Life just became harder for the crews of surface-to-air missile (SAM) systems. The U.S. Air Force is equipping Predator UAV aircraft with HARM missiles (that home in on the transmission of a SAM system radar) to better destroy enemy air defenses. Currently, most SAM systems try to shut down their radars when they detect, or suspect, HARM equipped warplanes are in the area. But the predator is harder to detect on radar, especially if it comes in low and slow. And the Predator can hang around, literally, all day, until the SAM radars are turned on again, or are found by the prowling predators. While most existing HARM missiles weigh nearly half a ton, the Predators favorite missile, the hundred pound Hellfire, can be equipped with a guidance system that homes in on radar signals. Predators can also seek out enemy radar sites and missile launchers, and knock them out with Hellfires. This was done with AH-64 helicopter gunships against Iraqi radars in 1991.