The problem of active control of the transient dynamic response of large space structures, modeled as equivalent continua, is investigated here. The effects of initial stresses, in the form of inplane stress resultants in an equivalent plate model, on the controllability of transverse dynamic response, are studied. A singular solution approach is used to derive a fully coupled set of nodal equations of motion which also include nonproportional passive damping. One approach considers a direct attack on this system of nodal equations. An alternative scheme implements a reduced-order model of coupled ordinary differential equations which are obtained in terms of the amplitudes of the pseudomodes of the nominally undamped system. Optimal control techniques are employed to develop a feedback control law. Algorithms for the efficient solution of the Riccati equation are implemented. Several examples are presented which involve the suppression of vibration of the transient dynamic response of the structure using an arbitrary number of control force actuators.