AJ-60A is a

solid rocket booster A solid rocket booster (SRB) is a solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and Space Shuttle, have used SRBs to give laun ...

produced by

Aerojet Rocketdyne Aerojet Rocketdyne is a subsidiary of American Arms industry, defense company L3Harris that manufactures rocket, Hypersonic flight, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Aerojet traces ...

. Up to 2020 they were used as strap-on boosters on all

United Launch Alliance United Launch Alliance, LLC (ULA) is an American launch service provider formed in December 2006 as a joint venture between Lockheed Martin Space and Boeing Defense, Space & Security. The company designs, assembles, sells and launches rockets ...

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas (rocket family), Atlas launch vehicle family. It was developed by Lockheed Martin and has been operated by United Launch Alliance (ULA) since 2006. Primarily used to ...

rocket configurations. They continue to be used on the Atlas V N22 configuration used to launch the

Boeing Starliner The Boeing Starliner (or CST-100) is a spacecraft designed to transport crew to and from the International Space Station (ISS) and other low-Earth-orbit destinations. Developed by Boeing under NASA's Commercial Crew Program (CCP), it consists o ...

History

The AJ-60A rocket motor was developed between 1999 and 2003 for use on the Atlas V. On January 19, 2006 the

New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...

spacecraft to Pluto was launched directly into a solar-escape trajectory at from Cape Canaveral using an Atlas V version with 5 of these SRBs and Star 48B third stage. ''New Horizons'' passed the Moon's orbit in just nine hours. In 2015, ULA announced that the Atlas V will switch to new GEM 63 boosters produced by

Northrop Grumman Innovation Systems Orbital ATK Inc. was an American aerospace manufacturer and defense industry company. It was formed in February 9, 2015 from the merger of Orbital Sciences Corporation and parts of Alliant Techsystems (ATK). Orbital ATK designed, built, and deli ...

. (GEM 63XL, a stretched version of the GEM 63 booster is used on the Vulcan rocket.) The first

launched with GEM 63 boosters on November 13, 2020.''Northrop Grumman Ships GEM 63 Engines to United Launch Alliance For Atlas V'' July 2020
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Design

AJ-60A is a solid fueled rocket burning

HTPB Hydroxyl-terminated polybutadiene (HTPB) is an oligomer of butadiene terminated at each end with a hydroxyl functional group. It reacts with isocyanates to form polyurethane polymers. HTPB is a translucent liquid with a color similar to wax paper ...

-based composite solid propellant. The casing is composed of a

graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...

epoxy Epoxy is the family of basic components or Curing (chemistry), cured end products of epoxy Resin, resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide fun ...

composite, and the engine throat and nozzle are made of

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

- phenolic composite. As configured for use on Atlas V, the nozzle is fixed at a 3 degree cant away from the attachment point, but Aerojet offers a variant with thrust vectoring capability. The Atlas V configuration also features an inward slanting nosecone, but it is available with a conventional nosecone or none at all for use on other rockets. The stages are designed to be transported by truck.

References

{{Rocket engines Rocketdyne engines Solid-fuel rockets Rocket engines of the United States