The Extended Range Guided Munition was a precision guided rocket-assisted 5-inch (12.7 cm) artillery shell development by Raytheon for the U.S. Navy. The program was cancelled in March 2008 after twelve years of development and over 600 million dollars in funding.[1] The developmental round was designated EX 171.[2] ERGM consisted of three major subsections; propulsion (rocket motor), warhead, and Guidance, Navigation and Control section. ERGM is fired from the 5 inch 62 Caliber Mark 45 gun Mod 4 at which point the fins deploy,rocket motor would ignite and lift the munition to at least 80,000 feet (24 km) when the canards would deploy and guide the ERGM to the target based on GPS guidance. It was to be used on Arleigh Burke class destroyers (hulls DDG-81 through 112).
Despite the long development time the ERGM never worked as reliably as the older but significantly less expensive laser guided M712 Copperhead. During development, the ERGM failed several tests in which the tail fins failed to deploy at launch, rocket motors did not ignite or the electronic components did not survive the stress of being shot from a deck gun.[3] Rising cost was another likely factor in cancellation. The unit cost of the shell more than tripled, from $45,000 in 1997 to $191,000 by 2006, reducing the projected buy from 8,500 to about 3,150(in contrast the Copperhead average unit production price was about $30,000). BTERM is another U.S. Navy developmental round that includes GPS guidance in an artillery shell; it too was terminated in 2008 after 4+ years of development by ATK. XM982 Excalibur is a U.S. Army round in development. A similar shell as part of the Vulcano line of projectiles is on the horizon from the Oto Melara division of Finmeccanica of Italy. The reported range of these projectiles is 120 km for the 155mm calibre and 80 km for 127mm calibre, which is already being installed on some German Navy vessels.[4]
Contents |