SpaceX launched 21 satellites into low-Earth orbit for the U.S. Space Development Agency (SDA) in mid-October 2025. The new Falcon 9 rocket lifted off from Vandenberg Space Force Base in California at 7:06 p.m. EDT, carrying the new batch of communication satellites. This mission marks the second of ten planned SDA launches to build the Tranche 1 Transport Layer- a secure satellite network designed to support military operations globally.
Soon after liftoff, the reusable Falcon 9 first stage successfully landed on a droneship in the Pacific Ocean, demonstrating SpaceX’s ongoing commitment to cost-effective space missions.
Expanding the SDA’s satellite constellation
The 21 satellites deployed during this launch form part of the SDA’s Tranche 1 Transport Layer, an essential segment of the broader Proliferated Warfighter Space Architecture (PWSA). Once complete, the full constellation will consist of 126 satellites in low-Earth orbit, enabling continuous, high-speed, and encrypted communications for the U.S. military.
The first group of 21 SDA satellites launched in September 2025 was manufactured by York Space Systems, while this latest batch was developed by aerospace leader Lockheed Martin, highlighting a growing collaboration between private space firms and defence contractors.
Building a global military communications network
The SDA’s new constellation is designed to facilitate secure, fast, and resilient data transmission, supporting tasks like encrypted messaging, missile tracking, and command operations across the globe.
SDA Acting Director Gurpartap “GP” Sandhoo stated that the new space layer will become “fully integrated into our warfare operations,” emphasising its strategic role in modern defence communication systems.
