Defense Technology International - September 2007 - (Page 50) ORDNANCE NAVAL tive—ERGM round is headed for a fourround engineering demonstration firing series in December. This should be followed by a 20-round series of reliability firings, ending in September 2008 and paving the way for a low-rate initial production (LRIP) decision. That will lead to land-based development test firings and integration tests with the Mk 45 Mod 4 gun and its Mk 160 fire-control system, with shipboard tests starting in 2010. After the extremely difficult development of ERGM, producing a bigger, longerrange, rocket-boosted projectile for AGS might seem foolhardy. However, Bond believes that the newer gun is in some ways less risky. The guidance, navigation and control (GNC) electronics are the same size, leaving more space for packaging and protection, and the new gun has been designed by prime contractor BAE Systems to provide smoother acceleration. Lockheed Martin is responsible for the development of LRLAP, and test firings of prototype weapons in summer 2005 were largely successful, achieving a range of up to 63 naut. mi. AGS is a radical gun system with an allelectric, unmanned mount—matching the more-electric systems of the ship itself—including a 300-round automated magazine. The system is designed for a sustained rate of fire of 10 rounds per minute, with the gun elevating to a vertical position for loading. The turrets match the low radar crosssection design of the DDG-1000. So far, the LRLAP is the only projectile that AGS will fire: in order to let the GPS acquire a satellite signal more quickly, the barrel has less twist in the lands and grooves that impart spin to the round, so the ability to shoot an unguided projectile has been lost. AGS and LRLAP have completed some successful trials and the first gun, mount and LRLAP projectiles for development testing are now being designed. The next test firings will not take place until midFY 2009. The program office’s goal is to have the weapon ready for integration in FY 2011. Currently, the two authorized DDG1000 ships are due to be delivered in FY 2012 for operational evaluation starting in the last quarter of FY 2013. A key feature of both ERGM and the AGS is known as MRSI (multiple rounds, simultaneous impact). By adjusting the elevation angle and the projectile’s flight path, the time of flight to a given point can be changed, making it possible for up to six rounds per gun—12 rounds per salvo from the two-gun DDG-1000—to impact within a second. This is why Bond can compare the effectiveness of a single DDG-1000 to a Marine artillery battalion with 18 guns. Normally, one of three batteries in the battalion is moving at any one time, leaving 12 guns to fire, and since individual rounds cannot achieve MRSI, the ship’s two guns deliver an equivalent salvo. Over the longer run, too, the AGS has a higher sustained rate of fire than conventional artillery. However, this capability comes at a cost that makes the AGS and DDG-1000 controversial. In the long evolution of the ship design from the DD-21, through the DD(X) and into the DDG-1000, displacement has been reduced and features removed to save money. The initial design envisaged a magazine capacity of 1,200-1,500 rounds, but that was first cut to 920 rounds and then to the current 600 (that is, one 300-round magazine per mount). In one sense, 600 rounds is a lot; in another sense, it is only 30 min. of firing. According to analyst Robert Work of the Washington-based Center for Strategic and Budgetary Assessments, the Navy has developed an “infinite magazine” concept in which DDG-1000s are resupplied with palletized ammunition that the ships receive by helicopter lift without leaving the firing line. Even with the reduced weight, the DDG1000 is the biggest U.S. Navy surface combatant since the 1950s nuclear cruiser USS Long Beach. And, as Work points out, there is a dichotomy between the DDG-1000’s stealthy design and a concept of operations that involves routine approaches by very non-stealthy helicopters. Also, the weapon load represents a challenge for any helicopter operation. Even discounting the mass of pallets and propellant, a full load of LRLAPs represents 16 sorties by today’s CH-53E, the heaviest Navy/Marine helicopter, and eight deliveries by the forthcoming CH-53K. Moreover, the CH-53E fleet is vastly overstretched, and the CH-53K will not even begin to be operational until 2015. Further complicating the picture is the fact that based on current plans, the DDG1000 ships will remain a small class. The Navy intends to adapt the design to the CG-21 cruiser optimized for air and missile defense, with the two AGS mounts replaced by The Mk 45 Mod 2 missile-launch tubes. As a result, gun is on the latest the entire AGS/LRLAP program Burke-class destroyis likely to end up arming seven ers. Rocket-boosted platforms at most. projectiles make it In Europe, the main focus has effective for offshore been on developing improved fire support. rounds for in-service 127-mm. guns, since Germany has abandoned plans for 155-mm. armament in its new frigates. The largest new-technology program in the field of naval gunfire support is the development by Oto Melara of Italy of the Vulcano family of extended- and longrange sub-caliber munitions for that company’s family of 127mm. naval guns, as well as for the Mk 45 gun family. The slender sub-caliber projectiles do not carry the same explosive load as the ERGM, but obtain greater range without rocket boost. Phase 1 of the Vulcano program is backed by the Italian and BAE SYSTEMS 50 DEFENSE TECHNOLOGY INTERNATIONAL SEPTEMBER 2007 www.aviationweek.com/dti http://www.aviationweek.com/dti
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