thus nearly invisible to radar detection. Eventually, all A model GAM-77s were given this modification as well. A dogleg attack: The Hound Dog would have flown along a designated heading (at either high or low altitudes) to a preset location. At that location the missile would have turned left or right and then proceeded to its target. The intention of this maneuver was to attempt to draw defensive fighter planes away from the missile's target. The first air-drop test of a dummy Hound Dog was carried out in November 1958. 52 GAM-77A missiles were launched for testing and training purposes between April 23, 1959, and August 30, 1965. Hound Dog launches occurred at Cape Canaveral Air Force Station, at Eglin Air Force Base, Florida, and at the White Sands Missile Range, New Mexico. The Hound Dog missile's development was completed in only 30 months. North American received a production contract to build Hound Dogs on October 16, 1958. The first production Hound Dog missile was then delivered to the Air Force on December 21, 1959. 722 Hound Dog missiles were produced by North American Aviation before its production of them ended in March 1963. In May 1961, an improved Hound Dog missile was test-flown for the first time. This upgrade incorporated improvements to reduce its radar cross-section. The Hound Dog already had a low head-on radar cross-section because of its highly swept delta wings. This low radar cross-section was lowered further by replacing its nose cap, engine intake spike, and engine duct with new radar-absorbent material components that scattered or absorbed radar energy. It has been reported that these radar cross-section improvements were removed as Hound Dogs were withdrawn from service. The GAM-77A version of the GAM-77 also included a new Kollsman Instruments KS-140 star tracker that was integrated with the N-6 inertial navigation system. This unit replaced the star tracker that had been located in the B-52's wing pylon. The fuel capacity of the GAM-77A was increased during this upgrade. A radar altimeter was added to the missile to provide (vertical) terrain-following radar capability to the Hound Dog. 428 Hound Dog missiles were upgraded to the GAM-77A configuration by North American. 66 GAM-77A Hound Dog missiles were launched for testing and training up through April 1973. In June 1963 the GAM-77 and GAM-77A were re-designated AGM-28A and AGM-28B, respectively. In 1971, a Hound Dog missile was test-flown with a