The Trajectory Correction Kit (TCK) is a completely self-contained retrofit kit that is externally and fixedly mounted as an add-on to the rear (aft of the tailfins) of an existing, unguided rocket. The TCK continuously measures the pitch and yaw of the rocket as it is released from the launch tube and during the initial seconds of the flight and calculates the trajectory correction that is necessary to eliminate the measured pitch and yaw. Then it activates selected thrusters among the thrusters that are positioned around the circumference of the rocket body so as to steer the rocket in a direction until the measured pitch and yaw are eliminated. This results in significant reductions in both the rocket flight path dispersion and collateral damage.