SpaceX Falcon 9 launched the USSF-259 mission from Space Launch Complex 4E(SLC-4E), Vandenberg Space Force Base on Wednesday(Sept. 16), at 0107 UTC, carrying classified payload for the U.S. Space Force’s Space Systems Command (SSC) under the National Security Space Launch (NSSL) Phase 3 Lane 1 contract.
Following stage separation, the Falcon 9 first-stage booster, B1097 performed a controlled landing on the Of Course I Still Love You droneship in the Pacific Ocean, about 8 minutes after liftoff. B1097 completed its 13th flight, having previously supported missions including Sentinel-6B, Twilight, NROL-172, Transporter-17, and eight Starlink deployments.
Meanwhile the Falcon 9 upper stage flew a southerly trajectory to deploy its payload into a low Earth orbit inclined roughly 80 degrees from the Equator.
This mission, identified in public documents as TH-1, marks the third recent national security launch for SpaceX procured by SSC, following USSF-366 (launched August 15) and USSF-153 (launched September 10). Previous missions in this series, identified as R1 and R2, each carried 23 satellites.