Risk management for micro-satellite design

It is shown how the methods of risk analysis have been used in the University of Rome micro-satellite program. One of the driving research topics related to this program is the reduction of cost in building spacecraft. The probability risk analysis techniques seem to be a powerful tool in the field of micro-satellites design, to outline possible faults. Innovation and limited budget force the designer to move in a very “risky” environment and can be faced with an as rigorous as possible decision making method. In our project, cost reduction is often attained relying on commercial, not space-rated components, which of course increases risk. This is why the design process should be led by the careful analysis of the risk associated with the selection of components and construction techniques. In standard applications risk can be evaluated from reliability data obtained in previous and well known similar applications. In our case, for many components, there is a lack of reliability data, due to the obvious missing experience when dealing with not yet space qualified, or even never flown before components. This lack is overcome using numerical simulations and practical engineering considerations, but does not allow a rigorous reliability assessment. A simple qualitative analysis is used to rank priorities among subsystems and allocate economic resources and development efforts. The main risk source is space radiation effect on CMOS electronic components. Therefore, development resources are directed to radiation effect mitigation. A procedure is proposed to lower risk without using space rated components.