 Complete the following phrase:  Lockheed Martin ALHTK sometimes spelled Lockheed Martin Air Launched Hit To Kill was a Lockheed Martin program sponsored by the USAF and Missile Defense Agency. ALHTK mounted the PAC-3 missile on the wing of an F-15 by using an external shell in the shape of a fuel tank to house the PAC-3 missile. As a surface to air missile system the PAC-3 missile has been used successfully in 