Trident I C-4 Background
Lockheed commenced a TRIDENT I (C4) Advanced Development Program on 15 November 1971, which was the start date for contract N00030-72-C-0108.The IOC of the C4 was established as CY 1979. The SECDEF on 23 December 1971 approved Navy Program Budget Decision #317 to increase ULMS budget funding to permit acceleration of the program calling for deployment of a new class of SSBNs capable of carrying the 4000 nm TRIDENT I missile and, later, the 6000 nm TRIDENT II missile. On 1 November 1973, Lockheed commenced the TRIDENT I (C4) Missile contract for missile system development plus the production of the first missiles including reentry vehicle shells. The contract provided for support equipment and technical services to outfit and support operation of TRIDENT I and backfit submarines, SWFPAC, POMFLANT, and training facilities.
The major engineering challenges of the TRIDENT missile development, which required innovation as well as state-of-the-art advances, derived from the goals of doubling the missile range in the same volume and weight while keeping the already surprisingly good accuracy at this doubled range. Improving the accuracy involved navigation and fire control improvements as well as missile and guidance. In addition to these technological challenges, there were equally important design constraints derived from cost and reliability goals. Development costs were constrained in a period when inflation was high, and different in the various segments of the economy, while inventories were generally very low and lead times long. Production cost was an additional major design consideration and reliability (hence operational dependability) was, as always, given top priority.
The accuracy of the new missile system, to maintain effectiveness, was to be equivalent at 4000 nm to that of the POSEIDON C-3 at 2000 nm. To gain the increased full payload range, it was necessary to give up some of the maximum possible ABM exchange ratio which would only be of value should the then proposed ABM Treaty be abrogated. As a hedge against such a contingency, advanced development of a maneuvering, evader reentry vehicle capable of being carried by the missile was included in the program.This provided reasonable assurance that a possible later decision to initiate engineering development of such a system in response to Soviet ABM deployment would not require reengineering of the weapon system. Six flight tests from 6 March 1974 to 13 November 1975 developed the new reentry vehicle (Mk 4) for C4, along with a Mk 500 maneuvering reentry vehicle, demonstrating the feasibility of the concept and its compatibility with the TRIDENT missile system.
The C4 missile development flight test program commenced on 18 January 1977 with the successful launching of C4X-1 from the flat pad (25C) at Cape Kennedy. This was followed by 17 additional C4X launches from pad 25C. Of these 18 flights, 15 were successful, 1 was a partial success, 1 was a failure and1 was a no test (due to ground support equipment error). The C4X program completed on 23 January 1979. This was followed by the firing of 7 PEMs (Performance Evaluation Missiles versus Production Evaluation Missiles) from the SSBN-657 during the period 10 April 1979 through 31 July 1979. PEM-1had a first stage motor failure but PEMs 2 through 7 were successful. It was this successful flight test program that lead to SECNAV James Woolsey to comment in January 1980 that TRIDENT I (C4) was "the most successful submarine launched ballistic missile development program to date."
Moreover, the development flight test program was progressing so satisfactorily that after the 12th flight test of the C4X was successfully conducted, Lockheed on 19 May 1978 proposed that the total number of development (C4Xs and PEMs) be reduced from 30 to 25. Following the 16th flight test which was successful, the Director of SSPO determined on 27 November 1978 that the technical objectives of the C4 development program had been met and that the development flights could be reduced from 30 to 25 flight tests (18 C4Xs and 7 PEMs).
Although the flight test program was progressing satisfactorily, there were problems on the ground. During static ground firings of rockets motors, there were two internally-induced detonations which resulted in a major effort to resolve and modify the propellant. During another static ground firing, exercising of the flight termination system resulted in an externally-induced detonation. This resulted in a modification to the flight termination system.
Finally on 20 October 1979, the USS Francis Scott Key (SSBN-657), a POSEIDON submarine "backfitted" with TRIDENT I (C4) missiles, deployed for deterrent patrol from Charleston, South Carolina, carrying 16 tactical (4000 nm) TRIDENT I (C4) missiles.
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