387. Weighing the Atlas Silo Crib

Paper

Abstract

This paper was presented at the Twenty-second Annual National Conference of the Society of Aeronautical Weight Engineers at St. Louis, Missouri, April 29-May 1, 1963. One means of storing the Air Force Atlas ICBM missile in a state of readiness is the underground unitary silo. Inside the silo, entirely suspended by shock absorbing springs, is an eight-sided steel crib structure containing all the elements necessary to launch and Atlas missile. A 50-foot tunnel connects the silo to a two-level launch control center, also underground and shock isolated.
The crib suspension-system springs were stiffness calibrated by the supplier so that the crib’s elastic center could be calculated. However, the calculated weight and the center of gravity were not known to the accuracy desired. For maximum effectiveness, the elastic center of the suspension system must coincide with the crib’s center of gravity. This reduces the spurious crib perturbations and, with the action of damping units, tends to keep the oscillations vertical harmonic motions. The weighing and center of gravity determination program was undertaken to satisfy these requirements.