Safe or emergency fault protection approaches for spacecraft

This paper gives a description of a simple and robust approach to the fault protection of spacecraft. Often on modem spacecraft, fairly sophisticated methods of fault protection are developed. These fault protection systems, while having excellent capabilities to keep spacecraft safe with a minimum of ground interaction, can often become a risk to the spacecraft in their own right. One approach to mitigate these kinds of risks is to have a simple and easily verifiable hardware based fault protection system. Our approach utilizes existing avionics hardware, with a simplified command and control architecture to provide a robust way of safing a spacecraft. Safing a spacecraft is defined herein to mean orientating the spacecraft in a power positive orientation while controlling all spacecraft life functions using minimal power and hardware. This Emergency Mode Controller was completed and tested at Ball Aerospace & Technologies Corp., and will be used on future Ball spacecraft in LEO, GEO, and Deep Space applications for customers in the Defense and NASA communities.