What is the purpose of the SM-3 Standard Missile?

The SM-3 Standard Missile is primarily designed as a missile defense system to intercept short to intermediate range ballistic missiles. It plays a critical role in the layered ballistic missile defense strategy employed by the U.S. Navy and its allies. The missile utilizes advanced technologies, including guidance systems, to track and destroy incoming threats during their midcourse phase of flight, often outside the atmosphere. This capability is integral to protecting both naval vessels and allied territories from ballistic missile attacks, effectively enhancing national and regional security.

In contrast, the other options describe different types of missile systems that do not share the SM-3's specific focus on ballistic missile defense. Long-range air-to-air missiles and cruise missiles are developed for entirely different combat roles, such as engaging aerial targets or attacking surface ships, respectively. Similarly, surface-to-surface guided missiles are intended for naval engagements rather than intercepting missiles, which distinctly sets the SM-3 apart in its operational purpose.