Tonight's launch marked the first-ever liftoff for this particular Falcon 9's first stage. That's a rarity for SpaceX, which is known for its rocket reuse; one of the company's Falcon 9 boosters has 27 flights under its belt.

A United Launch Alliance Atlas V rocket and a SpaceX Falcon 9 rocket should lift off back-to-back from Florida's Space Coast. 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.

Amazon's first internet satellites are in orbit. United Launch Alliance's Atlas rocket blasted off Monday from Florida, carrying 27 of Amazon's Project Kuiper satellites.