随着苏联反潜战技术在六十年代末和七十年代初的改进,射程仅2880海里的海神导弹使美国的潜艇部队不得不深入到苏联的有效巡逻海域之内活动。因此,洛克希德导弹和空间公司研制出了三叉戟Ⅰ(C4)导弹,这种导弹的结构尺寸与海神的相同,但在携带14个再入飞行器的全负载条件下,射程增加到4600海里。根据第二阶段限制战略武器 With Soviet anti-submarine warfare technology improved in the late 1960s and early 1970s, the Neptun missile, which had a range of only 2,880 nautical miles, had forced the U.S. submarine force to penetrate into the effective patrolling waters of the Soviet Union. As a result, Lockheed Missile and Space Corporation developed the Trident I (C4) missile, which is the same size as the Poseidon but increases its range to 4,600 nautical miles at full load with 14 Reentry Vehicles . According to the second phase of the restriction of strategic weapons