programs used by the US military.--Stephen V Cole

While the U.S. Air Force battles to obtain enough money to get the F-22 fighter and Joint Strike Fighter built, it has seven more experimental aircraft being tested, or getting ready for tests. Two, the X-32 and X-35 are attempts to develop a replacement for the vertical take off Harrier used by the marines. The Harrier was designed over thirty years ago, and the replacement prototypes are faster and carry more bombs. Computers, rather than the pilot, do most of the work. This makes the engineers a bit nervous, which is one reason there are two different prototypes for testing different technical solutions. The X-39 is secret, or it may not exist. Little is known about it. The X-37 is a low orbit satellite that is launched from a larger aircraft, then lands (after as much as a year in orbit) like an aircraft. The X-41 is a guided warhead, launched from a space vehicle or ICBM. It could reach any target on the planet within 90 minutes of launch. The X-42 is another "smart stage" for a satellite launcher. The X-45 is a pilotless bomber. The X-33 is a reusable launcher (no shedding of stages on the way up.) The X-31 is a jet aircraft that can land in a very short space (a hundred meters or so.) The technology from the X-31 is expected to be used in the X-44A, a F-22 modified