AJ-60A is a

solid rocket booster A solid rocket booster (SRB) is a large 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 gi ...

produced by

Aerojet Rocketdyne Aerojet Rocketdyne is an American manufacturer of rocket, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Headquartered in Sacramento, California, the company is owned by Aerojet Rocketdyne Hold ...

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

United Launch Alliance United Launch Alliance (ULA), legally United Launch Alliance, LLC, is an American spacecraft launch service provider that manufactures and operates a number of rocket vehicles that are capable of launching spacecraft into orbits around Earth, a ...

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

rocket.

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 space probe that was launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institute (SwRI), with a ...

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 Northrop Grumman Innovation Systems (NGIS) was a sector (business segment) of Northrop Grumman from 2018 through 2019. It was formed from Orbital ATK Inc. a company which resulted from the merger of Orbital Sciences Corporation and parts of Alli ...

. (GEM 63XL, a stretched version of the GEM 63 booster will be used on the upcoming

Vulcan Vulcan may refer to: Mythology * Vulcan (mythology), the god of fire, volcanoes, metalworking, and the forge in Roman mythology Arts, entertainment and media Film and television * Vulcan (''Star Trek''), name of a fictional race and their home p ...

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
/ref>

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 ...

. The casing is composed of a

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...

epoxy Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also co ...

composite, and the engine throat and nozzle are made of

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...

- 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