ULA set to test-fire Vulcan Centaur rocket after delays.

United Launch Alliance's first Vulcan Centaur rocket is set to undergo a critical test-firing of its Blue Origin-built BE-4 main engines at Cape Canaveral Space Force Station. The test was delayed from last month by an issue with the booster engine ignition system. The Flight Readiness Firing will demonstrate day of launch timelines and procedures, propellant loading operations, and the countdown sequence for the Vulcan Centaur rocket through ignition of the booster’s twin BE-4 engines.