Falcon 9 Live coverage: Space Development Agency, SpaceX to launch next-gen national security satellites September 10, 2025 Will Robinson-Smith The 21 satellites from York Space Systems are the first in the SDA’s Tranche 1 Transport Layer satellite constellation. SpaceX is targeting liftoff from pad 4 East at Vandenberg Space Force Base at 7:12 a.m. PDT (10:12 a.m. EDT / 1412 UTC).