United Launch Alliance on Tuesday launched a classified U.S. military payload into orbit for the final time on an Atlas V rocket, marking the end of the Pentagon’s use of Russian rocket engines as national security missions transition to all-American launchers.
The Atlas V rocket lifted off from Cape Canaveral Space Force Station in Florida at 6:45 a.m. EDT (10:45 UTC) on Tuesday, powered by a Russian RD-180 engine and five strap-on solid-propellant boosters in its most powerful configuration. This was the 101st launch of an Atlas V rocket since its debut in 2002, and the 58th and final Atlas V mission carrying a U.S. national security payload since 2007.
The U.S. Space Force’s Space Systems Command confirmed Tuesday afternoon the successful completion of the mission, code-named USSF-51. The rocket’s Centaur upper stage released the top-secret USSF-51 payload about seven hours after launch, likely into a high-altitude geostationary orbit above the equator. The military did not release the exact specifications of the rocket’s intended trajectory.
“What a fantastic launch and a fitting conclusion to our last national security space Atlas V (launch),” said Walt Lauderdale, USSF-51 mission director at Space Systems Command, in a press release after the launch. “As we look back at how well Atlas V has met our needs since our first launch in 2007, it illustrates the hard work and dedication of our nation's industrial base. Together, we made it happen, and it's because of teams like this that we have the most successful and thriving launch industry in the world, bar none.”
The long goodbye to the RD-180
Tuesday morning's launch marked the end of an era established in the 1990s, when U.S. government policy allowed Lockheed Martin, the Atlas V's original developer, to use Russian rocket engines for its first stage. In the decade after the fall of the Soviet Union, there was widespread sentiment that the United States and other Western nations should work with Russia to keep the country's aerospace workers employed and prevent “rogue states” like Iran or North Korea from hiring them.
At the time, the Pentagon was looking for new rockets to replace the older versions of the Atlas, Delta and Titan rocket families, which had been in service since the late 1950s or early 1960s.
Ultimately, in 1998, the Air Force settled on Lockheed Martin's Atlas V and Boeing's Delta IV rockets. The Atlas V, with its Russian main engine, was slightly less expensive than the Delta IV and the more successful of the two designs. After Tuesday's launch, another 15 Atlas V rockets have been booked to carry payloads for commercial customers and NASA, primarily Amazon's Kuiper network and Boeing's Starliner crew spacecraft. The 45th and final Delta IV launch took place in April.
Boeing and Lockheed Martin merged their rocket divisions in 2006 into a 50-50 joint venture called United Launch Alliance. United Launch Alliance became the only contractor certified to launch large U.S. military satellites into orbit until SpaceX began launching national security missions in 2018.
SpaceX filed a lawsuit in 2014 to protest the Air Force’s decision to award ULA a multibillion-dollar contract for 36 Atlas V and Delta IV rocket booster cores. The lawsuit began shortly after Russia’s military occupation and annexation of Crimea, which led to U.S. government sanctions against prominent Russian officials, including Dmitry Rogozin, then Russia’s deputy prime minister and later head of the Russian space agency.
Rogozin, known for his belligerent but generally toothless rhetoric, threatened to halt the export of RD-180 engines for U.S. military missions on the Atlas V. That only happened when Russia finally stopped exporting engines to the United States in 2022, following its full-scale invasion of Ukraine. At that point, ULA already had all the engines it needed to launch all of its remaining Atlas V rockets. The export ban had a larger effect on Northrop Grumman’s Antares rocket, which also used Russian engines, forcing the development of a brand new first-stage booster with American engines.
The SpaceX lawsuit, Russia’s first military incursions into Ukraine in 2014, and the resulting sanctions marked the beginning of the end for the Atlas V rocket and ULA’s use of the Russian RD-180 engine. The twin-nozzle RD-180, made by a Russian company called NPO Energomash, burns kerosene and liquid oxygen as fuel and generates 860,000 pounds of thrust at full throttle.
