A SpaceX Falcon 9 rocket on July 16 launched 21 satellites for the Space Development Agency. Credit: SpaceX livestream
WASHINGTON — A SpaceX Falcon 9 rocket on July 16 launched 21 satellites for the Space Force’s Space Development Agency, restarting deployment of the Pentagon’s first operational low Earth orbit military data network after a months-long pause.
The mission, designated T1TL-E, lifted off at 4:32 p.m. Eastern from Vandenberg Space Force Base in California. The satellites, built by York Space Systems, are the third batch of Tranche 1 Transport Layer spacecraft for SDA’s Proliferated Warfighter Space Architecture, or PWSA, and York’s second production lot for the tranche.
The launch marks a restart for one of the Space Force’s most closely watched satellite programs. SDA’s previous Tranche 1 launches placed 21 York satellites in orbit in September 2025 and 21 Lockheed Martin satellites in October 2025. With the latest mission, SDA will have 63 Tranche 1 Transport Layer satellites on orbit, half of the planned 126-satellite Transport Layer for Tranche 1.
The Transport Layer is the communications backbone of the PWSA, SDA’s planned network of low Earth orbit satellites designed to support missile warning, missile tracking and military data relay. The layer is intended to move data across space through optical intersatellite links and deliver it to ground systems, ships, aircraft and other military users.
