The Antares rocket has a rich history that reflects the evolution of U.S. commercial spaceflight and the strategic partnerships needed to meet NASA's needs. Originally developed by Orbital Sciences Corporation, Antares has been a vital player in NASA’s Commercial Resupply Services (CRS) missions to the International Space Station (ISS). The rocket’s development has seen multiple milestones, design enhancements, and corporate transitions, including its stewardship under Orbital ATK and later Northrop Grumman.
Early Development: Orbital Sciences Corporation
In 2008, Orbital Sciences Corporation initiated the development of Antares, then called Taurus II, to compete for NASA’s CRS contracts. The rocket was designed as a medium-lift vehicle capable of delivering cargo to low Earth orbit (LEO). Its key components were sourced from both international and domestic partners:
First Stage: Developed with Ukraine's Yuzhnoye Design Bureau, featuring two Russian-built AJ26 engines, which were modified versions of the Soviet-era NK-33 engines.
Second Stage: Orbital drew on its extensive experience in solid rocket propulsion, utilizing the Castor 30 series, derived from the Castor family of motors.
The Castor solid rocket motor family has a heritage that dates back to the Scout rocket, developed in the late 1950s and early 1960s by NASA and industry partners. The Scout rocket was one of the first all-solid-fuel launch vehicles, providing a reliable platform for launching small payloads into orbit. This legacy of solid propulsion was carried forward by Orbital, with the Castor family evolving into more advanced configurations, including those used on Antares. This connection to the Scout program highlights Antares’ ties to pioneering American rocketry.
Antares Rocket on Pad 0A. C. Steve Hammer photo
Antares was specifically designed to carry Orbital's Cygnus spacecraft, an uncrewed cargo vehicle for ISS resupply missions. The rocket’s first successful flight occurred on April 21, 2013, from NASA’s Wallops Flight Facility in Virginia, marking its operational debut.C. Steve Hammer photo
Supporting NASA's CRS Program
Antares became an essential component of NASA’s CRS program, flying its first operational mission, CRS Orb-1, in January 2014. Alongside SpaceX’s Falcon 9 and Dragon spacecraft, Antares and Cygnus ensured the uninterrupted delivery of cargo, scientific experiments, and equipment to the ISS.
Formation of Orbital ATK
In 2015, Orbital Sciences merged with Alliant Techsystems (ATK) to form Orbital ATK. The merger combined Orbital’s expertise in satellite and launch vehicle development with ATK’s deep experience in propulsion systems, including the Castor series. This synergy allowed the Antares program to recover from challenges and improve its capabilities.
October 2014 Failure: Turning Point
On October 28, 2014, during the CRS Orb-3 mission, an Antares rocket failed shortly after liftoff. The failure was traced to one of its AJ26 engines. This incident spurred Orbital ATK to replace the AJ26 engines with the more modern and reliable RD-181 engines, built by Russia’s NPO Energomash. These engines provided higher thrust, greater reliability, and improved performance, leading to the upgraded Antares 230 series.
The revamped Antares 230 returned to flight on October 17, 2016, successfully completing its mission and restoring confidence in the program.
Northrop Grumman Acquisition
In 2018, Orbital ATK was acquired by Northrop Grumman, forming Northrop Grumman Innovation Systems. Under Northrop’s leadership, the Antares rocket became a critical part of NASA’s CRS-2 contracts, ensuring continued resupply missions to the ISS through the late 2020s.
The Antares 230+ variant, introduced under Northrop Grumman, featured incremental upgrades, allowing the rocket to carry heavier payloads and maintain its reliability.
Antares 330: A Fully Domestic Evolution
Geopolitical tensions in 2022, including strained U.S.-Russia relations, prompted Northrop Grumman to accelerate the development of a fully domestic version of the Antares rocket. The new configuration, Antares 330, will replace the Ukrainian-built first stage and Russian RD-181 engines with components manufactured in the United States.
Northrop Grumman partnered with Firefly Aerospace to develop the Antares 330. The rocket will feature:
A U.S.-built first stage.
Firefly’s Miranda engines for greater thrust and reliability.
Enhanced payload capacity, designed to support future commercial and government missions.
Antares 330 is expected to debut in the mid-2020s, ensuring the rocket's continued relevance in the evolving space industry.
Legacy and Impact
The Antares rocket has played a pivotal role in advancing commercial spaceflight and supporting NASA’s ISS missions. Its Castor 30 second stage, tracing its lineage back to the Scout rocket, underscores the continuity of innovation in solid rocket propulsion over decades of U.S. space exploration.
From its origins under Orbital Sciences to its modernization under Northrop Grumman, Antares exemplifies adaptability, resilience, and collaboration. Its upcoming evolution into the fully domestic Antares 330 ensures its legacy will endure as a key player in the future of space exploration.
All photos by C. Steve Hammer
Castor engine in the Horizontal Integration Facility.
View of an Antares launch a meteor and a satellite flare from Smith Mountain Lake in Bedford County, Virginia