SpaceX launching 2nd classified mission for US Space Force in less than a week tonight: Watch it live

SpaceX will launch its second classified mission for the U.S.

Space Force in less than a week tonight (Sept.

15), and you can watch the action live.

A Falcon 9 rocket is scheduled to lift off from California's Vandenberg Space Force Base today, during a four-hour window that opens at 9 p.m.

EDT (6 p.m. local California time; 0100 GMT on Sept.

16).

You can watch it live via SpaceX beginning about 10 minutes before launch.

We don't know much about tonight's mission, which is called USSF-259.

And we're unlikely to learn much from the webcast, which is expected to end shortly after the Falcon 9's first stage returns to Earth for its drone-ship landing about 8.5 minutes after launch.

That touchdown will be the 13th for this particular booster, which is designated 1097.

One of the booster's recent landings was a big milestone for SpaceX .

This past April, B1097 pulled off SpaceX's 600th touchdown of an orbital-class rocket , during a launch that sent 25 of the company's Starlink internet satellites to low Earth orbit .

Tonight's mission will be the second that SpaceX flies for the U.S.

Space Force in a five-day span: A Falcon 9 launched the similarly classified USSF-153 from Vandenberg on Sept.