"Hi-Rel" stands for "High Reliability". It refers to the design, testing, and manufacturing practices that are used to ensure the reliability and performance of aerospace systems and components.
Hi-Rel systems are typically required to operate under extreme conditions, such as high levels of stress, temperature, radiation, or vibration. They are also expected to have a high level of performance and functionality over a long period of time, often under challenging or hazardous conditions.
To meet these requirements, Hi-Rel systems are designed and built using specialized materials, processes, and testing procedures that are designed to ensure their reliability and performance. This may include the use of redundant or fail-safe components, rigorous testing and inspection procedures, and the use of special materials and fabrication techniques.
Hi-Rel systems are commonly used in a variety of aerospace applications, including military and defense systems, satellite and space exploration systems, and commercial aviation systems. They are also used in other industries that require high levels of reliability and performance, such as nuclear power and medical devices.