Redundancy, the inclusion of multiple independent elements to perform a task, is fundamental to enhancing the reliability of complex systems. A notable example is NASA’s Apollo 10 mission, where redundancy enabled mission continuity despite a fuel cell failure. However, incorporating redundancy involves balancing reliability goals with constraints such as cost, weight, and size. This paper explores a redundancy allocation model focused on optimizing system reliability for systems composed of multiple independent subsystems arranged in parallel. Each subsystem is built from identical components, and the system’s overall reliability is determined by the product of individual subsystem reliabilities. The model seeks the optimal number of components per subsystem to meet a defined reliability target, using rational parameters to represent component failure probabilities and required system reliability. This approach provides a structured framework for designing resilient systems while effectively managing limited resources