Directory of U.S. Military Rockets and Missiles
Appendix 3: Space Vehicles
Copyright © 2003 Jos Heyman
(HTML formatting by Andreas Parsch)


The second generation of operational communications satellites for the US military services, was named Defense Satellite Communications System (DSCS) II. Designated ES-4A, the satellites provided communication services from geostationary orbits. The 521 kg satellites were built by TRW, were fitted with two transponders operating in the 7/8 GHz band although later satellites carried six transponders. The satellites were launched in pairs and the operational constellation consisted of four satellites placed at 60°E, 175°E, 12°W and 135°W, as well as two in-orbit back-ups.

Image: Author's collection
DSCS II-1 (1971-095A)

Name Intl. Designation Launch Re-entry Notes
DSCS II-11971-095A3-Nov-1971 Also known as Ops-9431
DSCS II-21971-095B3-Nov-1971 Also known as Ops-9432
DSCS II-31973-100A13-Dec-1973 Also known as Ops-9433
DSCS II-41973-100B13-Dec-1973 Also known as Ops-9434
DSCS II-51975-040A20-May-197526-May-1975 Also known as Ops-9435; failed to achieve correct orbit
DSCS II-61975-040B20-May-197526-May-1975 Also known as Ops-9436; failed to achieve correct orbit
DSCS II-71977-034A12-May-1977 Also known as Ops-9437
DSCS II-81977-034B12-May-1977 Also known as Ops-9438
DSCS II-9---25-Mar-1978--- Also known as Ops-9439; failed to orbit
DSCS II-10---25-Mar-1978--- Also known as Ops-9440; failed to orbit
DSCS II-111978-113A14-Dec-1978 Also known as Ops-9441
DSCS II-121978-113B14-Dec-1978 Also known as Ops-9442
DSCS II-131979-098A21-Nov-1979 Also known as Ops-9443
DSCS II-141979-098B21-Nov-1979 Also known as Ops-9444
DSCS II-151982-106A30-Oct-1982  
DSCS II-161989-069A4-Sep-1989 Also known as USA-43

Launch dates of the DSCS II series

The next generation of DSCS satellites has been designated as ES-5A.

Background History


The first operational military communications satellite system was the Initial Defense Satellite Communications System (IDSCS) which commenced as a research and development project but was converted into a global operational network for high volume communications in 1968. It was initially known as the Initial Defense Communications Satellite Program (IDCSP).

The system consisted of a string of satellites which were in an orbit which was 90 minutes short of a geostationary orbit, drifting each day from west to east by 27.8° at altitudes of approximately 33,800 km. Built by Philco, each satellite, which had a mass of 45 kg, carried a single transponder operating at 7/8 Mhz.

Photo: Author's collection
IDSCS-1 (1966-053B)

Name Intl. Designation Launch Re-entry Notes
IDSCS-11966-053B16-Jun-1966 Also known as Ops-9311
IDSCS-21966-053C16-Jun-1966 Also known as Ops-9312
IDSCS-31966-053D16-Jun-1966 Also known as Ops-9313
IDSCS-41966-053E16-Jun-1966 Also known as Ops-9314
IDSCS-51966-053F16-Jun-1966 Also known as Ops-9315
IDSCS-61966-053G16-Jun-1966 Also known as Ops-9316
IDSCS-71966-053H16-Jun-1966 Also known as Ops-9317
IDSCS---26-Aug-1966--- Eight satellites failed to orbit
IDSCS-81967-003A18-Jan-1967 Also known as Ops-9321
IDSCS-91967-003B18-Jan-1967 Also known as Ops-9322
IDSCS-101967-003C18-Jan-1967 Also known as Ops-9323
IDSCS-111967-003D18-Jan-1967 Also known as Ops-9324
IDSCS-121967-003E18-Jan-1967 Also known as Ops-9325
IDSCS-131967-003F18-Jan-1967 Also known as Ops-9326
IDSCS-141967-003G18-Jan-1967 Also known as Ops-9327
IDSCS-151967-003H18-Jan-1967 Also known as Ops-9328
IDSCS-161967-066A1-Jul-1967 Also known as Ops-9331
IDSCS-171967-066B1-Jul-1967 Also known as Ops-9332
IDSCS-181967-066C1-Jul-1967 Also known as Ops-9333
IDSCS-191968-050A13-Jun-1968 Also known as Ops-9341
IDSCS-201968-050B13-Jun-1968 Also known as Ops-9342
IDSCS-211968-050C13-Jun-1968 Also known as Ops-9343
IDSCS-221968-050D13-Jun-1968 Also known as Ops-9344
IDSCS-231968-050E13-Jun-1968 Also known as Ops-9345
IDSCS-241968-050F13-Jun-1968 Also known as Ops-9346
IDSCS-251968-050G13-Jun-1968 Also known as Ops-9347
IDSCS-261968-050H13-Jun-1968 Also known as Ops-9348

Launch dates of the IDSCS series

Back to Directory of U.S. Military Rockets and Missiles, Appendix 3

Last Updated: 22 February 2003