Final answer:
Surface-to-air missiles are used on ranges that do not permit cross-range firing, providing ground-based defense against aircraft or other missiles, and have become essential with the development of ICBMs during the 1950s.
Step-by-step explanation:
On ranges that do not permit cross-range firing, surface-to-air missiles (SAMs) must be used. These missiles are designed for ground-based defense against aircraft or other missiles. They are a pivotal part of a country's air defense system, particularly when long-range, air-to-air, or short-range missiles are not suitable for use either due to range restrictions or safety reasons.
During the escalation of armaments in the 1950s, as the United States and the USSR developed intercontinental ballistic missiles (ICBMs), the importance of powerful air defense systems became more paramount. The ICBMs allowed for the launching of missiles armed with nuclear warheads from a home territory to a target without the need for air combat. Hence, robust SAMs became indispensable for intercepting incoming threats that could not be reached by air forces. Surface-to-air missiles play a critical role in modern warfare where distances are vast, and threats can emerge from numerous directions.