In the quiet early hours of August 2, 2023, at 12:49 AM EDT, history was being made. A Northrop Grumman Antares rocket majestically ascended from the Mid-Atlantic Regional Spaceport in Virginia. The payload? A Cygnus cargo spacecraft, packed to the brim with supplies for the International Space Station (ISS). This launch marked the 19th and final mission of the laudable Antares 230 series, a key logistics provider for the ISS since its first successful flight in 2016.
Antares boasts a unique tapestry of history and design. The brainchild of Orbital Sciences Corporation, the company underwent several transformations, first merging with ATK to form Orbital ATK, before finally being acquired by Northrop Grumman in 2018. The rocket's first stage found its genesis in Ukraine, thanks to the combined expertise of Yuzhnoye Design Office and Yuzhmash, utilizing two Russian-made RD-181 engines for propulsion. Northrop Grumman designed the second stage, centered around the Castor 30XL solid rocket motor.
In 2008, NASA selected the Antares rocket for its Commercial Orbital Transportation Services (COTS) program, an initiative designed to spur private sector participation in ISS resupply missions. The first Antares mission launched in 2013, carrying a test model of the Cygnus spacecraft. Since then, this powerhouse rocket has successfully completed 18 missions under the Commercial Resupply Services (CRS) contract, delivering over 40,000 kg of cargo to the ISS.
However, Antares's journey was not without obstacles. A catastrophic explosion in 2014 marred its history when an Antares rocket detonated shortly after liftoff, resulting in the loss of a Cygnus spacecraft and severe damage to the launch pad. The investigation found a faulty turbopump in one of the engines – originally designed in the 1960s and refurbished by Aerojet Rocketdyne – to be the cause. In response, Orbital ATK revamped the rocket with new RD-181 engines, a strengthened first stage structure, and enhanced avionics. This new-and-improved version, the Antares 230, took to the skies again in 2016.
Antares also grappled with geopolitical tumult. The rocket's first stage was produced in Ukraine, a country embroiled in conflict with Russia since 2014. When Russia invaded Ukraine in February 2022, it disrupted Antares's supply lines, leading Northrop Grumman to phase out Antares in favor of their own OmegA rocket for future CRS missions. The first OmegA mission is slated for 2024.
The final Antares launch was a poignant milestone for those involved with the program. The rocket executed its mission flawlessly, depositing the Cygnus spacecraft into orbit. Named SS Ellison Onizuka in honor of the first Asian American astronaut who tragically perished in the Challenger disaster, the spacecraft bore over 3,700 kg of cargo, comprising scientific experiments, hardware, crew supplies, and student projects. Cygnus will spend approximately three months attached to the ISS before departing and safely disposing of waste during a controlled reentry.
As we bid farewell to Antares, we honor its legacy as a pioneer and workhorse of commercial spaceflight. It has unequivocally demonstrated that private entities can deliver reliable and cost-effective access to low Earth orbit while furthering the scientific and educational objectives of the ISS program. More than anything, Antares has been a beacon of international cooperation and innovation, critical pillars for the ongoing journey of human space exploration.
