US spy satellite launched into orbit for the last time aboard a Delta 4 Heavy rocket from California

A secret companion The US National Intelligence Service launched the United Launch Alliance’s Delta 4 Heavy rocket into orbit on Saturday. The NROL-91 spy satellite launched at 3:25 p.m. from Vandenberg Space Force Base in Santa Barbara County, California.

This was the last Delta 4 launch from the West Coast. Additional launches are planned from Florida before the Deltas are replaced by ULA’s next-generation Vulcan Centaur rockets.

“Delta IV Heavy has been an integral part of NRO’s history, helping us build the architecture for the world’s best space intelligence, surveillance and reconnaissance,” said NRO Director Dr. Chris Scolese in statement.

The Delta IV Heavy configuration was first launched in December 2004. It was the 387th flight of a Delta rocket since 1960 and the 95th and final launch from Vandenberg.

The National Intelligence Agency is the government agency responsible for the design, construction, launch, and maintenance of U.S. spy satellites that provide intelligence to policymakers, the intelligence community, and the Department of Defense.

SpaceX Falcon 9 rockets also increased classified National Intelligence Service payloads into orbit. U Aprilbased on the timing of the launch and a number of other factors, independent space analysts suggested that the Falcon 9 likely launched two Naval Ocean Surveillance System, or NOSS, satellites, which work in pairs to electronically monitor and locate ships at sea.