W54 Special Atomic Demolition Munition (SADM) (2024)

Special Atomic Demolition Munition (SADM)

In the 1950s and 1960s, the U.S. developed lightweight nuclear devices to use in the interest of U.S. national security. Atomic Demolition Munition (ADM) first entered the Army’s nuclear arsenal in 1954, and one of the first tests of an ADM occurred in 1955 during Operation TEAPOT in Nevada. Intended to be used as engineering tools to deny an enemy access to specific areas or avenues of approach or to destroy enemy fortifications, ADMs were designed for use by small teams of engineers or special operations forces.The smallest ADM, known as the Special Atomic Demolition Munition (SADM), weighed approximately 150 pounds and used the 59-pound W-54warhead. The Special Atomic Demolition Munition (SADM) was a Navy and Marines project that was demonstrated as feasible in the mid-to-late 1960s, but was never used. This warhead’s two-man emplacement team could select from a range of explosive yields progressing from tens of tons to a thousand tons equivalent of TNT.

The project, which involved a small nuclear weapon, was designed to allow one individual to parachute from any type of aircraft carrying the weapon package that would be placed in a harbor or other strategic location that could be accessed from the sea. Another parachutist without a weapon package would follow the first parachutist to provide support as needed. The two-man team would place the weapon package in an acceptable location, set the timer, and swim out into the ocean where they would be retrieved by a submarine or other high-speed water craft. The parachute jumps and the retrieval procedures were practiced extensively. While the procedures were practiced extensively, SADM was never used.

Eventually, Army leaders grew skeptical about the practicality of employing ADMs. In 1987, after considering how quickly U.S. forces would need to use ADMs near the demilitarized zone (DMZ) in Korea to prevent them from falling into enemy hands in the event of a North Korean invasion, General Louis Menetrey, the U.S. commander there, said that keeping ADMs near the DMZ was “pretty dumb.” A similar recognition occurred in Europe, where Army planners came to realize that, in the event of an attack by the Warsaw Pact, ADMs would need to be employed in Allied territory at the beginning of a conflict if they were to be used at all.274 Major General William F. Burns (Ret.) noted, “As this realization sank in, such weapons were quietly retired.” These types of weapons are no longer in the stockpile.

Davy Crockett

The Davy Crockett consisted of an XM-388 projectile launched from either a 120-millimeter (XM-28) or 155-millimeter (XM-29) recoilless rifle (the 120 millimeter version is shown above). This weapon had a maximum range of 1.24 miles (120 millimeter) to 2.49 miles (155 millimeter). The XM-388 casing (including the warhead and fin assembly) weighed 76 pounds, was 30 inches long and measured 11 inches in diameter (at its widest point).

The M388 Davy Crockett was one of the smallest nuclear weapons developed in the 1950s, and fielded for use against Soviet troops. The M388 munition used a version of a very small subkiloton device. The Davy Crockett could be launched from two types of launchers: the M28, with a range a little over 1 mile (2 km), or M29, with a range of 2.5 miles (4 km). Both weapons used the same projectile, and could be mounted on a tripod launcher or carried by truck or armored personnel carrier, operated by a three-man crew.

Production of the Davy Crockett began in 1956, and deployed with U.S. Army forces from 1961 to 1971. Versions of the W54 warhead were also used in the AIM-26A Falcon. The W54 warhead used on the Davy Crockett weighed just 51 pounds and was the smallest and lightest fission bomb (implosion type) ever deployed by the United States, with a variable explosive yield of 0.01 kilotons (equivalent to 10 tons of TNT, or two to four times as powerful as the ammonium nitrate bomb which destroyed the Alfred P. Murrah federal building in Oklahoma City on April 19, 1995), or 0.02 kilotons-1 kiloton. A 58.6 pound variant — the B54 — was used in the Special Atomic Demolition Munition (SADM), a nuclear land mine deployed in Europe, South Korea, Guam, and the United States from 1964-1989.

The Davy Crockett was developed to give U.S. Army units an effective nuclear capability against potentially larger units of Soviet armored forces. The Davy Crockett was designed in the late 1950's primarily for frontline use by the U.S. infantry in Europe against Soviet troop formations. The Davy Crockett, a recoilless launcher, was the third artillery piece deployed, those earlier being a l55mm piece designed to fire a nuclear round and a 280mm mobile piece, commonly called an "atomic cannon." Nuclear-capable ground artillery pieces were gradually replaced by increasingly accurate, nuclear carrying missiles and aircraft.

The weapon system used a spin-stabilized, unguided rocket fired from a recoilless rifle. It's 51-pound nuclear warhead had an explosive yield of 0.18 kilotons (equivalent to 18 tons of TNT, with an added radiation effect). As a secondary design feature, the system could also fire a conventional high-explosive round for other use, such as an anti-tank weapon.

The Davy Crockett's warhead was launched from either a 120-millimeter (M-28) or 155-millimeter (M-29) recoilless rifle. The 155 millimeter version, which became the standard issue, had a maximum range of 2.49 miles and could be fired from either a ground tripod mount or from a specially designed jeep mount. The system was deployed with U.S. Army from 1961 to 1971, and over 2,100 were produced.

