WASHINGTON — A United Launch Alliance Atlas 5 rocket featuring a new variant lifted off Dec. 12 from Vandenberg Air Force Base, California, carrying a classified payload for the U.S. National Reconnaissance Office.

The launch of the NROL-35 mission occurred at 7:13 p.m. local time, according to the NRO, which buys and operates U.S. spy satellites. Almost all NRO missions are classified, which means few details are released.

Denver-based ULA said the launch marked the first use of a new variant of the RL-10 engine, dubbed RL-10C, to power the Atlas 5 Centaur upper stage. The engine, supplied by Aerojet Rocketdyne, was originally designed for use on ULA’s Delta 4 rocket but was converted for the Atlas 5.

Launch of NROL-35 from Vandenberg Air Force Base, California. Credit: ULA
Atlas 5 lofts NROL-35. Credit: ULA.

“ULA is extremely pleased with this first flight of the new, RL10C-1 engine,” Jim Sponnick, ULA’s vice president of Atlas and Delta programs, said in a Dec. 13 press release. “We have been working closely with Aerojet Rocketdyne and our Air Force customers for several years to develop and extensively test this next-generation engine to enable the most reliable and cost-effective upper stage propulsion for our Atlas and Delta programs.”

The rocket also included four solid-fuel strap-on motors.

NROL-35 was the NRO’s third launch in 2014 and only mission from Vandenberg, the agency said. The next NRO mission is expected to launch in spring 2015, the agency said.


Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.