First, ULA is targeting 7 p.m. to launch the Atlas V — which is outfitted with five solid rocket boosters — and deploy the first production batch of Amazon Project Kuiper broadband satellites into low-Earth orbit. The launch window lasts two hours, until 9 p.m., and the rocket will fly along a northeasterly trajectory.

Liftoff is now set for 10:09 p.m. from Cape Canaveral Launch Complex 40. The Falcon 9 rocket will be carrying the Starlink 12-23 mission to orbit. This is the latest batch of SpaceX's Starlink internet satellites. Should SpaceX not be able to launch at 10:09 p.m., opportunities exist until 1:49 a.m. (April 28).