SpaceX is scheduled to launch a Falcon 9 rocket from Vandenberg Space Force Base in California this weekend on a classified U.S. Space Force mission called USSF-366. The company has said it will livestream the event, while local authorities and SpaceX have warned residents they may hear sonic booms as the booster returns through the atmosphere.
- SpaceX will launch classified USSF-366 from Vandenberg with a livestream beginning about 10 minutes before liftoff.
- Liftoff is targeted for 4:47 p.m. PT Saturday, with a Sunday backup window at 2:38 p.m.; details about the payload remain undisclosed.
- The Falcon 9 booster assigned to the flight is on its 18th mission and is expected to land on the droneship Of Course I Still Love You.
Confirmed details and schedule
SpaceX is targeting 4:47 p.m. Pacific Time on Saturday for liftoff of USSF-366 from Vandenberg, with a backup opportunity set for 2:38 p.m. Sunday, according to company information reported by KTLA and other local outlets. SpaceX plans to begin its public webcast roughly 10 minutes before scheduled liftoff.
What is known about the flight hardware
The mission will use SpaceX’s two-stage, 230-foot Falcon 9 rocket. SpaceX said the booster assigned to this flight is on its 18th mission. Reported prior flights for that first-stage booster include NROL-126, Transporter-12, SPHEREx, NROL-57 and 13 Starlink launches. After stage separation, the booster is expected to attempt a controlled landing on SpaceX’s ocean-going droneship, Of Course I Still Love You, in the Pacific.
Classified payload: limited public information
Officials have released few public details about what USSF-366 will carry. Local reports describe the mission as classified and note that multiple spaceflight outlets have suggested the launch could involve deploying a group of military satellites into low-Earth orbit, but those outlets are not identified in the public reporting. KTLA and The Desert Sun make clear that the payload contents have not been disclosed.
Local impacts: sonic booms, viewing and livestream
SpaceX and Vandenberg warned that residents of Santa Barbara, San Luis Obispo and Ventura counties could hear one or more sonic booms as the returning booster re-enters at supersonic speed. Areas nearer the base may also notice a low rumble at liftoff, Vandenberg officials said in local reporting.
The launch is visible from several coastal and inland locations when conditions are clear. Local news outlets and tourism bureaus have previously published lists of common public viewing spots for Vandenberg launches; past SpaceX flights from the base have been visible as far as Santa Barbara and Los Angeles on clear days. SpaceX will also provide a livestream of the launch starting about ten minutes before liftoff for viewers who prefer to watch online.
Context: Vandenberg operations and launch cadence
Vandenberg Space Force Base in Santa Barbara County is a regularly used West Coast site for polar and southern-trajectory launches. Local coverage earlier in 2026 noted a high tempo of launches from California and reported that SpaceX has helped the state reach significant launch milestones this year. Launch windows and target times are subject to change because of weather or technical issues.
Why the mission is described as classified
The U.S. Space Force sometimes conducts missions with classified details for national security reasons; media reporting on those flights therefore often provides only the launch timeframe and vehicle. In this case, local outlets reporting on SpaceX and Vandenberg statements have reiterated that the mission is being described as classified and that the payload has not been publicly identified.
Outstanding questions
- What exactly is aboard USSF-366: no official disclosure has been made about the payload’s type, operator or mission.
- Operational objectives and orbital parameters: public reporting has not provided confirmed orbital details for the flight.
- Potential downstream effects: without confirmed payload information, it is not possible to assess operational impacts such as communications coverage, reconnaissance capability or defensive measures.
Practical information for residents and viewers
- Check SpaceX’s webcast to view the launch; the company typically begins streaming about ten minutes before liftoff.
- Be prepared for loud noises: authorities have warned local residents that sonic booms and the initial low rumble from liftoff are possible in nearby counties.
- Launch times can change: reporters noted that weather or technical issues can prompt postponements; a backup attempt was identified for Sunday afternoon.
Sources and attribution
This story is based on local reporting and SpaceX statements compiled by KTLA, The Desert Sun and the Ventura County Star. Those outlets reported the scheduled liftoff times, the mission designation USSF-366, the booster’s flight history and the planned droneship recovery, and noted that mission details remain classified and have not been publicly released.
Orbital Affairs will update this article if SpaceX or the U.S. Space Force provide additional official details after the launch webcast or through formal notices.
