 The PAC-3 missile evolved from the Strategic Defense Initiative's ERINT missile, and so it is dedicated almost entirely to the anti-ballistic missile mission.Due to miniaturization, a single canister can hold four PAC-3 missiles (as opposed to one PAC-2 missile per canister).The PAC-3 missile is also more maneuverable than previous variants, due to 180 tiny pulse solid propellant rocket motors mounted in the forebody of the missile (called Attitude Control Motors, or ACMs) which serve to fine align the missile trajectory with its target to achieve hit-to-kill capability.