UGM-73海神弹道导弹为美国海军的第二种弹道飞弹系统，动力来自2节固态燃料引擎。它自1972年开始接替北极星飞弹，带来弹头和精准度的重大进展。它的后继型号是1979年的三叉戟I和1990年的三叉戟II。

The UGM-73 Poseidon missile was the second US Navy nuclear-armed submarine-launched ballistic missile (SLBM) system, powered by a two-stage solid-fuel rocket. It succeeded the UGM-27 Polaris beginning in 1972, bringing major advances in warheads and accuracy. It was followed by Trident I in 1979, and Trident II in 1990.