United Launch Alliance delivered a classified US military payload to orbit Tuesday for the last time with an Atlas V rocket, ending 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 am EDT (10:45 UTC) Tuesday, propelled by a Russian-made RD-180 engine and five strap-on solid-fueled 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 with a US national security payload since 2007.
The US Space Force's Space Systems Command confirmed a successful conclusion to the mission, code-named USSF-51, on Tuesday afternoon. The rocket's Centaur upper stage released the top secret USSF-51 payload about seven hours after liftoff, likely in a high-altitude geostationary orbit over the equator. The military did not publicize the exact specifications of the rocket's target orbit.
"What a fantastic launch and a fitting conclusion for our last national security space Atlas V (launch),” said Walt Lauderdale, USSF-51 mission director at Space Systems Command, in a post-launch press release. “When we look back at how well Atlas V met our needs since our first launch in 2007, it illustrates the hard work and dedication from our nation’s industrial base. Together, we made it happen, and because of teams like this, we have the most successful and thriving launch industry in the world, bar none."
RD-180's long goodbye
The launch Tuesday morning was the end of an era born in the 1990s when US government policy allowed Lockheed Martin, the original developer of the Atlas V, to use Russian rocket engines during its first stage. There was a widespread sentiment in the first decade after the fall of the Soviet Union that the United States and other Western nations should partner 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 procuring new rockets to replace legacy versions of the Atlas, Delta, and Titan rocket families, which had been in service since the late 1950s or early 1960s.
Ultimately, the Air Force chose Lockheed Martin's Atlas V and Boeing's Delta IV rocket for development in 1998. The Atlas V, with its Russian main engine, was somewhat less expensive than the Delta IV and the more successful of the two designs. After Tuesday's launch, 15 more Atlas V rockets are booked to fly payloads for commercial customers and NASA, mainly for Amazon's Kuiper network and Boeing's Starliner crew spacecraft. The 45th and final Delta IV launch occurred in April.
Boeing and Lockheed Martin merged their rocket divisions in 2006 to form a 50-50 joint venture named United Launch Alliance, which became the sole contractor certified to carry large US military satellites to orbit until SpaceX started 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 sole-source contract for 36 Atlas V and Delta IV rocket booster cores. The litigation started soon after Russia's military occupation and annexation of Crimea, which prompted US government sanctions on prominent Russian government officials, including Dmitry Rogozin, then Russia's deputy prime minister and later the head of Russia's space agency.
Rogozin, known for his bellicose but usually toothless rhetoric, threatened to halt exports of RD-180 engines for US military missions on the Atlas V. That didn't happen until Russia finally stopped engine exports 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 fly out all of its remaining Atlas V rockets. This 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 US engines.
The SpaceX lawsuit, Russia's initial 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 dual-nozzle RD-180, made by a Russian company named NPO Energomash, consumes kerosene and liquid oxygen propellants and generates 860,000 pounds of thrust at full throttle.
Energomash exported the final batch of RD-180s to the United States in 2021, bringing the total number of deliveries to 122 engines. In the initial bulk order, each RD-180 engine was priced at approximately $10 million per unit. Energomash produced a few more RD-180s for ground testing in Russia, and those were never sent to the United States. Six RD-180 engines flew on Lockheed Martin's Atlas III rocket, which retired in 2005, and the rest have powered Atlas Vs into space.
The RD-180 engine never failed on a US military launch, and its only blemish across its entire flight history was a relatively slight performance shortfall on a commercial Atlas V launch in 2016. ULA has 15 more RD-180 engines in its inventory to cover the remaining backlog of Atlas V missions, which will likely stretch over the rest of the 2020s.
An all-American era
With the US military's reliance on Russian rocket engines no longer politically tenable, and SpaceX ready to launch military satellites at lower cost with an all-American, partially reusable rocket, ULA announced the development of a new launch vehicle named Vulcan in 2015. In that year's National Defense Authorization Act, Congress required the Air Force to transition off of the RD-180 engine, prompting a rush of Pentagon contracts to help fund new development of US rocket engines.
The military opened its military launch contracts for competition, and SpaceX started winning deals to launch GPS navigation satellites, spy platforms, and other national security payloads. In 2020, the Pentagon announced a bulk purchase of dozens of launches from ULA, with its new Vulcan rocket, and from SpaceX, with its Falcon 9 and Falcon Heavy launchers.
But the Vulcan rocket's first launch slipped several years, mainly due to delays with its BE-4 main engine, made by Blue Origin, Jeff Bezos' space company. This led the Space Force, which took over launch contracting from the Air Force, to award a larger share of launch deals to SpaceX than originally planned. The mission that launched Tuesday, known as USSF-51, also moved off of the Vulcan rocket and onto an Atlas V flight due to Vulcan delays.
“The Atlas family of rockets has played a pivotal role in the advancement of national security and space superiority since the 1950s,” said Tory Bruno, ULA’s president and CEO, in a statement. “Although today marks the final liftoff of a national security space mission aboard an Atlas rocket, we look forward to extending a legacy of outstanding teamwork and collaboration with the US Space Force as we launch future missions for our national security partners aboard the Vulcan rocket.”
The Vulcan rocket successfully launched on its first test flight on January 8 and is scheduled to fly again in mid-September on a second test flight. If that launch goes as well as the first one, the Space Force could certify the Vulcan rocket to begin launching actual payloads for the military by the end of this year.
Meanwhile, Blue Origin is nearing the finish line in the development of its heavy-lift rocket, the New Glenn, which could launch for the first time later this year. Once Blue Origin strings together a series of successful New Glenn launches, it will also be eligible to compete with ULA and SpaceX for at least some national security launch contacts.
