Sea-based X-band Radar

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The Sea-Based X-Band Radar underway.

Sea-Based X-Band Radar is a floating, self-propelled, mobile radar station designed to operate in high winds and heavy seas. It is part of the United States Government's Ballistic Missile Defense System.

The Sea-Based X-Band Radar is mounted on a 5^th generation Norwegian-designed, Russian-built CS-50 semi-submersible twin-hulled oil-drilling platform. The hull was originally built at Vyborg Shipyard, hull number 101. Conversion of the platform was carried out at the AmFELS yard in Brownsville, Texas; the radar mount was built and mounted on the platform at the Kiewit yard in Ingleside, Texas, near Corpus Christi. It is based at Adak Island in Alaska but can roam over the Pacific Ocean to detect incoming ballistic missiles. The platform is classed by ABS and has the IMO number of 8765412.

1 Specifications
2 Details
3 References
4 External links

[edit] Specifications

Platform length: 116 meters (380 feet)
Platform height: 85 meters (280 feet) from keel to top of radar dome
Cost: $900 million
Crew: Approximately 75-85 members, mostly civilian contractors
Radar range: Classified, but probably about 5,000 km (3100 miles) against ICBM warheads
Displacement: 50,000 tons

[edit] Details

The platform is part of the Ground-Based Midcourse Defense (GMD) system being deployed by MDA. Being sea-based allows the platform(s) to be moved to areas where they are needed for enhanced missile defense. Fixed radars provide coverage for a very limited area due to the curvature of the Earth. The primary task SBX will carry out is discrimination (identification) of enemy warheads from decoys, followed by precision tracking of the identified warheads.

The platform has many small radomes for various communications tasks and a central, large dome that encloses and protects a phased-array, 1,814 tonnes (4,000,000 pound) X band radar antenna. The radar is described as being 384 square meters, with "well over" 30,000 transmit-receive modules, which are arranged in a widely-spaced configuration. This configuration allows it to support the very-long-range target discrimination and tracking that GMD's midcourse segment requires. The array requires over a megawatt of power.

The passive electronically scanned array radar is derived from the radar used in the Aegis combat system, and is a part of the layered ballistic missile defense (BMDS) program of the United States Missile Defense Agency (MDA). One important difference from Aegis is the use of X band in the SBX. Aegis uses S band, and Patriot uses the higher-frequency C band. The X band frequency is higher still, so its shorter wavelength enables finer resolution of tracked objects. The radar is designed and built by Raytheon Integrated Defense Systems for Boeing, the prime contractor on the project for MDA.

The radar is described by Lt. Gen Trey Obering (director of MDA) as being able to track an object the size of a baseball over San Francisco in California from the Chesapeake Bay in Virginia, approximately 2900 miles. The radar will guide land-based missiles from Alaska and California, as well as in-theatre assets.

The CS-50 semi-submersible platform on which the radar is mounted was built as the "Moss Sirius" at the Vyborg shipyard in Russia for Moss Maritime (now part of the Saipem offshore company, which is a subsidiary of Italian energy corporation Eni S.p.A.). It was purchased for the Sea-based X-band Radar project by the Boeing company, outfitted with propulsion, power and living quarters at the AmFELS shipyard in Brownsville, Texas, and integrated with the radar at the Kiewit yard in Ingleside, Texas.

The first such vessel is scheduled to be based in Adak Island, Alaska, part of the Aleutian Islands. From that location it will be able to track missiles launched toward the US from both North Korea and China. Although her homeport is in Alaska, she will be tasked with moving throughout the Pacific Ocean to support her mission. The name given to the SBX platform, "SBX-1", indicates the possibility of further units of the class; in circumstances when a vessel is required to be continually on duty over a long period of time, common naval practice is to have at least three units of the type available. Three further platforms of the CS-50/Moss Sirius design were under construction or contract at the Severodvinsk shipyard in Russia as of early 2007, but as of that time it was unknown whether they would be purchased by the US for more SBX radars or sold to other buyers.

On March 20, 2007, SBX-1 successfully tracked an inert ICBM warhead fired from Vandenberg Air Force Base in California to Kwajalein Atoll.

On February 11, 2008, SBX-1 was placed in close vicinity to the shoot-down area of the USA 193 satellite. The following NOTAM was generated:

A0601/08 - QXXXX SBX-1, A SURFACE VESSEL TESTING A HIGH POWERED X BAND RADAR
SYSTEM WILL BE OPERATING IN THE VICINITY OF 2700N/16300W. THE VESSEL ALSO HAS
A SEARCH RADAR ON BOARD FOR DETECTING AIRCRAFT WITHIN APPROXIMATELY 81NM OF
THE VESSEL. IF AIRCRAFT ARE DETECTED WITHIN 8.5 NM OF THE VESSEL TESTING OF
THE HIGH POWERED RADAR SYSTEM WILL BE SUSPENDED. WIE UNTIL 05 MAR 23:59 2008.
CREATED: 11 FEB 13:55 2008