Tarbiat Modarres


In this paper, a closedloop strategy in the vertical plane is derived in order to determine the thrust direction of a launch vehicle in terms of velocitiestobe gained The two velocities-to-be-gained are utilized, here, for a given altitude and zero vertical speed in a specied nal time The formulation is obtained for constant gravity assumption, but it works when the velocitiesto-be-gained are obtained for a spherical-Earth model via explicit or implicit relations-