July 31, 2011: A U.S. Minuteman III ICBM (InterContinental Ballistic Missile) recently failed a test launch. The U.S. Air Force regularly conducts quality control tests on its fleet of 450 Minuteman III missiles. A successful test sends the missile 7,600 kilometers away, towards the central Pacific, and the warhead (the nuclear weapon replaced with tracking instruments) lands, usually where it is supposed to, near the Marshall Islands.

The Minuteman third stage, that long contained three 200 kg (440 pound) nuclear weapons, has been replaced with a new one containing a single warhead. The Minuteman III is 18.2 meters (59.8 feet) long, 1.7 meter (5.5 feet) in diameter and weighs 35 tons. Minuteman III has been in service since 1970. Until production ceases in 1978, 530 were produced. Since then, there have been several upgrades. The Minuteman III is expected to remain in service until 2020, at which point it will be replaced by a new missile design. Current disarmament treaties have the United States reducing nuclear warheads to fewer than 2,200 in the next few years.

Last year, the Minuteman test program was interrupted by a "mechanical problem" that delayed testing for seven months. The problem was discovered after a missile, selected at random from those stored in Midwest silos, was brought to Vandenberg Air Force Base in California. There, it was placed in a silo, and readied for firing. But during all that, a problem was encountered. The air force won't say what exactly the problems was, or if it was something common to other Minuteman missiles.

This kind of testing is not as realistic as what the Russians do, which is to just pick a missile at random, remove the nuclear warhead and replace it with one full of monitoring and radio equipment, and then fire it. The U.S. can't do that because American silos are surrounded by inhabited areas. Thus if the missile ran into trouble, and had to be destroyed (all such missiles are equipped with explosives for this, that can be set off by remote control), the debris could come down on people. Most Russian silos are in more isolated areas, and Russians are more tolerant of their government showering them with missile debris. The recent Minuteman test failure resulted in the missile was destroyed, with the debris falling into the Pacific.

American ICBM tests are different in other ways. For example, a test four years ago was unique because for the first time, the test silo had the 105 ton doors closed, and then blown open just before launch. Repairing the doors is expensive, so the doors are usually kept open during preparations for the test, and plastic sheeting spread over the open silo to keep rain out. But a previous test was screwed up by a heavy rain, which flooded, and damaged the silo despite the plastic sheeting. Another first for the test four years ago was the use of GPS guidance in the test warhead.

The tests are a form of quality control, and the current problems are actually beneficial. The test preparation process often uncovers problems that would cause the missiles to fail if used in a combat situation.