1722. Predicting Tilt of a Double Pendulum

Paper

Abstract

During assembly of the Hubble Space Telescope at Lockheed, the various sections are required to hang very close to level when hoisted. The hoisting gear is a delta (triangular) frame suspended by three chains from a single hook on the hoist. Three long cables attached to the lower side of the delta frame drop down to attach to the Space Telescope. The cables and the telescope act as a pendulum hanging from the delta frame. But the delta frame hanging from the hook is also a pendulum, hence our description of this arrangement as a double pendulum. The three chains and three cables all have turnbuckles. This paper describes the method used to calculate the proper setting of the lengths of the turnbuckles.