Atlas 5 rocket cores

Amid repeated inquiries from lawmakers concerned about recent events in Ukraine, senior Pentagon officials, including Defense Secretary Chuck Hagel, have vowed to re-examine the use of a Russian-built engine in launching U.S. national security space missions.

Russia’s occupation of Ukraine’s Crimea region, and resulting tensions with the United States, have led several lawmakers to fret aloud about the continued availability of the Russian-built RD-180 engine that powers the main stage of United Launch Alliance’s Atlas 5 rocket. ULA, which launches nearly all U.S. military and intelligence satellites, relies on two vehicles, the Atlas 5 and Delta 4.

Hagel told the House Appropriations defense subcommittee March 13 that the Pentagon would once again review its reliance on the RD-180. U.S. Air Force Secretary Deborah Lee James delivered a similar message March 14 to the House Armed Services Committee.

Gen. William Shelton, commander of Air Force Space Command, said in January that the service was studying the feasibility of setting up a U.S. production line for the RD-180. ULA says it has at least a two-year stockpile of the engines. 

Concerns about RD-180 reliability predate the Crimea occupation. Last year, for example, Russian press reports quoted a Russian government official as saying a ban on RD-180 exports to the United States was under consideration.