matter of physics; shells fired from a cannon undergo tremendous stress and it is very expensive to build electronics or submunitions that can survive that kind of punishment. The 1980s Copperhead guided anti-tank round is a good example. They got it work (some were used during the Gulf War, no one was impressed), but it was too damn expensive. The 40 ton Crusader is also too heavy to get anywhere in a hurry. It's easier to fly in MLRS or towed 155mm guns. Work will continue on "smart shells" for the thousands of 155mm guns the U.S. already has, and more smart rockets for the MLRS are being developed. But the thing that really was the last straw was the success of the new generation of smart bombs in Afghanistan. These GPS guided weapons were as accurate as any Crusader fired shell, and more destructive. The 2,000 pound JDAM GPS guided bomb can destroy targets the Crusader cannot. And the bombs can be dropped anywhere, while the Crusader has to get within 40 kilometers of the target.
The Department of Defense recently cancelled the Crusader self-propelled artillery system. Crusader weighed 40 tons and cost $15 million each. The entire program was to cost $11 billion. Crusader could fire 155mm artillery shells farther, faster and more accurately than the current 1960s vintage M-109A6 Paladin. The Crusader cancellation is said to be the victim of the end of the Cold War, but it is also a victim of the decades long struggle between the "smart munitions" (like the MLRS rockets with smart munitions and GPS bombs) and "smart weapons" (like the Crusader.) Smart munitions for tube artillery (like the Crusader) never really worked (too expensive to get the stuff to work.) That was mainly a