A mid-course, trajectory-match intercept of intercontinental ballistic missiles is analyzed. The intercept is accomplished by using a multistage rocket to boost an interceptor vehicle onto a ballistic trajectory in the same direction of flight as the warhead trajectory, so that the two trajectories are almost tangent at a selected intercept point. Near the intercept point, a final rocket is ignited to accelerate the vehicle and match the warheads position and velocity. A simplified analysis is performed for the case of a co-planar intercept over a spherical, nonrotating earth. Intercept trajectories are determined from the trajectory geometry and the rocket equations of motion. An approximate method is derived to estimate the thrusts and rocket weights required to boost an interceptor vehicle onto these trajectories.