The heavy version was transported by either an armored personnel carrier or a large truck. The light version was generally carried on and fired from an Army jeep, but could be carried for a short distance and fired by a 3-man team. The W-54 nuclear warhead in a projectile was launched by the Davy Crockett and had a subkiloton yield. The projectile was 30 inches long, 11 inches in diameter, and weighed 76 pounds. The l55 mm launcher had a maximum range of 13,000 feet, and the 120 mm could reach a distance of 6,561 feet.

The W54 nuclear warhead was designed at the Los Alamos Scientific Laboratory (now the Los Alamos National Laboratory) and built by the Atomic Energy Commission. Successful test-firings of the warhead took place on July 7 and 17, 1962, at the Nevada Test Site in what were called the "Little Feller" shots. The July 17 test (using the 155 millimeter Davy Crockett) was conducted under simulated battlefield maneuvers and detonated 20 feet above ground at a distance of 1.7 miles, as planned.

Three Little Feller shots were originally considered. One was to he three feet above ground and the second 40 feet above ground. The third was to be launched tactically after having heen set to fire at a height of 40 feet. A military exercise was scheduled for this third shot. As plans developed, the third shot was canceled, and the second shot, which became LITTLE FELLER I, was changed to a three-foot shot to be launched in connection with a tactical maneuver.

Shot LITTLE FELLER II was detonated on 7 Julv 1962 at 1200 hours Pacific Daylight Time in Area 18* of the Nevada Test Site, UTM coordinates 619081. Sponsored by the Department of Defense, the test involved the detonation of a stockpile DAVY CROCKETT warhead intended as a companion shot for LITTLE FELLER I. The device, positioned three feet above the ground by a cable suspended between two posts, detonated with a low yield.

Sponsored by the Department of Defense, LITTLE FELLER I was a stockpile DAVY CROCKETT tactical weapon, similar to Shot LITTLE FELLER II. Army personnel fired the device as part of IVY FLATS, the troop exercise conducted after the detonation.

The Weapons Effects Test Group projects conducted at Shot LITTLE FELLER I were similar to those conducted at Shot LITTLE FELLER II but less extensive since the main objective of the shot was to test the DAVY CROCKETT weapons system and to stage the tactical exercise. The projects that were conducted were designed to provide data on the blast, shock, prompt nuclear radiation, and fallout effects of a low-yield nuclear detonation. Participants in these activities spent several weeks before the detonation placing and calibrating various types of instruments and gauges in the shot area. Project personnel accompanied by radiological safety monitors reentered the shot area at various times after the officially declared reentry hour to retrieve instruments and analyze data.

Exercise IVY FLATS, with approximately 1,000 participating soldiers, involved more DOD personnel than any other Nevada Test Site Organization project conducted at Shot LITTLE FELLER I. Exercise IVY FLATS was based on the following scenario. The United States was engaged in a war in which tactical nuclear weapons had been used. As part of a general offensive, a mechanized infantry battalion was given the mission of protecting the division right flank by seizing Objective 1.

The battalion commander was allocated DAVY CROCKETT weapons, one of which was the nuclear warhead and the others high-explosive weapons, which were to simulate nuclear weapons. Company A of the battalion had priority of fire from a battery of 105mm howitzers. The company was also supported by a platoon of tanks and mortars. The maneuver, to be conducted shortly after the LITTLE FELLER I detonation, was designed so that soon after the attack was launched, an enemy threat to the right flank was to be discovered. The battalion commander would then use two high-explosive weapons (simulated nuclear weapons) to neutralize this threat. Upon seizing Objective 1 and neutralizing the threat to the right flank, the exercise was to end.

This test, the last atmospheric detonation at the Nevada Test Site, was observed by Attorney General Robert F. Kennedy and presidential adviser General Maxwell D. Taylor. Footage of Operation IVY FLATS was declassified by the Department of Energy on December 22, 1997.

By 1965, nearly 400 warheads had been produced for the Davy Crockett system. As with ADMs, Davy Crockett weapons were deployed to countries throughout the world. By 1971, however, the Davy Crockett was withdrawn from service after commanders serving in Europe had criticized the weapon system, and after practice firings of the Davy Crockett had revealed that the weapons were inaccurate.

Improvement in overall safety and security was the objective of two 1979 US Army study programs relating to Atomic Demolition Munitions (ADM?s). The first, to be carried out jointly by the Department of Defense and the Department of Energy, assessed feasible alternatives pertinent to modernizing the Medium Atomic Demolition Munition (MADM). The second, also jointly sponsored, was concerned with the cost and feasibility of modernizing the Special Atomic Demolition Munition (SADM).

Special Atomic Demolition Mines (SADMs) were developed for employment by Soviet special operations forces, known as Spetsnaz. While the numbers of SADMs developed for possible use by Soviet forces was unclear, former Red Army intelligence personnel have written that these weapons were designed to have between a 0.8 and 2.0 kiloton yield, and were man-portable. Research suggested that the Soviets investigated applying "boosted fission" technology to their SADMs, which would provide 98% of the yield of fusion weapons.