SBX-1 is the only operational radar system mounted on a non-ship platform and forms part of the U.S. Ballistic Missile Defense System. It is designed to detect and generate precise data on launched ballistic missiles, and after warhead separation, determine which objects are decoys or debris and which are actual warheads.
Developed by Raytheon, the X-Band Radar (XBR) is housed within a 31 x 37-metre dome and is considered the largest and most advanced system operating in the X-band (8-12.5 GHz). Its octagonal antenna has a physical aperture of 384 m² and an active aperture of 248 m², built from 45,000 transmit/receive modules, and can rotate 270° horizontally and 85° vertically at 5-8° per second.
The radar’s optimal operating temperature is maintained by a liquid cooling system circulating 3,634 litres per minute of propylene glycol solution. SBX-1 weighs 1,814 tonnes, with the dome alone weighing 8,164 kg, and is mounted on a platform with a displacement of 32,690 tonnes, increasing to over 50,000 tonnes when ballast tanks are flooded.
Power is supplied by eight Caterpillar C280-16 generators, each producing 5,060 kW, while movement is provided by eight Wärtsilä FS 2150-663 azimuth thrusters, each with a 3,300 kW electric motor, allowing a maximum speed of 9 knots. The platform supports a crew of 85, carrying sufficient fuel and provisions for 60 days of independent operation.
The base platform is a fifth-generation Moss CS 50 semi-submersible oil rig built by the Vyborg Shipyard in Russia’s Leningrad Oblast. After construction and delivery in 2002, it was converted for military use at the Keppel AmFELS shipyard in Texas, with Boeing Integrated Defense Systems designing the project.
The radar was installed on 3 April 2005 at Kiewit Offshore Services in Corpus Christi, Texas, and covered with its dome a month later. Although its official home port is Adak Island, Alaska, SBX-1 is stationed in Pearl Harbor, Hawaii, where it was moved in 2009 after North Korean missile threats, and it recorded its longest deployment at sea of 661 days, ending in October 2022.
