A TOOL FOR THE DESIGN OF SAFETY-CRITICAL SPACE CREW SURVIVAL SYSTEMS

This effort focuses on the development tool, which evaluates the safety-critical requirements of future HEDS program requirements. The software will enhance the design and analysis of space systems with the objective of enhancing their safety-critical success. Results from this software will provide the needed evidence to quantify the level of risk in software intensive systems. This tool uses failure mode effects analysis (FEMA), critical items list (CIL) and other intelligent and adaptive techniques to link undesired system events to their mitigating requirements, ultimately tracing to design and implementation. Undesired system events are described in the form of linguistic inference flow charts, such as fault trees and Petri-nets. Strategies to automatically translate linguistic inference flow charts into extended logic equations, and methods for verifying software systems safety-critical or mission-critical requirements are implemented. Also, where appropriate, subsystems are designed with the use of adaptive models, with the objective of enforcing safety or mission-critical requirements at subsystem interfaces. Also, the input of data or the transfer of output data to other software tools is automated. Interfaces for interchange of data, in software and hardware modes are carefully integrated, so the possibility of sharing of capabilities between models can be readily executed.