The Trident II missile is a submarine launched ballistic missile (SLBM) designed by Lockheed Martin Space Systems in the United States. It is armed with nuclear warheads and carried by the Ohio class nuclear-powered ballistic missile submarines. Trident II D-5 was first deployed in 1990 and the US Navy currently plans to keep the missiles in service for the thirty year life of the submarines, until 2027.Trident II is more sophisticated and can carry a heavier payload. It is accurate enough to be a first strike weapon. All three stages of the Trident II are made of graphite epoxy, making the missile much lighter. The D5 missile is currently carried by twelve Ohio class SSBNs. The Trident II is a three-stage, solid-propellant, inertially guided missile whose range is increased by an aerospike, a telescoping outward extension that halves aerodynamic drag. In the post-boost phase, the Trident missile uses stellar sighting to update its position and reduce the drift error inherent in all inertial reference systems. It is considered accurate enough to engage in counterforce strikes.