SHIP

摘要

BRIEFING: The UGM-133A Trident Ⅱ (D5) is a three-stage, solid -propellant, inertially guided fleet ballistic missile carried by the Ohio-class nuclear-powered ballistic-missile submarines (SSBNs). Trident Ⅱ is more sophisticated than the UGM-96A Trident I (C4.), with a significantly greater payload capability. The missile's range is increased by the aerospike, a telescoping, outward extension that reduces frontal drag by about 50 percent. Trident Ⅱ is launched by the pressure of expanding steam within the launch tube. When the missile attains sufficient distance from the submarine, the first-stage motor ignites, the aerospike engine nozzle extends and the boost stage begins. Within about two minutes, after the third-stage motor ignites, the missile is traveling at nearly 20,000 feet per second.