In the U.S.- led airstrikes against Afghanistan, the satellite-guided bombs called Joint Direct Attack Munitions, or JDAMs, were widely used for the first time. The results surprised even their advocates as accuracy increased dramatically. Steered directly to their target through satellites, these “smart bombs” are safer and more accurate than the laser-guided bombs used in the Gulf War and a huge improvement on the gravity bombs that dominated aerial bombardment during the Vietnam War.
“JDAMS dont' require somebody in an aircraft to to hold a laser beam to target and therefore increase pilot safety as they don’t have to hang around after they fire,” said William Martel, a professor at the Naval War College.
JDAMs debuted in the Kosovo conflict, tranforming the accuracy of tactical and strategic warplanes. Unlike the old gravity bombs, or “dumb bombs,” which simply drop to the ground when released, JDAMs are steered to their target. Before the JDAM is fired, it is programmed with its target’s coordinates and when the aircraft carrying the bomb reaches the specified release point the JDAM is fired.
Once let go, the bomb’s Inertial Navigation System/Global Positioning System (GPS) takes over and guides the bomb to its target. An aerodynamic design also helps the bomb maneuver through the air.However, the JDAM does have an Achilles heel.
“While the JDAMs are useful weapons, their dependency on Global Positioning System may prove to be risky,” said David Silbey, a military historian at Alvernia College, in Reading, Pa. “If that gets jammed, we have a problem.”
Also, fatal errors can result if the wrong GPS coordinates are entered as was the case in Afghanistan when a bomb accidentally crashed on American special forces unit.