Directory of U.S. Military Rockets and Missiles
Copyright © 2002 Andreas Parsch

Emerson Electric M47/M51/MGR-3 Little John

The Little John was the smallest nuclear-capable rocket the U.S. Army ever deployed. Studies to develop a lightweight rocket based on the M31/MGR-1 Honest John to give airborne Army units a nuclear capability began in 1953 under the name Honest John Junior. After preliminary studies by Douglas during 1954, the development program - renamed as Little John - was officially started at Redstone Arsenal in June 1955. In June 1956, the first launch of the XM47 Little John occurred. The XM47 was only an interim rocket, essentially a rocket test vehicle, and was used for training and testing purposes only.

Photo: U.S. Army

Development of the final tactical Little John, then known as XM51, began in 1956, and test firings were conducted between December 1958 and October 1959. Production of the XM51 rocket began in late 1959, and the first rockets were deployed by airborne battalions in January 1961. In September 1961 the XM51 Little John was reclassified as M51.

The M51 Little John was an air-transportable, unguided artillery rocket powered by an XM26 solid-fuel rocket motor, and armed with a nuclear or conventional warhead. The M51 was delivered fully assembled to the firing units, either by helicopter, or already mounted on its M34 towed launcher. Once the launch site was reached, the Little John was ready for aiming and firing.

Photo: U.S. Army
XM51 (MGR-3A)

In 1963, when production was already completed (all by Emerson Electric), the M51 was redesignated as MGR-3A. Little John production and deployment was limited, because it was designed mainly for airborne operations, and there were only two airborne Army units at the time. In August 1969, the MGR-3A was withdrawn from service. There was no official reason for this early retirement, but it's possible that the rocket was considered redundant after the M454 155mm nuclear projectile had been fielded in 1964.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for MGR-3A:

Length4.41 m (14 ft 5.7 in)
Finspan0.60 m (1 ft 11.75 in)
Diameter0.32 m (12.5 in)
Weight353 kg (779 lb)
SpeedMach 1.5
Range18.2 km (11.3 miles)
PropulsionHercules XM26 solid-fueled rocket motor
WarheadW-45 nuclear fission (1-10 kT); or conventional HE

Main Sources

[1] James N. Gibson: "Nuclear Weapons of the United States", Schiffer Publishing Ltd, 1996
[2] Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
[3] Redstone Arsenal Historical Information Website

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Last Updated: 6 January 2002