The MGM-166 LOSAT (Line-of-Sight Anti-Tank) was a United States anti-tank missile system designed by Lockheed Martin (originally Vought) to defeat tanks and other individual targets. Instead of using a high explosive anti-tank (HEAT) warhead like other anti-tank missiles, LOSAT employed a solid steel kinetic energy penetrator to punch through armor. The LOSAT is fairly light; it was designed to be mounted onto a Humvee light military vehicle while allowing the vehicle to remain air-portable. LOSAT eventually emerged on an extended-length heavy-duty Humvee with a hard-top containing four KEMs used by special operations. Although LOSAT never "officially" entered service, it was used for the smaller Compact Kinetic Energy Missile. History HVM LOSAT developed out of an earlier Vought project, the HVM. HVM was a multi-platform weapon supported by the US Air Force, for the Fairchild Republic A-10 Thunderbolt II, and by the US Army and US Marine Corps, for helicopters and other vehicles. HVM offered performance similar to existing systems like the AGM-114 Hellfire but offered a semi-fire-and-forget operation through the use of FLIR tracking and guidance commands sent to it via a low-power laser. It could be carried on any platform that had FLIR support, with the self-contained command guidance system able to be carried externally, or potentially integrated into existing target designators. With the end of the Cold War, the Air Force pulled out of the project, and development work on HVM appears to have ended in the late 1980s. AAWS-H At about the same time, in 1988, the Army released a new requirement for a ground-based anti-tank system, known as Advanced Anti-Tank Weapon System - Heavy, or AAWS-H for short. AAWS-H specified an air-liftable lightweight system with the capability to knock out any existing or near-future tank outside its own gun range. The TOW missile could be guided from concealed locations, but did not offer the needed range and its relatively slow flight speeds (~250 m/s versus 1650 m/s for HVM) left it vulnerable to counterattack from the target while the missile was in flight. To fill AAWS-H, Vought developed a slightly larger extended-range version of HVM known as Kinetic Energy Missile (KEM), while their partner, Texas Instruments, provided a new FLIR targeting system that they were already working on as a TOW upgrade. Several vehicles were studied to mount the system, including the front-runner M2 Bradley, as well as the M8 Armored Gun System. However, in order