SpaceX is targeting Tuesday, 15 September 2026 for a Falcon 9 launch of the classified USSF-259 mission from Space Launch Complex 4E at Vandenberg Space Force Base.
The four-hour window opens at 6:00 p.m. PT / 9:00 p.m. ET and runs through 10:00 p.m. PT Tuesday / 1:00 a.m. ET Wednesday. The backup window is on Wednesday, 16 September at the same times, just in case Tuesday gets scrubbed.
USSF-259 is a national-security payload, and the details for what is onboard is classified, as usual, just like the previous USSF-153 launch that was scheduled for Thursday, 10 September. These launches from Vandenberg Space Force Base are fairly regular, and will likely be one of the long-term uses for Falcon 9 as the Starlink mission is eventually handed over to Starship.
Landing in the Pacific
After stage separation, the first stage is planned to land on Of Course I Still Love You, stationed in the Pacific Ocean. For SpaceX, this is a routine orbital insertion with a routine droneship recovery on the west coast, with the booster coming downrange at sea.
For those who followed Thursday’s USSF-153 result from the same pad family, the pattern is familiar: SLC-4E for the climb and OCISLY for the landing.
13th Flight for This Booster
SpaceX says this will be the 13th flight for the first-stage booster supporting the mission. Prior flights the company lists for that booster include Sentinel-6B, Twilight, NROL-172, Transporter-17, and eight Starlink missions.
A live webcast is set to begin about 10 minutes before liftoff on the SpaceX mission page and on X at @SpaceX. SpaceX also notes that residents of Santa Barbara, San Luis Obispo, and Ventura counties may hear one or more sonic booms during the launch, depending on weather and other conditions.
