On September 10, 2025 at 7:12 a.m. PDT (10:12 a.m. EDT), SpaceX launched the first Tranche 1 Transport Layer mission for the Space Development Agency (SDA) from Vandenberg Space Force Base’s Launch Complex 4E, California. This marks the start of an important new era in military satellite communications.
The rocket carried 21 satellites, all built by York Space Systems, into low Earth orbit as part of the Proliferated Warfighter Space Architecture (PWSA). These spacecraft are designed to provide low-latency, secure data transport and missile-tracking capabilities to support U.S. military operations.
The booster used for this mission was Falcon 9 first stage B1093, which was launched for its sixth flight—all prior flights having supported Starlink missions. About 8.5 minutes after liftoff, the booster successfully landed on the droneship Of Course I Still Love You in the Pacific Ocean.
For the SDA, this launch initiates a rollout of 154 operational satellites, including 126 Transport Layer vehicles and 28 Tracking Layer satellites. Launches are planned monthly over the next ten months to complete the full Tranche 1 constellation
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