SSM-N-8 Regulus

Test articles of the Regulus were equipped with landing gear and could take off and land like an airplane. When the missiles were deployed they were launched from a rail launcher, and equipped with a pair of Aerojet 2.2-KS-33,000 JATO bottles on the aft end of the fuselage.

• Is Missile — yes • Name — SSM-N-8 Regulus • Origin — United States • Type — Cruise missile • Used By — United States Navy • Manufacturer — Chance Vought • Production Date — March 1951 • Service — 1955-64 • Engine — Allison J33-A-14 turbojet 4600 lbf 2 × Aerojet 2.2-KS-33,000 booster rockets 33000 lbf apiece. • Weight — 13685 lb • Length — 32 ft • Diameter — 4 ft • Wingspan — 21 ft extended 9 ft folded • Speed — Subsonic • Vehicle Range — 500 nmi • Filling — 3000 lb such as the W5 warhead or the W27 warhead • Guidance — radio-command by ground stations, aircraft, or ships along the flight path

Nazi Germany's use of the V-1 flying bomb during World War II marked the first combat deployment of a cruise missile, highlighting the potential of a new class of weapon. Even before Germany's surrender, the United States captured, reverse-engineered, and mass-produced its own version of the V-1, the Republic-Ford JB-2 Loon, intended for use against Japan. With the war's end and the onset of the Cold War, the U.S. sought new ways to deploy nuclear warheads. One proposal, put forward by Captain Thomas Klakring, was to launch nuclear missiles from submarines. He argued that submarines would be far more difficult to detect and attack than surface ships, such as aircraft carriers, while also introducing a new method of warhead delivery beyond aircraft. At the time, bombers were the U.S. military's only means of delivering nuclear warheads, a reliance that threatened to diminish the Navy's role and overemphasize a single approach to nuclear strategy. Klakring proposed launching the Loon from submarines to test his concept. Work began in 1946, and by 1947, USS Cusk became the first U.S. submarine to fire a guided missile. Testing continued for several years, but significant issues arose. Cusk nearly sank when a Loon exploded on deck, and the missile itself was slow, had limited range and payload, and was impractical for military use. Despite these shortcomings, the tests successfully demonstrated how a submarine could surface, launch a missile, and submerge again, making it difficult for an enemy to retaliate. The Navy acknowledged the concept’s potential but recognized the need for a missile specifically designed for submarine deployment.

Development of such a missile began with Grumman's SSM-N-6 Rigel and the Johns Hopkins Applied Physics Laboratory's SSM-N-2 Triton. However, work did not begin in earnest until August of 1947, days after the United States Army Air Force awarded a contract for the ground-based MGM-1 Matador cruise missile. The Navy, not wanting to lose its edge in missile development, began Project Regulus with the same equipment used in the Matador. On 17 November 1947, a contract was awarded to Chance Vought, which previously investigated a similar project as part of a study on "pilotless missiles". The company, desperate for government contracts as the money-making F4U Corsair production line was nearing an end, focused on a practical design that could be brought into service quickly. With its survival at stake, the company invested heavily in research and development, drawing from experience with jet fighter projects such as the broadly similar F6U Pirate. The Navy initially planned on having each missile be operational in a sequential order, starting with the simple Regulus and ending with the more complex but capable Triton in 1960. However, both the Rigel and Triton were powered by ramjets, which presented a significant challenge as the technology was too immature for immediate use, eventually leading to both programs' cancellation.

The contract required the missile to have a range of 500 nmi at Mach 0.85, a 3000 lb warhead, and a circular error probable (margin of error) of 2.5 nmi. Regulus was designed to be 30 ft long, 10 ft in wingspan, 4 ft in diameter, and would weigh between 10000 and. The missile somewhat resembled the contemporary F-84 Thunderjet fighter aircraft, but without a cockpit, and test versions were equipped with landing gear so that they could be recovered and re-used. After launch, Regulus would be guided toward its target by control stations, typically by submarines or surface ships equipped with guidance equipment. It could also be flown remotely by chase aircraft. (Later, with the "Trounce" system (Tactical Radar Omnidirectional Underwater Navigational Control Equipment), one submarine could guide it). Army-Navy competition complicated both the Matador's and the Regulus' developments. The missiles looked alike and used the same engine. They had nearly identical performances, schedules, and costs. Under pressure to reduce defense spending, the United States Department of Defense ordered the Navy to determine if Matador could be adapted for their use. The Navy concluded that the Navy's Regulus could perform the Navy mission better. Regulus had some advantages over Matador. It required only two guidance stations while Matador required three. It could also be launched quicker, as Matador's boosters had to be fitted while the missile was on the launcher while Regulus was stowed with its boosters attached. Finally, Chance Vought built a recoverable version of the missile, designated KDU-1 and also used as a target drone, so that even though a Regulus test vehicle was more expensive to build, Regulus was cheaper to use over a series of tests. The Navy program continued, and the first Regulus flew in March 1951. Due to its size and regulations concerning oversize loads on highways, Chance Vought collaborated with a firm that specialized in trucking oversize loads to develop a special tractor trailer combination which could move a Regulus I missile.

