Commercial Rocket Motors

Commercial Rocket Motors

Defining possible for national security, science and commercial missions.

Northrop Grumman’s commercial motor products build upon flight-proven heritage and leverage commonalities to continuously improve and expand motor families at a low-cost and with high reliability and repeatable performance.

A large rocket motor being tested at testing faciltiy


The CASTOR® rocket motor premiered as a second-stage motor to boost the Scout X-1 rocket for NASA in September 1960. Since then, Northrop Grumman has used the base technology from four generations of ballistic missile boosters and the technology and experience from expendable launch vehicle programs, to expand the CASTOR series. The family of motors has grown to include ten flight-ready first-and second-stage and strap-on solid rocket motors that serve space launch, sounding rockets and the missile defense targets market. CASTOR motor variations support Northrop Grumman Minotaur-C vehicles, and the latest generation CASTOR 30XL motor propels the upper stage of Antares for cargo resupply missions to the International Space Station.

two men in blue coats work on rocket

Orion Motors

The Orion product line began with three stages designed for Northrop Grumman’s Pegasus® and grew to support various Taurus®, Pegasus XL, and Minotaur® configurations, as well as the Ground-based Midcourse Defense (GMD) interceptor. New applications continue to evolve to support the Missile Defense Agency’s target vehicle configurations for the medium-range ballistic missile, intermediate-range ballistic missile, and intercontinental ballistic missile classes. The multiple configurations and applications of the Orion motor family demonstrate these flight-proven motors’ adaptability and reliability.

Engineers at the Magna, Utah, facility maneuver the single, 72-foot-long case into the casting pits.

Graphite Epoxy Motors (GEM)

Northrop Grumman began developing the Graphite Epoxy Motor (GEM) in the early 1980s with the GEM 40 to increase launch capability for the Delta II launch vehicle, followed by the GEM 46, used on the Delta III and Delta II Heavy, and GEM 60 for the Delta IV Medium-Plus vehicle. The fourth-generation GEM 63 booster flew its inaugural flight on the Atlas V in November 2020, and the company began testing the extended-length GEM 63XL variant, the longest monolithic rocket motor produced to date, in August 2020 to serve the Vulcan Centaur vehicle.

Northrop Grumman continues to incorporate updated technologies and its unique filament winding process to leverage heritage, flight-proven designs for high quality, low-cost and reliable strap-on variations. 

See firing of GEM 63 See firing of GEM 63XL

Commercial Rocket Motor Resources

CASTOR Motor in the hanger. Northrop Grumman

Castor Motor Series

A rocket motor inside a hangar

Orion Motor Series

Two white large rocket motor boosters at the Promontory, Utah, facility

GEM Series

Commercial Rocket Motors in the News

rocket taking off from launch pad

Northrop Grumman Finalizes Contract for GEM Solid Rocket Boosters

Rocket motor test in desert

Northrop Grumman Successfully Tests Abort Motor for NASA’s Orion Spacecraft

rocket ship abort system test

Northrop Grumman to Support NASA’s Artemis Missions with Motors for Orion Spacecraft’s Launch Abort System

rocket motor test

Northrop Grumman Completes Final Qualification Test for NASA’s Orion Launch Abort System Attitude Control Motor