Live coverage: Atlas 5 countdown and launch journal

One of the largest satellites in the world will launch aboard America’s biggest operational booster Thursday, riding that power to a listening post 22,300 miles above the planet for its clandestine eavesdropping mission, all indications suggest.

A Falcon 9 rocket launching an Argentine Earth-observing satellite streaked across the skies of Southern California on Sunday night, then its booster stage returned to Vandenberg Air Force Base for an on-target landing, the first by SpaceX on the West Coast.

A United Launch Alliance Delta 4-Heavy rocket, crowned by a solid-fueled upper stage kick motor, will send NASA’s Parker Solar Probe on a speedy voyage through the inner solar system following liftoff from Cape Canaveral.