SpaceX successfully launched USSF-259, a classified national security mission for the United States Space Force, on September 16, 2026, at 6:07 p.m. Pacific Time from Vandenberg Space Force Base in California. The specific payload details remain confidential; however, analysts suggest the mission likely carries a batch of classified low Earth orbit satellites based on SpaceX's Starshield satellite bus. This assessment is supported by analysis of ascent rocket stage drop zones, which align with patterns observed from previous Space Development Agency Transport Layer launches, indicating a connection to the U.S. military's emerging space architecture.

The Falcon 9 Block 5 rocket lifted off from Space Launch Complex 4 East at Vandenberg SFB, SpaceX's primary West Coast launch facility dedicated to national security missions. The launch had been rescheduled from September 15 to September 16 due to weather and other technical considerations, with the launch window originally targeted between 6 p.m. and 10 p.m. Pacific Time.

The mission achieved a successful outcome, with the vehicle performing nominally throughout its ascent. The launch represents continued SpaceX operations supporting U.S. military space capabilities and demonstrates the company's ongoing role as the primary launch provider for classified Department of Defense and Space Force payloads.