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Sea-based X-Band Radar (T-SBX-1)


The first U.S. Navy Sea-based X-Band Radar.

(T-SBX-1: displacement 32,690; length 389'; beam 238'; speed 8 knots; complement 83; armament none; class Sea-based X-Band Radar)

Sea-based X-Band Radar (T-SBX-1) was constructed in two Texas shipyards, and extensive sea-trials carried out in the Gulf of Mexico and the Pacific Ocean. She was first deployed with the Missile Defense Agency (MDA) in 2006.

Sea-based X-Band Radar is an advanced X-band radar mounted on a mobile, ocean-going, semi-submersible platform that provides an advanced capability to the Ballistic Missile Defense System (BMDS). Her ocean-spanning mobility allows the radar to be repositioned as needed, increasing the MDA’s ability to conduct operational and realistic testing of the BMDS, while providing an operational capability to the combatant commands. Sea-based X-Band Radar acquires, tracks, and discriminates the flight characteristics of ballistic missiles while the incoming threat missiles are in flight, discriminates between the hostile missile warheads and any countermeasures, and provides that data to interceptor missiles so that they can successfully intercept and destroy the threat missiles before they reach their targets.

The vessel is based on a fifth-generation semi-submersible oil drilling platform. Sea-based X-Band Radar is twin-hulled, self-propelled, and relatively stable in high winds and turbulent sea conditions. Larger than a football field, the main deck houses living quarters, workspaces, storage, power generation, bridge, and control rooms while providing the space and infrastructure necessary to support the radar antenna array, command, control, and communications suites, and an In-flight Interceptor Communication System Data Terminal, which provides missile tracking and target discrimination data to interceptor missiles.

Sea-based X-Band Radar (T-SBX-1) 2006-MSC, 1
Sea-based X-Band Radar’s bulbous radar dome and large platform are unmistakable even at a distance. (Unattributed or dated U.S. Navy photograph, Ship Inventory, MSC)
Sea-based X-Band Radar (T-SBX-1) 2006-MSC, 2
A close-up of Sea-based X-Band Radar moored gives some indication of her massive size, and of the large platform based upon oil rigs that provides her some measure of stability in heavy seas. (Unattributed or dated U.S. Navy photograph, Ship Inventory, MSC)

On 21 February 2008, Sea-based X-Band Radar helped guided missile cruiser Lake Erie (CG-70), Capt. Randall M. Hendrickson in command, shoot down a non-functioning National Reconnaissance Office satellite from the cruiser’s operating area in the Pacific Ocean. The satellite proved an especially challenging target because it traveled in orbit rather than a ballistic trajectory, and at a high speed. Sailors and civilian technicians consequently modified the ship’s Aegis weapon system and Standard SM-3s, and the crew repeatedly rehearsed intercepting the satellite. “By the time we did this, we had seen it a hundred times,” Lt. Cmdr. Drew Bates, the cruiser’s weapons systems officer, asserted. “We were practicing what to do in case things go wrong. Fortunately nothing went wrong. This went just the way it was designed to happen…”

During the forenoon watch on 21 February Lake Erie received Secretary of Defense Robert M. Gates’ approval to splash the satellite. The ship launched a Standard that hit the satellite at an altitude of approximately 153 nautical miles as it hurtled toward the earth at 17,000 mph. Hendrickson recalled that when the missile’s seeker opened its eyes it had the satellite “right dead center,” and that many of the crewmembers cheered when the Standard struck the satellite. The missile ruptured the fuel tank, dissipating the nearly 1,000 pounds of hazardous hydrazine propellant. Video depicted the missile hitting the satellite, and a fireball and vapor cloud or plume erupting from the impact. “The intercept occurred…We’re very confident we hit the satellite,” Gen. James E. Cartwright, USMC, Vice Chairman of the Joint Chiefs of Staff, told reporters during a press briefing at the Pentagon. “We also have a high degree of confidence that we got the tank.”

“The radar scope went wild,” Hendrickson elaborated. “At that point, there was a lot of debris, a lot of pieces and…we thought we had a pretty good impact.” Aircraft and additional radars and sensors ashore confirmed the hit. Radar sweeps of the satellite’s debris field revealed that no objects larger than a football survived the explosion, and these burned up as they fell into the earth’s atmosphere. Guided missile destroyer Decatur (DDG-73) also took part in the operation.

On 5 June 2008, Sea-based X-Band Radar took part in Glory Trip 197, a target of opportunity test over the Pacific. The mobile platform, working with Lake Erie, the Upgraded Early Warning Radar at Beal AFB Calif., and a transportable AN/TPY-2 radar, successfully detected and tracked a Minuteman III long-range missile. The Naval Sea Systems Command Port Hueneme Shipboard Test Team, led by Stanley Williams and James Jones, provided technical, and test and evaluation support. Williams explained that “once again America's finest, those that serve, continue to demonstrate their technical prowess, and tactical ability while meeting the challenges of ballistic missile defense. I am in awe of the Lake Erie sailors that proudly serve.”

Sea-based X-Band Radar participated in another such exercise on 8 December 2008. A threat-representative target missile was launched from Kodiak, Alaska, at 1104. Several radars tracked the missile including Sea-based X-Band Radar, a transportable AN/TPY-2 radar located in Juneau, Alaska, an Aegis ship with SPY-1 radar, and the Upgraded Early Warning Radar at Beale. Each sensor sent information to the fire control system, which integrated the data together to provide the most accurate target trajectory for the interceptor. At 1123 the ground-based interceptor was launched from the Ronald W. Reagan Missile Defense Site, located at Vandenberg AFB Calif. The interceptor’s exoatmospheric kill vehicle was carried into the target’s predicted trajectory in space, maneuvered to the target, performed discrimination, and intercepted the threat warhead. The exoatmospheric kill vehicle was the component that collided directly with a target warhead in space to perform a “hit to kill” intercept, using only the force of the collision to totally destroy the target warhead. The initial data indicated that all of the components performed as designed. The test marked the 37th successful hit-to-kill intercept of 47 attempts since 2001 for the BMDS.

The MDA transferred Sea-based X-Band Radar to the Military Sealift Command (MSC) on 22 December 2011. The MSC operates and maintains the vessel, and coordinates logistics support and port services, but the agency retains responsibility for the X-band radar. Beginning in fiscal year 2015, the ship shifted to a test and operations support status. She can be deployed as needed to support both testing and defensive operations for the BMDS.

Detailed history pending.

Mark L. Evans

11 January 2016

Published: Wed Jan 13 08:50:49 EST 2016