On May 22, a SpaceX Falcon 9 rocket launched an undisclosed number of small spacecraft for the National Intelligence Agency. Falcon 9 took off from Vandenberg Space Force Base in California at 4:00 a.m. EST.

The secret mission, called NROL-146, was SpaceX’s 52nd launch this year and the fifth Falcon 9 launch for NRO. The first stage of the rocket, which made its 16th flight after separating from the upper stage, landed on an unmanned ship parked in the Pacific Ocean.

At NRO’s request, SpaceX did not show images of the rocket’s upper stage and stopped webcasting after the first stage landed; This marked the 310th time the company had recovered its first stage launch vehicle.

NRO develops and operates the U.S. government’s secret surveillance and intelligence satellites. NROL-146 is the agency’s first deployment of a new satellite constellation created by SpaceX and Northrop Grumman.

NRO did not disclose how many satellites were launched during this mission or the projected size of the new group. Agency officials have previously said six launches are planned for NRO’s common small satellite architecture in 2024.

NRO said it aims to quadruple the number of spacecraft in orbit. Smaller and more satellites would allow for much more frequent monitoring of critical areas of interest, leading to faster delivery of critical intelligence, officials said.