There are currently some 75 different cruise missile designs in use, totaling over 80,000 missiles. About 90 percent of these missiles have a range of less than a hundred kilometers. There are at least 42 new cruise missile designs in development. At least nine nations are about to put new land attack cruise missiles into service, having a range of 100-1000 kilometers. The major problem with cruise missiles is that, because they fly so low, they cannot be spotted by ground radar until they are about thirty kilometers away. Higher flying bombers can be spotted 100-200 kilometers away. With GPS technology, cruise missiles can be very accurate. Modern cruise missiles are often shipped from the factory in containers that both store the missiles, and monitor their readiness, and also serve as launching tubes. It is feared that these low maintenance, and easy to use, missiles might get into the hands of terrorists.