Abstract: This article studies the six-degree-of-freedom trajectory simulation of small multiple stage solid launch vehicles with control systems using lateral jet thrusters and grid fins. It provides the installation model, thrust model and the control law for the starting-up and cutoff operations of the lateral jet thrusters, and deals with the calculation method of aerodynamics and aerodynamic moment. Furthermore, it builds a thrust model of the solid rocket motor, and presents the whole six-degree-of-freedom kinetic equations and motion equations. Simulation results show that the six-degree-of-freedom trajectory simulation model thus established can express the flight performance of the launch vehicle with accuracy. The solid launch vehicle researched can meet the launching capability requirements for launching a payload of 300 kg to 200 km Sun-synchronous orbit, and the attitude control system can ensure the attitude control precision of the launch vehicle. All this can help provide a theoretic basis for the scheme demonstration and preliminary design of the solid launch vehicle.

Key words: small solid launch vehicle, trajectories, jet, grid fin, launching capability