The U.S. Navy has successfully tested in-flight targeting for F-18 aircraft carrying SLAM-ER missiles. These weapons are improved versions of the original SLAM, first used during the 1991 Gulf War. The 1400 pound missile has a range of 270 kilometers and is designed for destroying ships. But because of it's accuracy, it can take out land targets as well with its 500 pound warhead. Guidance is similar to JDAM (GPS and inertial guidance system), but with a heat seeker and final adjustments via a data link by the pilot any aircraft equipped with SLAM control equipment. In the past, the SLAM had to be programmed to fly a specific course before take off. Being able to reprogram the missile in flight is another capability required for weapons used via the battlefield Internet. This allows a satellite, aircraft or UAV to pick up a target (like an enemy ship hidden in a cove), and pass that data to an aircraft carrying a SLAM-ER. Since the missile can hit targets 270 kilometers away, enemy ships or land targets in a large area are vulnerable once SLAM-ER aircraft are in the air. The missiles cost $500,000 each.