Sea-Based X-Band Radar

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Sea-Based X-Band Radar
Sea-Based X-Band Radar in Fahrt
Sea-Based X-Band Radar in motion
Ship data
Flag United StatesVereinigte Staaten United States
Call sign AAMD
Whereabouts on the move
Ship dimensions and crew
116 m (Lüa)
Crew 75
IMO No.: 8765412

Sea-Based X-Band Radar runs into Pearl Harbor on the deck of the Blue Marlin January 9, 2006 en route to Adak Island, Alaska.

The Sea-Based X-Band Radar(SBX also SBX-1) is a floating, mobile, self-propelled radar station capable of operating in severe storms and high seas. It is part of the United States Ballistic Missile Defense System. The platform’s IMO number is 8765412 and its call sign is AAMD.

The sea-based X-band radar is mounted on a fifth-generation CS-50 semisubmersible double-hull oil drilling platform designed in Norway and built in Russia. The platform conversion was performed by AMFELS Shipyard in Brownsville, Texas; the radome was designed and built on the platform by Kiewit Corporation in Ingleside, Texas. It is stationed near Adak Island, Alaska, but can be used throughout the Pacific to detect attacking ballistic missiles, particularly intercontinental ballistic missiles (“ICBMs”).

Structure and use

View of the AESA antenna inside the radome

The platform is part of the Missile Defense Agency’s (MDA) Ground-Based Midcourse Defense (GMD). Because it is sea-based, it can be moved to where it is most needed to expand defenses against missile attacks. The main task of the SBX will be to distinguish enemy warheads from dummies also sent out in an attack, as well as to precisely track the trajectory of the identified warheads.

The platform has many small radar domes for communications purposes and a large central dome enclosing a 2400 ton X-band AESA radar. This radar has well over 45,000 transmit/receive modules in an area of 384 square meters, 248 square meters of which is pure antenna area, arranged in a wide-area configuration designed to support the GMD’s very long-range target detection and tracking missions for the medium flight phases of intercontinental ballistic missiles. The radar has over one megawatt of electrical power. It covers a sector of 2 to 90 degrees vertically and a range of ±270 degrees horizontally through mechanical and electronic alignment.

The radar system used has been developed from the Aegis combat system and is part of the MDA’s multi-stage BMDS (Ballistic Missile Defense) program. An important difference to Aegis is the use of the X-band frequency range (Aegis uses S-band, the Patriot system C-band). The radar was designed and built by Raytheon Integrated Defense Systems for Boeing, the prime contractor for the MDA project.

The director of the MDA, Lieutenant General Trey Obering, states that the SBX can track an object the size of a baseball from the Chesapeake Bay 2900 miles away in San Francisco.

The radar will also guide the anti-missile deployment of missiles stationed in Alaska and California, as well as naval combat units close to the site.

The CS-50 platform was built as “Moss Sirius” at the Vyborg shipyard in Russia for Moss Maritime (now part of the Saipem offshore company belonging to Italy’s Eni). She was purchased by Boeing for the SBX project, fitted with marine propulsion, power supply and crew quarters at the AMFELS shipyard in Brownsville, and fitted with radar at the Kiewit shipyard in Ingleside.

This first SBX system will be stationed on Adak Island, part of the Aleutian Islands, where it can detect approaching missiles from North Korea and China, but can also be deployed throughout the Pacific region. The platform’s name, SBX-1, suggests that more are in the planning stages. Three other CS-50 platforms were under construction at the Sevmash shipyard in Russia in early 2007; however, it is not known whether they are being built on behalf of the United States or other customers.

On March 20, 2007, the SBX-1 successfully captured a (non-armed) warhead of an intercontinental ballistic missile fired from Vandenberg Air Force Base in California to Kwajalein Atoll.

In early April 2013, CNN reported that the SBX-1 system had been deployed to observe North Korea.[1]


  • Platform length: 116 meters (380 feet)
  • Platform height: 85 meters (280 feet) from keel to top of radome
  • Cost: $900 million
  • Crew: Approximately 75, mostly civilians
  • Radar range: Secret, but probably 5000 kilometers against intercontinental missiles.



  • Glen W. Goodman: Big rigs: Large, powerful radar systems underpin U.S. missile-defense efforts. C⁴ISR, March 2006, pp. 26-28.

Web links

Commons: Sea-based X-band radar– Image collection

Individual references

  1. Sea-based radar to watch North KoreaCNN. 1 April 2013. retrieved 1 April 2013.