Solid Fuel Rocket Boosters

Minuteman Missile Rocket Booster Stages Schematic

Minuteman Solid Fuel Rocket Boosters

Minuteman Solid Fuel Rocket Boosters

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The Minuteman missile has a total of 3 solid fuel rocket boosters. Each booster stage is manufactured by a different company. The first stage booster is manufactured by Thiokol. The second stage is manufactured by Aerojet, and the third stage booster is manufactured by the Hercules Powder Company.

In order to provide a better understanding of the location and layout of the 3 separate solid fuel rocket boosters, view the image above

Minuteman III First Stage Booster

Minuteman III First Stage Rocket Booster

With the Minuteman I missile, the first stage rocket booster, manufactured by Thiokol, weighed a total of 51,251 pounds. The motor case material was made of D6AC steel. This first stage was 18.6 feet long and 5.5 feet in diameter. The weight of the propellant itself was 45,670 pounds. The Thiokol solid rocket booster produced a total of 200,400 pounds of thrust

Thiokol came about when two chemists, Joseph C Patrick and Nathan Mnookin, were trying to invent an inexpensive antifreeze back in 1926. What they ended up creating was a gum of which its substance caused a significant clog in the laboratory sink, and also had the characteristic of having an awful odor. None of the industrial strength solvents they used would clear the clog in the sink.

The two frustrated chemists came to the conclusion that the resistance of the material, Thiokol, possessed a useful property. What they came to realize is that they created a synthetic rubber, which would later be used in the manufacture of a solid fuel rocket booster. "Thiokol" comes from the Greek words sulphur and glue.

In 1945 a gentleman by the name of Charles Bartley, who was working for the Jet Propulsion Laboratory, discovered that the properties of thiokol can be used as a stabilizer in solid fueled rockets. In 1958 Thiokol was awarded the contract to build the first stage solid rocket booster for the Minuteman I missile.

The solid propellant fuel that is used in the first three stages of both the Minuteman II and III missiles, (including the Peacekeeper) relies on acrylic acid/aluminum powder for fuel, combined with ammonium perchlorate as the oxidizer, and polybutadiene as the binder. Once the booster is ignited, the solid propellant cannot be extinguished; it burns until it is depleted.

Second Stage Rocket Booster

Minuteman III Second Stage Rocket Booster

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For the Minuteman I missile the second stage booster was manufactured by Aerojet.

The second stage solid fuel rocket booster manufactured by Aerojet used titanium as its motor case material. Its total weight is 12,072 pounds, and the propellant alone weighs 10,380 pounds. The second stage booster has a length of 9.1 feet and a diameter of 3.7 feet. The maximum thrust for this booster is 45,600 pounds.

Second Stage Rocket Booster

Minuteman III Second Stage Booster

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Minuteman III Third Stage Booster

Minuteman III Third Stage Booster

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On the Minuteman I missile, the third stage booster was manufactured by the Hercules Powder Company. The motor case material used for this booster was made from S-901 fiberglass. Total weight of this booster was 4,484 pounds and the propellant alone weighed 3,668 pounds. The third stage booster has a length of 5.1 feet and a diameter of 3.1 feet. The maximum thrust of the 3rd stage booster is 17,100 pounds.

Minuteman III Third Stage Booster Being Tested

Minuteman III Third Stage Booster Being Tested

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Minuteman II and Minuteman III Solid Fuel Rocket Boosters

Second Stage Booster

Some characteristics of the first, second and third stage boosters varied with the improvements made with the Minuteman II and III missiles. The first stage booster, manufactured by Thiokol, remained the same with the Minuteman I, II and III missile. There were no changes in the weight of the booster, the fuel used, or the maximum thrust this booster was capable of producing.

The Aeroject manufactured second stage booster changed with the Minuteman II missile. Its total weight increased to 16,057 pounds, and the propellant alone weighed 13,680. The motor case material used an improved 6AL-4V titanium. The type of propellant used with this booster was a newer improved propellant. The length of this booster remained the same (9.1 feet) and its diameter increased to 4.3 feet.

The second stage booster for the Minuteman II missile saw an increase in maximum thrust of an additional 15,100 pounds. The maximum thrust with this booster produced 60,700 pounds of thrust compared to its 45,600 pounds of thrust with the Minuteman I. The Aerojet booster remained virtually the same with the Minuteman III missile, except for having a drop of 18 pounds in total weight of its booster, dropping from 16,057 pounds to a total weight of 16,039 pounds.

Third Stage Booster

The Hercules Powder Company manufactured third stage booster carried on with the Minuteman II missile, and had essentially the same specifications as the booster used with the Minuteman I missile. With the introduction of the Minuteman III missile, the third stage rocket booster used on this missile was manufactured by the CSD company, which is Pratt and Whitney's solid rocket company.

The CSD manufactured third stage booster retained the same motor case material of S-901 fiberglass. The total weight of the booster increased almost two fold, from a total weight of 4443 pounds to 8187. The weight of the propellant fuel alone increased from 3668 pounds to 7292 pounds. This specific booster has a length of 5.5 feet and a diameter of 4.3 feet. Its maximum thrust doubled with the Minuteman III missile. With the Minuteman II missile the maximum thrust was 17,100 pounds. With the Minuteman III missile the CSD third stage booster produces a maximum thrust of 34,500 pounds.