David's Sling Makes Direct Hit in Intercept Test


This article first appeared in Aviation Week & Space Technology.

Israeli defense contractor Rafael has validated the David's Sling missile-defense system in an intercept test, when it scored a direct hit on a target vehicle simulating a medium-range rocket.

David's Sling was developed by Israel. Rafael is the prime contractor and development authority, and Raytheon the leading subcontractor and U.S. program lead. The system is an endo-atmospheric weapon, targeting ballistic missiles and medium-range rockets, manned and unmanned aircraft, cruise missiles and guided weapons. An air-launched version is under study.

The Nov. 22 test covered a large area of the Negev desert, to test the weapon's long-range capability. The initial David's Sling unit stands up this year under the Israeli air force's active defense branch. Initial operational capability is slated for 2014.

A test video released by the defense ministry shows the intercept phases. In the first stage the target rocket is launched. The David's Sling multimission radar (MMR) detects the launch and tracks the rocket as it ascends over the horizon. Once the trajectory is determined, the battle management and control (BMC) system calculates the intercept point and orders the fire unit to launch an interceptor. In this intermediate phase the two missiles fly toward each other, with the Stunner intercept missile, developed by Raytheon and Rafael, accelerating rapidly. Upon locating the target with its two seeking sensors (one electro-optic, the other radio frequency), Stunner enters the final intercept course and strikes the target.

The David's Sling system incorporates powerful MMR, BMC and fire units. The Stunner missile is fired from a 12-pack launcher with the aid of a short-burn droppable booster. A multiband seeker (incorporating radar and imaging infrared sensors) optimizes interception under all engagement conditions, including adverse weather and countermeasures. The missile has no warhead, and uses an enhanced hit-to-kill (HTK) mechanism to destroy missiles and maneuvering aircraft. The weapon is designed for maneuverability and speed, and has target-change flexibility.

The Stunner has a unique “dolphin-nose” front section which allows both the radar and IR seeker to look forward and a three-pulse motor. The first two motor pulses accelerate the missile through its midcourse trajectory, where it maintains course to a location and then activates the seeker to acquire the incoming missile. Upon target detection, the missile determines the intercept course, as the third rocket pulse activates to increase speed and maximize kinetic energy on impact.

The missile can change course automatically or by command. The weapon is aerodynamically controlled without thrust vectoring. Two sets of four movable wings are controlled by servo systems fore and aft of the missile motor and driven by commands from the guidance electronic unit in the front section. (A third, fixed set of wings act as flow control vanes for the aft wings.) A data link receives target updates and commands from the ground.

Researchers used the Missile Defense Testbed and other engagement analysis software to simulate a hypothetical threat from a country possessing long- and intermediate-range ballistic missiles to demonstrate benefits of the Stunner. According to the assessment, a ballistic strike force comprising 600 Scud-type missiles and 200 long-range missiles, fired from 60-70 mobile launchers, could in minutes launch tens of missiles in rapid succession. Many would target critical assets, with the impact points of others uncertain, thus requiring complex threat-killing strategies.

Two defensive strategies were compared. In one, an investment of $1 billion in current missiles (e.g., MIM-104C Patriot missiles, upgraded MIM-23B Hawks and the Arrow II), each worth around $4 million, would result in 250 interceptors. To intercept the threats, defenders would need to launch at least 60 missiles, expending almost 25% of assets, against an estimated 10% of enemy inventory. With this strategy, a defensive shield would be gone after four attacks.

In contrast, by deploying David's Sling or a mix of David's Sling and existing interceptors, that same $1 billion would procure 600 Stunner interceptors, each costing less than $1 million, and 100 costlier missiles, which would be saved for special purposes. In this scenario, less than 10% of the defensive shield would be used to repel the threat (10 of the costlier missiles and 50 Stunners) and defenses would be maintained until the attacker runs out of missiles.

David's Sling will be integrated into a multilayered national defense system, receiving constant situational awareness and target updates from sensors and other assets, such as the Arrow Weapon Systems' Green Pine radar, national airspace control system and elevated sensor systems.

The Stunner is designed to be the basis for a next-generation air-to-air missile by removing the launch booster stage.

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Missile Defense