A methodology for estimating reliability of SmallSat computers in radiation environments

High-performance computing is becoming a requirement for space computing due to the rapid advancement of technology in instruments and sensors and increasing demand for sensor and autonomous processing. The mentality for building spacecraft has seen a gradual transition from large, completely radiation-hardened spacecraft electronics to smaller spacecraft that incorporate more commercial components for higher performance. Designers for these smaller spacecraft systems face the challenge of building reliable systems that could have both radiation-hardened and commercial components on the same system while incorporating fault-tolerant computing techniques. Frequently, designers are pressured with impending deadlines and, in an effort to reduce budget, accept having more commercial parts and designate lower requirements for assessing reliability of the design. This paper presents a new methodology for estimating reliability of space computers for small satellites from the system-level perspective, especially in scenarios where funding, time, or experience for radiation testing are scarce. These computed values can then be used to build a first-order estimate on how well the system performs given specific mission-environment conditions. These measures can be used to assist in making component or device selections by comparing the reliability of the same design with certain components replaced, comparing the reliability of different space computers, and comparing hardware and software fault tolerance within the board design.