M55 rocket
Encyclopedia
The M55 rocket was a chemical weapon developed by the United States
in the 1950s. The United States Army produced both Sarin and VX unitary warheads for the M55.
. The Army produced unitary warheads filled with Sarin
(GB) and VX
nerve agent
s for the M55.
During the 1960s the Army stored many M55s at Black Hills Army Depot. The M55 was also stored at the Rocky Mountain Arsenal
and in Okinawa, Japan
. The rockets in Japan were moved to Johnston Atoll
during Operation Red Hat
where they were destroyed during the 1990s.
(NC) propellant. Besides the NG and NC, M28 contains 2-nitrodiphenylamine
(NDPA) as a stabilizer. The rocket propellant cannot be removed from the warhead without cutting open the rocket.
The propellant itself presents a hazard, because it becomes unstable as it ages. Specifically, the danger of autoignition is present as the stabilizer ages and becomes depleted. The U.S. National Research Council and other sources called the M55 the most dangerous weapon in the American chemical arsenal because of this and other hazards.
Another danger is agent leakage. Army reports have indicated that nerve agent GB can corrode the metal casings of the munitions over time. As Sarin decomposes it forms acids which can corrode the aluminum casings found around the agent in the M55. M55 rockets containing GB have accounted for the majority of leaking American chemical weapons. In mid-2002, over 4,000 munitions in the U.S. chemical stockpile were found to be leaking agent; of that number 2,102 were Sarin containing M55s.
s filled with about 10 pounds of GB or VX. The warhead comprises about 15 pounds total, and consists of several components. The M34 and M36 Burster utilize composition B
or tetrytol
and total about 3 pounds of the total weapon weight. The agent, as stated, comprises about ten pounds of the weight with the rest lying in the casing and M417 fuse.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in the 1950s. The United States Army produced both Sarin and VX unitary warheads for the M55.
History
In 1951 the US Army Chemical Corps and Ordnance Corps initiated a joint program to develop a 115mm chemical rocket. The US Army Ordnance Corps designed the 115mm T238 and launcher in 1957 to provide the army a means to attack large area targets with chemical agents. Artillery and mortars are for small area targets; and due to different spin stabilities weapons intended for explosives are not ideal for chemical delivery. The 115mm rocket was subsequently accepted as the M55 rocket with M91 launcher. Produced from 1959–1965, the M55s were manufactured at Newport Army Ammunition Plant and tested at Aberdeen Proving GroundAberdeen Proving Ground
Aberdeen Proving Ground is a United States Army facility located near Aberdeen, Maryland, . Part of the facility is a census-designated place , which had a population of 3,116 at the 2000 census.- History :...
. The Army produced unitary warheads filled with Sarin
Sarin
Sarin, or GB, is an organophosphorus compound with the formula [2CHO]CH3PF. It is a colorless, odorless liquid, which is used as a chemical weapon. It has been classified as a weapon of mass destruction in UN Resolution 687...
(GB) and VX
VX (nerve agent)
VX, IUPAC name O-ethyl S-[2-ethyl] methylphosphonothioate, is an extremely toxic substance whose only application is in chemical warfare as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations in UN Resolution 687...
nerve agent
Nerve agent
Nerve agents are a class of phosphorus-containing organic chemicals that disrupt the mechanism by which nerves transfer messages to organs...
s for the M55.
Storage
Rocky Mountain Arsenal
The Rocky Mountain Arsenal was a United States chemical weapons manufacturing center located in the Denver Metropolitan Area in Commerce City, Colorado...
and in Okinawa, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. The rockets in Japan were moved to Johnston Atoll
Johnston Atoll
Johnston Atoll is a atoll in the North Pacific Ocean about west of Hawaii. There are four islands located on the coral reef platform, two natural islands, Johnston Island and Sand Island, which have been expanded by coral dredging, as well as North Island and East Island , an additional two...
during Operation Red Hat
Operation Red Hat
Operation Red Hat was a U.S. military action taking place in 1971, which involved the movement of chemical warfare munitions from Okinawa, Japan to Johnston Atoll in the North Pacific Ocean.-Operation:...
where they were destroyed during the 1990s.
Disposal issues
Disposal operations for the M55 are made more difficult because of the rocket's design. The rocket propellant was a double base composition nitroglycerin (NG) and nitrocelluloseNitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
(NC) propellant. Besides the NG and NC, M28 contains 2-nitrodiphenylamine
2-Nitrodiphenylamine
2-Nitrodiphenylamine, also called NDPA, 2-NDPA, 2NO2DPA, Sudan Yellow 1339, C.I. 10335, CI 10335, phenyl 2-nitrophenylamine, 2-nitro-N-phenylaniline, or N-phenyl-o-nitroaniline, is an organic chemical, a nitrated aromatic amine, a derivate of diphenylamine. Its chemical formula is C12H10N2O2, or...
(NDPA) as a stabilizer. The rocket propellant cannot be removed from the warhead without cutting open the rocket.
The propellant itself presents a hazard, because it becomes unstable as it ages. Specifically, the danger of autoignition is present as the stabilizer ages and becomes depleted. The U.S. National Research Council and other sources called the M55 the most dangerous weapon in the American chemical arsenal because of this and other hazards.
Another danger is agent leakage. Army reports have indicated that nerve agent GB can corrode the metal casings of the munitions over time. As Sarin decomposes it forms acids which can corrode the aluminum casings found around the agent in the M55. M55 rockets containing GB have accounted for the majority of leaking American chemical weapons. In mid-2002, over 4,000 munitions in the U.S. chemical stockpile were found to be leaking agent; of that number 2,102 were Sarin containing M55s.
Specifications
The M55 is 78 inches long and 4.44 inches in diameter. The 57 pound weapons can hold warheadWarhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
s filled with about 10 pounds of GB or VX. The warhead comprises about 15 pounds total, and consists of several components. The M34 and M36 Burster utilize composition B
Composition B
Composition B, colloquially "comp B", is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades, sticky bombs and various other munitions...
or tetrytol
Tetrytol
Tetrytol is a high explosive, comprising a mixture of Tetryl and TNT. Typically, the proportion of ingredients is approximately 70% tetryl and 30% TNT...
and total about 3 pounds of the total weapon weight. The agent, as stated, comprises about ten pounds of the weight with the rest lying in the casing and M417 fuse.
See also
- Binary chemical weapons
- Anniston Chemical ActivityAnniston Chemical ActivityAnniston Chemical Activity is a U.S. Army chemical weapon storage site located in Alabama. The Army had stored approximately seven percent of the nation’s original chemical weapons stockpile at the Anniston Army Depot since the early 1960s. In August 2003, the Army began disposing of these weapons...
- Johnston Atoll Chemical Agent Disposal SystemJohnston Atoll Chemical Agent Disposal SystemJohnston Atoll Chemical Agent Disposal System was the U.S. Army's first chemical munitions disposal facility. It was located on Johnston Island, at Johnston Atoll and completed its mission and ceased operation in 2000.-Background:...
- List of U.S. Army Rocket Launchers By Model Number (M91)
Further reading
- Puro, Toivo E. Nerve Gas, (Google Books), Trafford Publishing, 2006, p. 112, (ISBN 1412072964).