What: Minotaur IV rocket by Northrop Grumman Corp. The vehicle employs three government-furnished solid rocket motors from decommissioned Peacekeeper ICBMs plus a commercial solid-rocket upper stage. The vehicle can carry payloads up to 3,814 pounds to low-Earth orbit. 

When: No earlier than 12:33 p.m. Wednesday. The launch window remans classified due to the top-secret payload, but notices released ahead of the liftoff say it won’t launch after 2:26 p.m.  

Where: Space Launch Complex-8, the most southern facility for launching rockets at Vandenberg Space Force Base in Santa Barbara County.

Landing: None.

Why: Deliver a National Reconnaissance Office payload to space for a mission dubbed NROL-174.

Weather: The forecast calls for cloudy and drizzly conditions which may hamper views of the rocket’s departure, but won’t necessarily interfere with the flight.

Watch: A webcast of the countdown and liftoff is not planned. 

To watch the liftoff in person, the Lompoc Valley has multiple locations offering views but the launch pad isn’t visible from off base.

Other viewing sites include the peak of Harris Grade Road, west of Lompoc’s city limits and around Vandenberg Village, including near the intersection of Moonglow and Stardust roads. 

Vandenberg launches close to sunset or sunrise can be especially picturesque. If skies are clear, the rocket’s departure might be visible from elsewhere around California and, under certain conditions, other Western states.