In October 1943, Chance Vought signed a study contract for a 300-mile range pilotless missile that carried a 4,000-pound warhead. But little transpired until the soon-to-be-separated AAF provided the impetus for the Navy Program. In May 1947, the Army airmen awarded Martin a contract for a turbojet-powered subsonic missile which became the Matador. The Navy saw this as a threat to its role in guided missiles and, within days, ordered BuAer to start a similar Navy missile that could be launched from a submarine, using the same engine as the Matador (J33) and components on hand. By August 1947, the project had gained both a name (Regulus) and performance requirements. The Navy wanted the missile to carry a 3,000-pound warhead to a maximum range of 500 nm at Mach .85 with a CEP of .5 percent of the range. The vehicle would be 30 feet in length, 10 feet in span, 4 feet in diameter, and would weigh between 10,000 and 12,000 pounds.
Another factor fostering the development of the Regulus program, and which became increasingly important, was the Navy's desire to deliver a nuclear weapon. The Navy's problem centered on the heavy weight of atomic weapons in the late 1940s (about five tons), just too heavy for almost all carrier-launched aircraft. The Navy converted twelve P2Vs (twin-propeller-powered patrol bombers) for such a role, but while they could take off from carrier decks, they could not land on them. Only the AJ Savage could do both. The Navy converted the North American bombers for nuclear delivery, but they were limited in range to about 800 miles. Captain Fahrney, of World War II drone fame, proposed a pilotless version of the Al with a range of about 1,400 nm. But the Navy canceled this TAURUS project in 1948. So despite mechanical and tactical limitations, the AJ represented the only carrier aircraft capable of delivering a nuclear weapon in the early 1950s. New urgency to develop nuclear delivery systems followed the Soviet nuclear test in the summer of 1949. Therefore, the Military Liaison Committee to the Atomic Energy Commission recommended consideration of Regulus along with three other missiles for this role.
Certainly interservice competition complicated the missile's development. Navy's Regulus and USAF's Matador not only looked alike; their performance, schedule, and costs were about the same, and they used the same engine. With pressure to reduce defense spending in 1949, the Department of Defense (DOD) impounded fiscal 1950 funds for both missiles. Because most observers considered Matador to be about a year ahead of the Regulus, DOD ordered the Air Force to determine if Matador would indeed work, and BuAer to slow development of Regulus and fund a study to determine if Matador could be adapted for Navy use. But the Navy successfully argued that Regulus could perform the Navy mission better than could Matador. Regulus advocates pointed to its simpler guidance system which required only two stations (submarines) while the Matador required three. Also, the Matador's single booster had to be fitted to the missile after it was on the launcher while, in contrast, the Regulus was stowed with its two boosters attached. This meant that in comparison to the Regulus, the Matador would require more men and machinery and that the submarine had to remain on the surface longer, thereby increasing its vulnerability to enemy action. In addition, Chance Vought built a recoverable version of the missile, which meant that while each Regulus test vehicle cost more than the Martin missile to build, Regulus was cheaper to use than Matador over the series of tests. While some of the Matador's problems would doubtlessly have been resolved, the Navy insisted on a separate program; and in June 1950, the joint service Research and Development Board concurred. The Navy program continued.
Two 33,000-pound-thrust boosters launched Regulus, which first flew in March 1951. The first submarine launch of Regulus occurred in July 1953 from the deck of the USS Tunny. After such a launch, the Navy guided the Regulus toward its target by two other submarines and, later, with the Trounce system, one submarine. Regulus could also be launched from surface ships. Cruisermen were enthusiastic about this weapon which would extend both their offensive range and mission. The lack of a capability to pass control of the missile from the cruisers and submarines, however, limited the weapon. The Navy also launched the missile from carriers and guided it with a control aircraft. Problems included booster launch (the launcher weighed eleven tons and sometimes spectacularly malfunctioned), control aircraft (which lacked adequate speed and range to do the job), and the entire radio control system. Engineers resolved these problems but naval aviators, like their Air Force brethren, strongly preferred aircraft and this preference may well have undermined the Regulus program.
Nevertheless in 1955, Regulus became operational, eventually serving aboard diesel- and nuclear-powered submarines, cruisers, and aircraft carriers. The last versions of the missile could carry a 3.8 megaton warhead 575 miles at Mach .87. Regulus phased out of production in January 1959 with delivery of the 514th missile. The Navy launched perhaps 1,000, obviously including many of the recoverable versions, before it took Regulus out of service in August 1964. Admiral Zumwalt calls that decision the "single worst decision about weapons [the Navy] made during my years of service. " But careful examination of Regulus reveals few advantages over the V-l. While the Chance Vought flew somewhat further and faster, American guidance was not much better than the earlier German missile guidance system. The principal American missile improvements were the nuclear warhead and increased reliability.
By mid-1958, USS Grayback (SSG-574) and USS Growler (SSG-577) had been commissioned as the first purpose-built Regulus submarines, each carrying two in a large bow hangar. At that time, the Navy had four SSGs and four missile-carrying cruisers at sea. When USS GRAYBACK (SSG 574) slipped it moors and headed into the Pacific Ocean in September 1959, it began an era of submarine history that would go unrecognized for almost 40 years. The five REGULUS submarines, USS GRAYBACK (SSG 574), USS TUNNY (SSG 282), USS BARBERO (SSG 317), USS GROWLER (SSG 577) and USS HALIBUT (SSGN 687) deployed on 41 deterrent patrols under the earth's oceans over the course of 5 years.