After a decade-long effort, the United Launch Alliance (ULA) successfully delivered a classified US military payload into orbit on Tuesday, marking the final use of a Russian-made RD-180 engine in national security missions. The Atlas V rocket, equipped with five strap-on solid-fueled boosters, lifted off from Cape Canaveral Space Force Station in Florida at 6:45 am EDT on Tuesday for its 101st launch since its debut in 2002. This mission, named USSF-51, was the 58th and final Atlas V launch carrying a US national security payload since 2007.

The US Space Force's Space Systems Command confirmed the successful deployment of the top-secret USSF-51 payload into a likely high-altitude geostationary orbit over the equator about seven hours after liftoff. Walt Lauderdale, the mission director, expressed satisfaction with the Atlas V's performance in meeting national security needs since its first launch in 2007, highlighting the collaboration between the nation's industrial base and the success it has brought to the launch industry.

The era of US military rockets relying on Russian engines dates back to the 1990s when Lockheed Martin, the original developer of the Atlas V, was permitted to incorporate the RD-180 engines into their design. This decision was influenced by post-Soviet sentiments and the desire to prevent aerospace workers in Russia from seeking employment with potential adversaries.

Boeing and Lockheed Martin's joint venture, United Launch Alliance, had been the sole contractor certified to launch large US military satellites until SpaceX entered the scene in 2018. SpaceX's challenge to the Air Force's contract awarded to ULA in 2014, coupled with Russia's ban on exporting RD-180 engines to the US following the invasion of Ukraine in 2022, hastened the end of the Atlas V rocket's utility and the use of Russian engines in US military launches.

The Atlas V's retirement marks a historic shift towards all-American launch technology, with future launches slated for commercial customers and NASA, including missions for Amazon's Kuiper network and Boeing's Starliner crew spacecraft. The collaboration between US aerospace companies and the successful transition away from reliance on Russian engines demonstrate the nation's commitment to securing its space assets with domestic launch capabilities.