The U.S. Navy, not unexpectedly, has run into more technical problems developing its new Extended Range Guided Munition (ERGM). This is a 127mm (5 inch) shell for warships (cruisers and destroyers) to use in providing support for ground operations. The ERGM has a range of over a hundred kilometers, and uses GPS guidance and small fins to put the shell to within 30 feet of where it is aimed. ERGM carries submunitions for attacking personnel and armored vehicles. Work on the ERGM began in 1996. The new shell is already four years late, and looks like it wont be ready for service for another three years. Even then, its unlikely to prove very practical. In the 1980s, the U.S. Army developed a similar smart shell for its 155mm guns. Called the Copperhead, it eventually entered service, but was so expensive (nearly $30,000 a shell) and specialized (someone had to shine a laser light off the target), that few were used even when they were available (as they were in the 1991 Gulf War.) The ERGM will cost over $50,000 a shell, and troops on the ground would rather have a $20,000 smart bomb anyway. The biggest problem with ERGM is not going to be making it work. No, the problem will be keeping it working. Each shell has special batteries that have to be replaced every few years, and the electronic and mechanical systems in the shells will face their biggest challenge sitting in a bunker, or deep inside a ship for years at a time. Your ordinary 5 inch shell costs about $200 and takes long terms storage quite well. But ERGM has acquired a life of its own and has already resisted many efforts to kill it.