force.

Date of Information: (U)
01 February 1997

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)