The Air Force has activated two space-based tracking satellites for the Geosynchronous Space Situational Awareness Program.

GSSAP 3 and 4 were launched into orbit on Aug. 19, 2016, and activated by the 1st Space Operations Squadron at Schriever Air Force Base, Colorado, on Sept. 12 of this year.

The first two GSSAP satellites were launched in 2015.

“This addition to GSSAP is vital to expand 1 SOPS’s space-based space situational awareness mission,” according to the Air Force. “It not only provides a significant improvement in space object characterization, but also in detecting threats. Because of its near-geosynchronous orbit, it has a clear and distinct vantage point to avoid the weather interruptions that can limit ground-based space surveillance systems.”