Tranche 1 Transport Layer B is one of six missions by the United States Space Force Space Development Agency (SDA) for the Proliferated Warfighter Space Architecture (PWSA) Tranche 1 Transport Layer constellation, which will provide assured, resilient, low-latency military data and connectivity worldwide to the full range of warfighter platforms from Low Earth Orbit satellites. The constellation will be interconnected with Optical Inter-Satellite Links (OISLs) which have significantly increased performance over existing radio frequency crosslinks. It is expected to operate over Ka band, have stereo coverage and be dynamically networked for simpler hand-offs, greater bandwidth and fault tolerance. This launch carries 21 satellites manufactured by York Space Systems. September 10, 2025 at 14:12 UTC · Launch Successful Falcon 9 Block 5 — SpaceX, to Polar Orbit Space Launch Complex 4E, Vandenberg SFB, CA, USA The world's 7058th orbital launch attempt, and 209th of 2025. https://www.youtube.com/watch?v=AcoFvwsuIQI https://www.youtube.com/watch?v=_i3mvsEWQE8 Data: Launch Library 2, The Space Devs. Mission patch: via The Space Devs.