W54 The W54 was one of the smallest nuclear warhead s deployed by the United States . It was a very compact implosion - type nuclear weapon design , designed for tactical use and had a very low yield for a nuclear weapon . Development . The W54 was designed by Los Alamos Scientific Laboratory and built by the United States Atomic Energy Commission . Around 400 units were manufactured from 1961 until early 1962 , and they were deployed until at least 1971 . Preproduction testing . The earliest identified nuclear tests of devices corresponding to the W54 characteristics were the Pascal - A and Pascal - B test detonations in 1957 , in the Operation Plumbbob nuclear test series . These were both intended to be very low yield , but overshot to higher yields ( tens and hundreds of tons ) . These were followed by tests of the XW - 51 design which evolved into the XW - 54 in the Operation Hardtack I test series in 1958 ( Hardtack " Quince " and Hardtack " Fig " ) . These were both described as fizzle s , or test failures . A number of XW - 51 / XW - 54 tests followed in the 1958 Operation Hardtack II test series , including Hardtack II Otero , Bernalillo , Luna , Mora , Colfax , Lea , Hamilton , Dona Ana , San Juan , Socorro , Catron , De Baca , Chavez , Humboldt , and Santa Fe . By this time , the XW - 51 / XW - 54 design had been test fired more times than any preceding US nuclear weapon prior to its successful introduction in service , indicating the difficulty of successfully making this small and low yield design work reliably and safely . Further testing followed in the 1961 Operation Nougat test series , probably including Nougat Shrew , Boomer , Ringtail , and possibly others . By this time the W - 54 design was performing consistently as expected at low yields . Variants . There were four distinct models of the basic W54 design used , each with different yield , but the same basic design . These were : Specifications . All four variants share the same basic core : a nuclear system which is 10 . 75 inches diameter ( 270 mm ) , about 15 . 7 inches long ( 400 mm ) , and weighs around or slightly over 50 pounds ( 23 kg ) . The W54 core , based on the available photos ( particularly of the Davy Crockett ) was neither spherical nor elliptical . The best interpolated photographic match to its external dimensions is a center cylindrical section 11 inches in diameter and 5 inches long , with roughly 5 . 5 inch radius hemispherical ends . Known and theoretical uses . These small size devices were first intended for use by United States Army ground soldiers in battle , and were in theory small enough to be delivered by a bazooka - style firing mechanism . Early known versions could destroy a two block area , with an estimated yield comparable to approximately 10 tons of TNT . Larger versions were later developed with a selectable yield of between 10 and 250 tons . Though small compared to most other nuclear weapons , whose yields are usually measured in the thousands of tons of TNT ( kilotons ) , in human terms they are still extremely large – a human might carry on his back 50 kg of chemical explosives , or 0 . 05 tons . By comparison , the smallest yield version of the W54 ( 10 tons ) is two to four times as powerful as the 1995 Oklahoma City bombing , making the 250 ton version 50 to 100 times as powerful . Several variations of the W54 are known to exist and they were used in weapons projects by every branch of the U . S . armed forces except the Coast Guard . The W54 style warhead was known to be used on the M - 388 Davy Crockett , a tactical nuclear recoilless rifle projectile that was deployed by the United States during the Cold War . The W54 is small enough to be deployed as a SADM ( Special Atomic Demolition Munition ) or so called " Backpack Nuke " . It was the closest thing the U . S . is known to have developed to a so - called " suitcase bomb " . The W54 was tested for use in a U . S . Navy SEAL project that was demonstrated as feasible in the mid - to - late 1960s , designed to attack a harbor or other strategic location that could be accessed from the sea . The SEAL version would be delivered into water by parachute along with a two man team , then floated to the target , set in place and armed by hand . The United States Air Force also developed a project using the W54 , the Hughes Electronics AIM - 26 Falcon . This was a larger , more powerful version of the AIM - 4 Falcon air - to - air missile . It is notable for being the only U . S . guided air - to - air weapon with a nuclear warhead . It was intended to destroy formations of Soviet bombers at a time when guided missiles were not accurate enough to produce high - probability kills with small conventional warheads . W72 . After the AIM - 26 Falcon was retired , 300 units were rebuilt into an improved configuration with a higher yield and redesignated the W72 . These warheads were then used to produce a number of nuclear versions of the AGM - 62 Walleye television guided glide bomb system . The W72 variant had a yield of around 600 tons of TNT . The 300 W72 units were produced between 1970 and 1972 , and were in service until 1979 . Documented testing . Stockpiled W54 warheads were test fired at the Nevada Test Site on July 7 and July 17 , 1962 . In Little Feller II ( July 7 ) , the warhead was suspended three feet above the ground and had a yield equivalent to 22 tons of TNT . In Little Feller I ( July 17 ) , the warhead was launched as a Davy Crockett device from a stationary 155 millimeter launcher and set to detonate between 20 and 40 feet above the ground around 1 . 7 miles from the launch point , with a yield of 18 tons . This test was the last atmospheric test at Nevada Test Site and was performed in conjunction with Operation IVY FLATS , a simulated military environment , and was observed by Attorney General Robert F . Kennedy and presidential adviser General Maxwell D . Taylor . Footage of Operation IVY FLATS was declassified by the United States Department of Energy on December 22 , 1997 . Limited operational details of early SADM projects were published prior to this declassification .