• Illustration — Tunny launches a Regulus I in 1956. The first launch from a submarine occurred in July 1953 from the deck of Tunny, a World War II fleet boat modified to carry Regulus. Tunny and her sister boat Barbero were the United States's first nuclear deterrent patrol submarines. They were joined in 1958 by two purpose-built Regulus submarines, Grayback and Growler, and, later, by the nuclear-powered. Halibut, with its extremely large internal hangar could carry five missiles and was intended to be the prototype of a whole new class of cruise missile firing SSG-N submarines. The Navy strategy called for four Regulus missiles to be at sea at any given time. Thus, Barbero and Tunny, each of which carried two Regulus missiles, patrolled simultaneously. Growler and Grayback, with four missiles each, or Halibut, with five, could patrol alone. Operating from Pearl Harbor, Hawaii, the five Regulus submarines made 40 nuclear deterrent patrols in the Northern Pacific Ocean between October 1959 and July 1964, including during the Cuban Missile Crisis of 1962. According to the documentary "Regulus: The First Nuclear Missile Submarines" by Nick T. Spark, their primary task in the event of a nuclear exchange would be to eliminate the Soviet naval base at Petropavlovsk-Kamchatsky. These deterrent patrols represented the first by the Navy's submarines and preceded those made by the Polaris missile submarines. • Regulus submarines • Class — Name — In Commission — Number of missiles — Post-Regulus use • Gato — Tunny — 1953-1965 — 2 — Converted to amphibious transport submarine • Balao — Barbero — 1955-1964 — Expended as target 1964 • Grayback — Grayback — 1958-1964 — 4 — Converted to amphibious transport submarine • Growler — 1958-1964 — Decommissioned, memorial 1988 • Halibut — 1960-1964 — 5 — Converted to special mission submarine The Regulus firing submarines were relieved by the s carrying the Polaris missile system. Barbero also earned the distinction of launching the only delivery of missile mail. Additional submarines including USS Cusk and USS Carbonero were equipped with control systems that allowed them to take control of a Regulus in flight, thus extending its range in a tactical situation. Regulus was also deployed by the U.S. Navy in 1955 in the Pacific on board the cruiser Los Angeles. In 1956, three more followed: Macon, Toledo, and Helena. These four s each carried three Regulus missiles on operational patrols in the Western Pacific. Macon last Regulus patrol was in 1958, Toledo in 1959, Helena in 1960, and Los Angeles in 1961. • Illustration — A Regulus I fired from Los Angeles, 1957. Ten aircraft carriers were configured to operate Regulus missiles (though only six ever launched one). Princeton did not deploy with the missile but conducted the first launch of a Regulus from a warship. Saratoga also did not deploy but was involved in two demonstration launches. Franklin D. Roosevelt and Lexington each conducted one test launch. Randolph deployed to the Mediterranean carrying three Regulus missiles. Hancock deployed once to the Western Pacific with four missiles in 1955. Lexington, Hancock, Shangri-La, and Ticonderoga were involved in the development of the Regulus Assault Mission (RAM) concept. RAM converted the Regulus cruise missiles into an unmanned aerial vehicle (UAV): Regulus missiles would be launched from cruisers or submarines, and once in flight, guided to their targets by carrier-based pilots with remote control equipment.

A second generation supersonic Vought SSM-N-9 Regulus II cruise missile with a range of 1,200 NM and a speed of Mach 2 was developed and successfully tested, including a test launch from Grayback, but the program was canceled in favor of the UGM-27 Polaris nuclear ballistic missile. The Regulus II missile was a completely new design with improved guidance and double the range, and was intended to replace the Regulus I missile. Regulus II-equipped submarines and ships would have been fitted with the Ships Inertial Navigation System (SINS), allowing the missiles to be aligned accurately before take-off. Forty-eight test flights of Regulus II prototypes were carried out, 30 of which were successful, 14 partially successful and four failures. A production contract was signed in January 1958 and the only submarine launch was carried out from Grayback in September 1958. Due to the high cost of the Regulus II (approximately one million dollars each), budgetary pressure, and the emergence of the UGM-27 Polaris SLBM (submarine-launched ballistic missile), the Regulus II program was canceled on 18 December 1958. At the time of cancellation Vought had completed 20 Regulus II missiles with 27 more on the production line. Production of Regulus I missiles continued until January 1959 with delivery of the 514th missile, and it was withdrawn from service in August 1964. Both Regulus I and Regulus II were used as target drones after 1964.

The following museums in the United States have Regulus missiles on display as part of their collections: • Carolinas Aviation Museum, Charlotte, North Carolina • Regulus I missile in launch position at the Carolinas Aviation Museum in Charlotte, North Carolina. It is mounted on a catapult launching stand used for aircraft carrier launches and was restored late 2006 after having been on outdoor display for a number of years. • Frontiers of Flight Museum, Dallas Love Field, Texas • Regulus II missile • Intrepid Sea-Air-Space Museum, New York City, New York • Regulus I cruise missile can be seen ready for simulated launch on board Growler at the Intrepid Sea-Air-Space Museum in New York City. • Point Mugu Missile Park, Naval Air Station Point Mugu, California • The museum's collection includes both a Regulus and a Regulus II missile • Bowfin Museum, Pearl Harbor, Hawaii: • Veterans Memorial Museum, Huntsville, Alabama • Regulus II missile • Smithsonian Institution, National Air and Space Museum • Regulus I on display at Steven F. Udvar-Hazy Center • New Jersey Naval Museum, Hackensack, New Jersey • Regulus with intact engine • US Navy Pacific Missile Range Facility, Barking Sands, island of Kauai, Hawaii • Regulus I restored in 2011 on static display inside the North Gate

* • United States Navy (from 1955 to 1964)