The ballistic missile threat continues to grow in size and complexity. Current trends indicate that adversary ballistic missile systems, with the integration of advanced liquid- or solid-propellant propulsion technologies, are becoming more mobile, survivable, reliable, accurate and capable of flying longer distances. In 1972, only nine countries possessed ballistic missiles. Today, the number of countries possessing ballistic missiles is over twenty, including hostile regimes with ties to terrorist organizations. Not only are missiles proliferating, but many of the countries acquiring them are making their own improvements to missiles bought on the global arms market and developing their own capabilities to produce them indigenously. Rockets have already been used by terrorist organizations, and missiles and rockets with better guidance systems, longer range, and more destructive power are proliferating.