In the missile called a "SAM", it's what the "A" stands for
The next modernisation, called the S-300PMU (Russian -300, US DoD ... 
Its first installation and sea trials were on a Kara class cruiser and it is also 
installed... [DOC] [TLE] Project Nike - Wikipedia [PAR] The missile must "lead" the target to ensure the target is hit before the missile 
depletes its fuel.