Initial Defense Communications Satellite Program

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Main article: Defense Satellite Communications System

Initial Defense Communications Satellite Program
Satellite Communications
Specifications
Spacecraft typeSmall satellite
Launch mass45 kilograms (99 lb)
Equipment
RegimeSubsynchronous
Design life6 years
Production
StatusRetired
Launched35 (8 launch failures, 27 in orbit)
Maiden launch16 June 1966
Last launch13 June 1968

The Initial Defense Communications Satellite Program or IDCSP was the first United States Department of Defense communications satellite constellation and the first stage of the Defense Communications Satellite Program (DCSP). Launched in five groups by Titan IIIC launch vehicles to near equatorial, subsynchronous orbits between 1966 and 1968, they were intended to be experimental testbeds. They were so successful that, by the time of the launch of the last set of eight satellites, the IDCSP was deemed operational and renamed Initial Defense Satellite Communications System or IDSCS. This system allowed real-time collection of battlefield intelligence during the Vietnam War. A total of 35 IDCSP satellites were launched, 27 successfully.

Background

The Initial Defense Communications Satellite Program or IDCSP was the first stage in the

Atlas Agena rockets for a total cost of $165 million ($60 million of which would be spent on satellites).[2]

Earth station if one failed.[5] Full coverage would be provided by at least 12 satellites.[2]

Thus, the Titan IIIC was chosen to replace the Atlas Agena as the IDCSP launch vehicle. This change did not go unchallenged; the

House Committee on Government Operations denounced the move, saying that the "plan for short-range economies depending on a high-risk program may prove costly in the end". With the selection of the Titan IIIC as the IDCSP booster, the Pentagon dropped contract negotiations with Philco, preferring to develop the satellites in-house.[2] Through early 1965 the satellites were still being designed so that they could be lofted to Medium Earth Orbit via Atlas Agena in the event that the Titan IIIC was not available.[3]

The Titan IIIC was developed in time for use, the first launch taking place just four months behind the original schedule. The satellites built by 1966, sufficient for three launches, had cost just $33 million to produce (an overage of $3 million on original estimates).[2]

Design

Initial Defense Communications Satellite Program satellite diagram

Developed primarily by

communications satellites, spin-stabilized, 26-sided polygons, 86 cm (34 in) in diameter, covered with solar panels, and had a mass of 45 kilograms (99 lb).[5] They were specifically designed to be simple to avoid the problems faced by the earlier Courier and Advent programs:[6] no in-orbit control mechanisms were included, nor were the satellites equipped with batteries. The satellites were equipped with an automatic radiation shut-off device to deactivate them after six years in orbit.[1]

Each satellite contained a single 3.5

Spread Spectrum Multiple Access (SSMA) modulation techniques.[8] The Eimac Division of Varian Associates supplied one of the two traveling wave amplifiers used by the satellite's transmitter, the other being produced by Watkins-Johnson Company.[2] Because of the low power of the satellites' transponders, as well as its low-gain antenna, the receiving installations had to be very large.[7]

Operational history

Artist's rendering of a Transtage deploying IDCSP satellites
Artist's rendering of a Transtage deploying IDCSP satellites

The first launch of IDCSP satellites took place at 14:00:01 GMT on 16 June 1966 from Cape Canaveral Space Launch Complex 41 aboard the fourth Titan IIIC. After a successful Transtage burn placed the last stage of the Titan into a 33,670 km (20,920 mi) by 33,892 km (21,060 mi) orbit, the first seven IDCSP satellites (along with the Gravity Gradient Technology Satellite, a stabilization test satellite built on the same satellite bus) were dispersed one-by-one into orbit, each drifting 27.8° per day. Communications were conducted successfully between Fort Dix, New Jersey, and sites in California, England and Germany.[4]

The second set of IDCSP satellites, totaling eight, was lost 26 August 1966 when a faulty payload fairing caused the launch failure of the fifth Titan IIIC.[4] This proved to be the last unsuccessful Titan IIIC launch.[4]

On 18 January 1967, the seventh Titan IIIC launch successfully placed a full constellation of eight IDCSP satellites into orbit,

North Atlantic Treaty Organization states, which referred to the program as NATO-1.[9]

In all, 35 IDCSP satellites were launched in 5 groups by Titan IIIC launch vehicles, 27 successfully[10] to near equatorial, subsynchronous orbits. The automatic shut-off device installed on the IDCSP satellites did not work reliably, and many satellites operated long past their six-year lifespan. As of 1975, six were still functioning.[1]

