Model and Testing Based Assurance of COTS Systems in Space Radiation Environments

The use of COTS (Commercial Off-The-Shelf) parts in space for electronics is increasingly becoming a significant enabler for many capabilities during a mission. This STTR project will provide a better understanding of the feasibility of COTS electronics for High Performance Computing (HPC) in space environments which are already heavily shielded. This STTR team (Alphacore + Vanderbilt University) proposes innovative strategies, based on a complete system analysis of HPC COTS that include, but are not limited to, identifying the vulnerable aspects of COTS-based HPC systems, failure modes and their propagation through the system, as well as selected parts radiation testing, to mitigate radiation induced impacts to potential HPC systems in those highly shielded space environments, such as manned missions and human habitats. nbsp;Thisnbsp;proposal aimsnbsp;tonbsp;(i)nbsp;evaluate radiation performance of sub-systems of an HPC system, (ii) develop mitigation techniques for each sub-system, and (iii) determine if NASA specs for space deployment can be met by the redesigned system using COTS components.nbsp;Thenbsp;radiationnbsp;effectsnbsp;modelnbsp;has two aspects: systems modeling language (SysML), and goal structuring notation (GSN), from which it can produce reliability objects for evaluating mission reliability of spacecraft: discrete Bayesian Nets (BN) and Fault Trees (FT).nbsp;nbsp;Usingnbsp;SysML, the target system is modeled via functional decomposition diagrams, architectural diagrams via block diagram models, fault propagation diagrams, which constitute a complete description of a spacecraft (or subsystem) with multiple functions. GSN is used to create a visual argument structure highlighting goals and strategiesnbsp;tonbsp;achieve required top-level function in given space environment for mission life. These goals and strategies are supported by solutionsnbsp;such asnbsp;radiation testing or mitigation strategies.nbsp;The methods will be extensively verified and validated by multiple irradiation tests (neutron, proton, alpha).nbsp;nbsp;