Instrumentation and Control Approaches for NTP, NEP, and FSP Identification and Placement

The integration of instrumentation and control (I&C) systems in nuclear power and propulsion applications is a critical enabler of reliable and safe operation, particularly for space-based systems where autonomy and radiation hardness are essential. This paper examines historical and contemporary approaches to I&C in Nuclear Thermal Propulsion (NTP), Nuclear Electric Propulsion (NEP) and Fission Surface Power (FSP) systems with a focus on insights drawn from the foundational work of L3Harris. The discussion includes sensor selection and placement, radiation-hardened electronics, fault-tolerant control architectures, and the interface between propulsion systems, power systems and space vehicle avionics. Lessons learned from early space nuclear programs such as Nuclear Engine for Rocket Vehicle Application (NERVA) and Systems for Nuclear Auxiliary Power (SNAP, including SP-100), Project Prometheus (Jupiter Icy Moons Orbiter-JIMO) are revisited in the context of modern nuclear system demands, including lunar surface power needs, crewed Mars exploration, and deep space logistics. The paper concludes with recommendations for future I&C design strategies, emphasizing modularity, diagnostics, and robust autonomy.