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Aviation History
1963
1963 - 2005.PDF
Loading an XLGM-30A Minuteman into an operational training and test silo at Vandenberg AFB, California, for a US Air Force routine training shot earlier this year. When the silo lid has been moved aside, the trans porter/erector will be elevated to the vertical position and the missile lowered in the manner depicted on page 806 At the moment only the first course, a review of calculus, is offered; but this will expand into what the Air Force calls "inte grated sequences of courses in advanced mathematics, the physics of space environment and the engineering sciences." Civilian and Air Force instructors will teach the engineering curriculum. Naturally there is a price to pay for this pampering, and it adds up to three years of missile-station duty plus a guarantee of two more years in the Air Force. Even so, this is a cheap way to keep men in the service, away from the lure of higher-paid civilian jobs in the vast space/defence industry. The launch-control capsule exists as something other than a study cubicle for bright-eyed young "men who have passed psy chology tests. One of the most important considerations in the waiting game is to ensure that no trigger-happy enthusiast can launch a theromonuclear war of his own making. As stated earlier, a Minuteman launch-control oversees ten missiles. Before any missile can be fired, co-ordinated command action must be made by two launch-control centres. Even then, both officers in both launch-control centres must follow established procedures. In addition, any firing signal originating in a single capsule appears in all the 14 others in the wing. An INHIBIT signal from any launch- control centre will give a five-minute launch delay, which is con sidered time enough to check the status. As with any weapon system in SAC, original coded commands Ml Minuteman ICBMs are delivered [by air, either to the Atlantic or Pacific missile ranges or to the airfield at the heart of an operational complex. In this picture a loaded SSCBM (shipping and storage con tainer, ballistic missile, protecting the "bird" against extremes of shock, vibration, temperature and humidity) is being withdrawn from a Douglas C-I33B Cargomaster at Malmstrom AFB FLIGHT International, 14 November 1963 809 must come from the President himself before any launch action can be taken at headquarters and relayed to the missile sites. A mechanical defect in the missile automatically precludes launch. With literally hundreds of Minutemen littering the country, nothing but the most elaborate safety interlocks are acceptable. The time element is especially vital, because these missiles are capable of leaving their holes after a total countdown of only 32sec. Launch can be stopped at up to T-26sec; after that, no other course but fire is possible. Firing can be a salvo of 50 at once or a selected ripple, depending on the SAC war plan. While it is possible for one launch-control centre to launch its ten birds all at once, there would be, as a launch officer put it, "a hell of a long wait because of inhibiting procedures" before it could launch all the 50 in the squadron. The Missile Silo Structurally, the Minuteman emplacement is a simple affair. Each silo, including its share of the launch-control centre but excluding equipment, costs $4.5m. A single steel liner tube on a concrete footing encloses the missile sitting on a shock-absorbing mounting ring. The missile can turn on its mount in azimuth for guidance positioning. Access to a shock-mounted instrument floor, ringing the missile tube about 20ft below the surface, is made via a removable aluminium ladder. About 8ft below the instrument floor a shock-mounted utility-power floor also rings the missile tube. A series of batteries for emergency power is located on this level, together with environmental-control equipment. Access to the warhead and guidance section is achieved through a large port cut in the silo tube. It is at this point that the guidance mirror-alignment system "looks" from the silo into the missile. Most of the electronic equipment, in racks on the upper floor, is made up of power supplies and computer decoders for launch sequencing commanded by the launch-control centre. Once any of the access doors to the equipment classified "secret" are opened, the codes are automatically dissipated and outside power shut off. Changing the target for a particular missile is a fairly elaborate procedure, which entails going down into the normally unmanned silo and changing a series of cams in the decoders. While this operation takes about 3hr to accomplish, the new information is absorbed by the coding computing system in lOsec. Thereafter the Minuteman knows its new destination exactly. Capping the completely hardened silo is a 4ft-thick reinforced- concrete sliding door, that zipps back 12 to 15sec before launch. From that moment on, the missile is exposed to the elements and its cocoon-like existence is over. Previously, year in and year out, the missile has enjoyed a comfort environment, with precisely controlled air temperature and humidity produced in the missile support building buried underground but not fully hardened about 50ft from the silo tube. In this cell, a standby diesel generator drives an alternator to provide missile power in the event of outside power failure. Normally the missile and all its equipment draws current from standard commercial power lines running to the silos. In the unlikely event of failure of both this supply and the diesel standby, there is still sufficient battery power in the silo to last for 50hr. A small air compressor is installed at each silo, kept busy pressur izing its share of the miles of buried cable at from 6 to 9 lb/sq in, to exclude moisture and aid in finding breaks in the line. Loading a bird into the silo hole takes about a day, using a special transporter/erector some 64ft long, described as "the biggest vehicle on US highways." Encased missiles, less warhead, are flown into the base inside C-133 Cargomaster aircraft, and then trans ferred to the road masters. Once at the site, the erector pivots to the vertical and a winch inside the air-conditioned transporter box lowers the missile carefully down into the hole. At this point in time, no one can say with certainty just how long a Minuteman will stay emplaced. The complete guidance package can be changed while the missile remains down its hole, but any work on the stage nozzle systems (for example) means pulling the complete bird. Hopes are high for "several years"; no one is fool enough to guarantee a specific number, although three years has been suggested as a target. This is not to say that high mean time between failure is not a specification requirement for every item of equipment throughout the 133A weapon system. Right at this moment Minuteman gyros are humming and Minuteman officers are sitting in launch-control facilities. To morrow and the next day, and so on for many months, more and more Minutemen will be lowered into their deep holes. Perhaps this is the way to maintain peace.
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