The chronological sequence of liquid rocket engine ignition—involving propellant priming, ignition source activation, and subsequent chamber pressure buildup—is a matter of standard engineering definition and everyday technical observation, requiring no citation.
The claim outlines the foundational engineering steps of starting a liquid rocket engine (propellant introduction, ignition, and pressure stabilization). This is a textbook operational sequence and textbook description of a transient start-up process, making it common knowledge in aerospace engineering.