The Air Force is moving into a multi-year program to test its new X-45A unmanned combat air vehicles. The first X-45A completed its first flight on 22 May; a lazy 14-minute stroll around the NASA Dryden dry lake beds with the landing gear down. A second X-45A has been completed and will fly in a few months. Next year, the two X-45As will begin working together to develop tactics to attack enemy air defenses; the first mock attacks with inert weapons will come in the summer of 2003. By 2005, three X-45As will be conducting full dress rehearsals of attacks on defended targets, opening gaps in the defenses for manned aircraft to exploit. While such aircraft are interesting, the more the Air Force learns about their capabilities, the more it learns about their limitations. It only complicates things further when the manned-fighter Mafia exaggerates every foible into a fatal flaw. UCAVs are not going to be so cheap that they can be thrown around like cruise missiles; enough computer power to replace the man in the cockpit costs serious money. A really capable UCAV could cost nearly as much as a manned fighter. The big savings comes in training. UCAVs can be stored during peacetime, with virtually all training by their remote pilots done in simulators. And more capability means more size, pushing UCAVs to nearly the size of manned fighters. While the X-45A has a 34-foot wingspan and is 26.5 feet long, the aircraft that will enter squadron service in 2008 is the larger X-45B, which has a 47-foot wingspan and is 36 feet long. The X-45B is designed to carry a pair of 1,000-pound GPS-guided bombs; it could also be fitted with a dozen of the new 250-pound guided bombs. Air Force officials are starting to ask themselves if this is enough, or if they want to carry stand-off rocket-powered weapons as well. The X-45B will use the same engine as the F-18 (but only one of them), and will be stealthy. The avionics on the X-45A are on a pallet loaded into the left weapons bay to make it easier to work on them; the X-45B will be designed with its avionics in the main body so it is ready to load weapons and fight. The X-45B Block 10 will have only basic abilities to attack targets and enemy air defenses. Block-20 would be able to react to enemy air defenses that suddenly reveal themselves, responding with air-to-ground weapons. Block-30 will include a directed energy microwave "ray gun" which can burn out enemy radars and electronics. Somewhere along the line, the X-45B will gain an aerial refueling capability, allowing it to stay in the fight as long as it has weapons. And with a microwave gun powered by the fuel, that could mean multi-day missions circling over the enemy, destroying anything detected emitting radio or radar signals.--Stephen V Cole