scope:

Abstract:

False star sightings by the Magellan star scanner during cruise to Venus prevented spacecraft attitude updates and occasionally caused false updates. Two causes were identified: 1) high energy solar protons sensed by the star scanner detector, and 2) quartz particles ejected from thermal blankets due to thermal shock. Selection of spacecraft sensors should consider all environmental effects. Consider the tendency of spacecraft materials to shed particles. System design must take into account the limitations of sensor and spacecraft material performance and show that the risk is acceptable.