Technical and systems management assistance was provided to the USAF's

geosynchronous satellites.[5]

Launches

Titan IIIC-11 launch 16 June 1966
Titan IIIC-13 launch 18 January 1967
AN/TSC-54 communications ground terminal
Initial Defense Communications Satellite Program[10]
Launch Name(s) Launch date Rocket Mass (kg) Orbit regime IRON Re-entry
First
IDCSP 1 16 June 1966 Titan IIIC 45 MEO 9311 In orbit
IDCSP 2 16 June 1966 Titan IIIC 45 MEO 9312 In orbit
IDCSP 3 16 June 1966 Titan IIIC 45 MEO 9313 In orbit
IDCSP 4 16 June 1966 Titan IIIC 45 MEO 9314 In orbit
IDCSP 5 16 June 1966 Titan IIIC 45 MEO 9315 In orbit
IDCSP 6 16 June 1966 Titan IIIC 45 MEO 9316 In orbit
IDCSP 7 16 June 1966 Titan IIIC 45 MEO 9317 In orbit
Second
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
IDCSP 26 August 1966 Titan IIIC 45 MEO Launch failure
Third
IDCSP 8 18 January 1967 Titan IIIC 45 MEO 9321 In orbit
IDCSP 9 18 January 1967 Titan IIIC 45 MEO 9322 In orbit
IDCSP 10 18 January 1967 Titan IIIC 45 MEO 9323 In orbit
IDCSP 11 18 January 1967 Titan IIIC 45 MEO 9324 In orbit
IDCSP 12 18 January 1967 Titan IIIC 45 MEO 9325 In orbit
IDCSP 13 18 January 1967 Titan IIIC 45 MEO 9326 In orbit
IDCSP 14 18 January 1967 Titan IIIC 45 MEO 9327 In orbit
IDCSP 15 18 January 1967 Titan IIIC 45 MEO 9328 In orbit
Fourth
IDCSP 16 1 July 1967 Titan IIIC 45 MEO 9331 In orbit
IDCSP 17 1 July 1967 Titan IIIC 45 MEO 9332 In orbit
IDCSP 18 1 July 1967 Titan IIIC 45 MEO 9333 In orbit
IDCSP 19/DATS 1 July 1967 Titan IIIC 45 MEO 9334 In orbit
Fifth
IDCSP 20 13 June 1968 Titan IIIC 45 MEO 9341 In orbit
IDCSP 21 13 June 1968 Titan IIIC 45 MEO 9342 In orbit
IDCSP 22 13 June 1968 Titan IIIC 45 MEO 9343 In orbit
IDCSP 23 13 June 1968 Titan IIIC 45 MEO 9344 In orbit
IDCSP 24 13 June 1968 Titan IIIC 45 MEO 9345 In orbit
IDCSP 25 13 June 1968 Titan IIIC 45 MEO 9346 In orbit
IDCSP 26 13 June 1968 Titan IIIC 45 MEO 9347 In orbit
IDCSP 27 13 June 1968 Titan IIIC 45 MEO 9348 In orbit

References

  1. ^
    OCLC 1042380582
    .
  2. ^ a b c d e f g ""DOD Communications Satellite Set". Aviation Week and Space Technology. McGraw Hill Publishing Company. 27 June 1966. pp. 25–26. Retrieved 25 May 2021.
  3. ^ a b c ""DOD Communications Satellite Set". Aviation Week and Space Technology. McGraw Hill Publishing Company. 9 May 1966. p. 33. Retrieved 27 April 2021.
  4. ^ a b c d e f Andrew LePage (18 June 2015). "The First Missions of the Titan IIIC". Drew Ex Machina. Retrieved 28 April 2021.
  5. ^ a b c "IDCSP 1-1". NASA. Retrieved 27 April 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  6. ^
    Bibcode:1997bify.book.....B
    . SP-4217.
  7. ^ a b Robert Cook (March 1994). "DSCS - Past, Present, and Future" (PDF). Alexandria, Virginia: Defense Technical Information Center. Archived (PDF) from the original on May 14, 2021.
  8. ^ "IDCSP 3-1". NASA. Retrieved 27 April 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  9. ^ a b Krebs, Gunter. "IDCSP → DSCS-1 (NATO 1)". Gunter's Space Page. Retrieved 12 May 2021.
  10. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved 27 April 2021.
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