The Martin MGM-1 Matador was the first operational surface-to-surface cruise missile designed and built by the United States. It was developed after World War II, drawing upon experience gained with the JB-2, a copy of the German V-1. The Matador was similar in concept to the V-1, but it included a radio-command feature that allowed in-flight course corrections with the aid of the AN/MSQ-1 radar. The line-of-site characteristics of this system limited the guided range to about 250 miles, but the unguided range was over 600 miles. As with all radio communications, it was also prone to enemy radio jamming. In theory the missile could be "handed off" in flight from one guidance station to the next, but in practice this was rarely successful, and deployed missiles did not plan for it. Matador was armed with a nuclear warhead and, at the 200-mile range, had an accuracy of about 1 mile, which made it effective against any large target like troop concentrations or armored spearheads. First flown in 1949, Matador entered service in 1952. Originally known under the War Department's system as SSM-A-1, the missile had several other designations during its lifetime. By the time it was introduced to service, the USAF had been created, and it referred to them as bombers, assigning the designation B-61. It was later redesignated TM-61, for "tactical missile," and finally MGM-1 when DOD introduced its standardized designation system in 1963. The first flight of a Matador took place at White Sands Missile Range on 20 January 1949. The first two production B-61 Matador missiles arrived at Eglin AFB in September 1953, under the control of the 6555th Guided Missile Squadron, for testing. At the end of 1953 the first tactical squadron, the 1st Pilotless Bomber Squadron, was operational, but it did not deploy to Germany until 1954. Later, other squadrons deployed to Korea and Taiwan. The Matador launch crew consisted of eleven members: one launch officer, one crew chief, two warhead techs, two flight control systems techs, two guidance techs, two airframe and engine techs—one of whom doubled as the crane operator and the other as the launcher tech, and one booster rocket tech. Since the missile was at least theoretically "mobile," all launch equipment was mounted on trucks and trailers. As a result, in addition to their primary duties, most crew members were also drivers. Additionally, there were similarly-sized guidance crews on remote sites, and a maintenance staff for the missiles, the guidance equipment, and the vehicles. Because of the number of people required to support the missile, a "mobile" Matador squadron with five launch crews became cumbersome. As a result, the squadrons were soon deployed at fixed sites and the idea of mobile missiles was abandoned. A typical missile launch site had an active, or "hot" pad on which was kept the missile most ready to launch. This pad was manned by the on-duty launch crew. An alert-ready missile could be launched in 6-15 minutes, depending on the proficiency of its crew. The site usually had a backup pad, containing a missile that required a little more effort to launch. That pad was manned by the standby crew, and if they were on site, they could launch their missile in 20-30 minutes. There was sometimes a third pad, but on a day-to-day basis, it seldom had a missile on it. Production totaled 1,200 missiles, the last of which was removed from active service in 1962. Replacing it was the Mace missile, a much improved version of the Matador. At a glance, the two can be distinguished by the Matador’s pointed nose and the Mace’s rounded one. The Martin Mace was designated TM-76A and TM-76B (TM for tactical missile) until 1963, then MGM-13A for Mobile Ground Launched Missile and CGM-13 for Coffin Ground Launched Missile. Development began in 1954. Compared to Matador, the Mace had a longer fuselage, shorter wings, greater range, and was heavier. Mace MGM-13A was launched from a translauncher (transporter erector launcher) and the MGM-13B was launched from an underground bunker. Unlike the radio-guided Matador, Mace used ATRAN (Automatic Terrain Recognition And Navigation), a radar map-matching system in which the return from a radar scanning antenna behind the missile’s domed nose was matched with a series of "maps" carried on a 35mm film strip on board the missile. The ATRAN guidance system was difficult to jam and was not range-limited by line-of-sight like the Matador, but initially its range was restricted by the availability of radar maps of enemy territory. Eventually, these radar maps were constructed from topographic maps. The Mace was first launched in 1956 and the missile could reach targets over 500 miles away at low level (as low as 750 feet), and nearly 1,300 miles away if flying at high altitude. Development of Mace "B" missiles began in 1954. The Mace "A" and Mace "B" were identical in all dimensions, but the Mace "B" (designated TM-76B) included a jam-proof inertial guidance system (designated TM-76B) and had a flight range exceeding 1,300 miles. The Mace missiles were deployed in Germany and on Okinawa until 1969, at which time the weapons system was retired, being replaced by Pershing missiles in Europe, and later, Gryphon cruise missiles.