LGM-30A/B MINUTEMAN I
Perhaps the most successful American strategic weapon ever, Boeing's Minuteman continues to form the basis of the US land-based strategic deterrent force some forty years after the system's first test launch, and more than twenty years after the last example was built. Barring the unlikely development of an all-new US ICBM, Minuteman (in its ultimate LGM-30G model) looks likely to serve for at least another two decades, and several programs are underway to keep the system viable.
Minuteman originated in the same 1957 timeframe as Polaris, and originally the effort was aimed at using the new solid technology to produce a land-based weapon in the same general range class as the Navy missile. This rather quickly gave way to a plan for a solid-fuel ICBM; although to be larger than Polaris, it would be far smaller than Atlas or Titan. Although solid technology had its challenges, it also held out the promise of a much simpler missile that could be held for extended periods at virtually instant readiness, without the extensive, time-consuming, and dangerous fueling operations necessary with first-generation weapons. A small solid-fuel ICBM would also be far more economical to build and operate, permitting a larger force to be fielded.
Known early on as Weapons System Q and WS-133, the solid ICBM program later became known as Minuteman, with Boeing to serve as the overall head of the contractor team. The basic design was for a three-stage missile approximately forty feet long carrying a single W56 or W59 warhead in an Avco Mk.5 RV. The weapon (at least in one form) would be silo-based, and would be fired from underground. In order to gain experience with in-silo launching of solid motor vehicles, subscale models were tested at Edwards AFB, followed by full-size firings in 1959-1960; these latter tests used missiles with only enough first stage propellant to burn for several seconds, which was sufficient to clear the silo.
On February 1, 1961 the first real Minuteman launch took place, from a pad at Cape Canaveral. Unlike the initial Atlas and Titan shots, the first LGM-30 was a complete article, with a full guidance system and all stages "live". The launch was a success, and the missile was reported to have flown 4,600 miles. However, the second launch, on May 19, 1961 did not fare as well, being destroyed a minute and a half into the flight. The first try at a silo launch, again from Canaveral, ended dramatically on August 30, 1961 when all the stages fired simultaneously. A successful silo firing was conducted on November 17, 1961, with the missile traveling 3,000 miles.
With survivability a key driving force in the program, the Minuteman silos and launch control centers would each be separated by several miles. Each LCC would control ten silos, the facility itself being underground, with a connected area housing diesel generators, fuel, and sufficient consumables to keep the two-man crew going for several weeks, this being far longer than previous ICBM facilities could hope to remain functioning under wartime conditions.
Although stringent human reliability programs had long been a part of SAC, no chances were taken in the LCC design, the two crewmembers having to turn their launch keys (which were physically separated by a good distance) simultaneously, thus reducing the chance that one could overpower the other and launch missiles without orders. Also, two LCCs had to agree that a launch order was authentic before either could proceed. In later years, as the LCCs became more vulnerable to Soviet missiles, some silos were refitted to allow remote firing from SAC's EC-135 airborne command post aircraft. Aboveground at the LCC, ranch-style buildings were erected to house off-duty crews and support equipment. The silos themselves were not manned, being protected by fencing and sensors that would notify Sabotage Alert Teams of trouble.
Minuteman deployment would far outstrip that of all other American ICBMs combined, and this of course demanded a robust infrastructure. This would be centered at Ogden, Utah where the missiles were assembled. Unlike Atlas and Titan, which were moved with dry tanks, Minuteman had to be transported fully fueled, and as such had restrictions on the degree of shock, temperature, and humidity that could be withstood. Environmentally controlled transport containers would be used for the missiles; moving the vehicles and their missiles would be the job of a small number of C-133B Cargomasters, which could rapidly transit between Hill AFB and airfields near missile deployment sites. After the C-133Bs were phased out in the early 1970s, a few C-141 Starlifters were reworked for the Minuteman transport role. Upon reaching the destination silo by road, the container would be moved to the vertical, allowing the emplacement of the unarmed missile.
Reflecting the absolute security accorded nuclear weapons by the USAF, the job of moving the warheads by air went to the MAC (later AMC) Primary Nuclear Airlift Force. If serious defects were found in a deployed missile, the process was put into reverse to disarm the weapon and bring it back to Utah for repair. C-141s were also often used for moving warheads.
Given Minuteman's relatively diminutive size, basing options other than fixed silos were recognized from the start. A straightforward means of making the system mobile was to put missiles onto railcars; when dispersed over tens of thousands of miles of rail lines, a rail-mobile Minuteman force was seen as highly survivable in the face of a Soviet first strike. Using Hill AFB and other facilities as central operating locations, it was intended to keep trains, each with five Minuteman launch cars, crisscrossing railroads for several weeks at a time. Other mobile Minuteman concepts, including road mobile missiles, had been looked at, but putting the weapons on rails would combine survivability and a higher degree of accuracy, as rail-based operations would allow launchings from locations that were already well mapped-out. It was anticipated that several hundred rail-mobile missiles would enter service starting in 1964-65, and preliminary work on the launcher cars and other infrastructure was soon underway.
Despite the high priority that Rail Mobile Minuteman had enjoyed in 1959-60, the program was later canceled by President's Kennedy defense team. Factors that are said to have been behind the cancellation were the high costs and fielding the rail-based missiles, and projections that silo basing would remain survivable for the near future. This contention would soon lose favor among many planners as Soviet ICBMs became more numerous and powerful, and within a decade attention would once more be paid to making American ICBMs mobile.
The Kennedy Administration also set the total number of Minutemen to be deployed at one thousand. This was a marked decrease from the missile force planned by some within the USAF, and was part of the move towards a deterrent force built on the idea of Mutually Assured Destruction (MAD) rather than the previous goal of surpassing the Soviets. The 1,000-missile goal would be met within several years, and although the makeup of the force would be altered with the retirement of older models and the introduction of new variants, the overall number deployed would remain constant until Peacekeepers displaced some LGM-30s in the late 1980s.
The first of what would be hundreds of Minuteman launches from Vandenberg AFB took place on September 28, 1962. Aside from test flights, Vandenberg would also host operational training launches, with operational missiles and crews from the field coming to the base for firings down the Western Missile Range.
Although Minuteman I's operational date is officially given as December 1962, the first silos at Malmstrom AFB were actually brought on line by October 27 of that year, during the Cuban Missile Crisis. This was no doubt good news to strategic planners, who had even had to bring Atlas test missiles at Vandenberg up to operational readiness in an effort to get as much nuclear firepower on-line as possible.
Although a major leap forward in ICBM technology, the Minuteman Is (especially the "Wing 1" missiles) did have their shortcomings. The design range was not achieved with the Malmstrom missiles, as they had second stages made of steel rather than the lighter weight titanium units used on the later LGM-30B. This model also introduced the Mk.11 RV; although also made by Avco, this was markedly different from its Mk.5 predecessor, being of a flared conical shape. This configuration produced better accuracy, as the shape's trajectory was less affected by winds over the target area. Additionally, the radar cross section of such a design was probably reduced as well. Minuteman IB testing did suffer some setbacks; the first launch, on July 12, 1962 ended in failure when the missile blew up, and a following attempt on August 9 of that year suffered a similar fate.
Even with these early problems, the first Minuteman IBs were operational at Ellsworth AFB, South Dakota by July 1963. Despite their range shortfall, the Minuteman IAs were kept on in service until the last was replaced in January 1969. Ellsworth was the last base to use Minuteman I, finally phasing out the last of the old missiles out in 1975, their silos being filled by LGM-30Fs that had in turn been displaced by Minuteman IIIs at Minot.
