D-1A equipment module structure test
The Centaur Equipment Module (E/M) structural test program was performed in two parts due to an unscheduled hardware failure in the first test series. The objectives of the initial test program were to define the flexibility characteristics of the E/M, verify the design load capability, and determine its ultimate strength capability by loading to structural failure. However, during the first failure test attempt, the Intelsat IV MPA failed instead of the E/M. Therefore a new adapter was fabricated to simulate the HEAO mission adapter and the second series of tests were then performed. They concluded with the failure of the E/M forward interface ring resulting in about 3.5 degrees of permanent set on the high compression side. Nevertheless, the linear or useable strength capability of the E/M is greater or equal to that which is required for the HEAO missions. The E/M is deemed structurally qualified for the HEAO missions.