« Back to List

UGM-133A Trident II

The Trident II (D5) is a three-stage, solid-propellant, inertially guided submarine-launched intercontinental ballistic missile. Attributed with very long range, a high-precision guidance system, and a MIRV (Multiple Independent Reentry Vehicle) warhead, it is probably the most important part of the current nuclear arsenal of the United States.
UGM-133A Trident II


In active service


Manufacturer: Lockheed Martin
1st and 2nd stage booster manufacturer: Thiokol acquired by Alliant Techsystems
1st and 2nd stage booster manufacturer: Hercules Aerospace
3rd stage manufactured by: United Technologies Corp.


Length: 13.58 meters 44.55 feet
Weight: 58 970 kilograms 130 000 pounds
Range: 6 000 nautical miles (11 100 kilometers) (6 900 miles)
Circular Error Probable: ~90 meters ~300 feet
Guidance system: stellar-aided inertial system (precision gyroscopes, accelerometers, a stellar tracker, and computer)
Propulsion: three-stage solid-propellant rocket
Warhead: 6 W88 multiple independently targeted reentry vehicles (MIRVs)
Yield: 475 kilotons (each warhead)


October 1983 - Development contract formally issued (2 years after the first Ohio-class submarine entered service)
Early 1986 - Designation allocated
January 1987 - First launch
March 1989 - First attempted submarine launch (by USS Tennessee (SSBN-734), the first boat of the Ohio class equipped with D5 missiles. The launch failed because of problems with the first stage engine nozzle)
March 1990 - Initial Operational Capability