Design of a Pulsed Solid Propellant Divert and Attitude Control System (DACS)

The End game for a kill vehicle of Hit-to-Kill Missile is very critical, as it depends on its variable divert and attitude correction capabilities. A Solid DACS provides quick reaction propulsion that positions the vehicle to intercept its target. The Pulsed Solid DACS provides propulsion for control error correction and for vehicle maneuvering. The attitude control systems (ACS) have six thrusters to provide roll, pitch and yaw control. These thrusters act synergistically and precisely aim the vehicle seeker to properly view the target. The four divert thrusters provide short/ long pulses to quickly and accurately position the kill vehicle for a collision with target. A high burn rate propellant is used to meet the divert and attitude control thrust requirement. Four divert thrusters have the variable throat areas for the quick divert of the kill vehicle. The nozzle throat areas are throttled such that the mass flow is met for the required thrust for each thruster. Pintle valves are used for the throat area throttling purpose. The attitude control thrusters have the fixed throat area which will be used for the attitude control capability of kill vehicle. A pulsed motor has been designed to operate for divert thrust and attitude control for first few seconds and second motor (second pulse) will operate with a time delay after first motor operation. This is achieved by configuring an annular motor around the first rocket motor (which get emptied during the first pulse) and separated by two pulse separation diaphragms (PSD). The propellant gases flow into the first pulse motor and actuated by the first pulse rocket motor nozzles to produce variable divert and fixed attitude control thrust for second pulse duration.