Simulation of spacecraft motion in separation test

This paper presents a mathematical model of the spacecraft motion during the separation test on a low frequency suspension system that is designed and fabricated in order to simulate the free fall condition of the spacecraft as it occurs in space during the spacecraft separation from the launch vehicle. The suspension system consisted of elastic bungee cords to hold the spacecraft in course of the separation process during the test. The model, developed here to predict the parameters of the rigid-body separation dynamics, incorporates the effect of ejection springs and nonlinear behavior of the bungee cords. The Lagrange method was used to drive the equations of motion and was solved using forth order Runge-Kutta method. Separation tests were carried on structural model of spacecraft by releasing the clamp-band. The displacement of the spacecraft was measured by a high accuracy Laser Tracker. The predicted response of the spacecraft matches closely with the test data.