The increasing reliance on digital systems in modern rocketry, from design and manufacturing to launch operations and in-flight control, introduces significant cybersecurity vulnerabilities. This presentation, "Ignition Under Fire," explores the diverse attack vectors targeting rocket propulsion systems, examining potential consequences ranging from mission delays and data breaches to catastrophic failures. We will analyze the complex interplay of software, hardware, and network components within propulsion systems, identifying key weaknesses susceptible to exploitation. The presentation will delve into specific attack scenarios, software manipulation, sensor spoofing, and network intrusion, highlighting the potential impact on critical parameters like thrust, fuel flow, and combustion stability. Furthermore, we will discuss the unique challenges in securing these complex systems. We will explore how a Zero Trust architecture can be implemented to enhance security by enforcing strict access control, micro-segmentation, and continuous authentication and authorization throughout the propulsion system.