The first successful Nike test was during November 1951, intercepting a drone B-17 Flying Fortress. The first type, Nike Ajax (MIM-3), were deployed starting in 1953. The Army initially ordered 1,000 missiles and 60 sets of equipment. They were placed to protect strategic and tactical sites within the US. As a last-line of defense from air attack, they were positioned to protect cities as well as military installations. The missile was deployed first at Fort Meade, Maryland during December 1953. A further 240 launch sites were built up to 1962. They replaced 896 radar-guided anti-aircraft guns, operated by the National Guard or Army to protect certain key sites. This left a handful of 75 mm Skysweeper emplacements as the only anti-aircraft artillery remaining in use by the US. By 1957 the Regular Army AAA units had been replaced by missile battalions. During 1958 the Army National Guard began to replace their guns and adopt the Ajax system.