The main sources of energetic particles that are of concern to spacecraft designers are the following: (1) Protons and electrons trapped in the Van Allen belts (2) Heavy ions trapped in the magnetosphere, (3) Cosmic ray protons and heavy ions, and protons and heavy ions from solar flares. The levels of these sources are affected by the activity of the sun. There are also large variations in the levels of SEE inducing flux that a spacecraft encounters, depending on its trajectory through the radiation sources. Missions flying at Low Earth Orbits (LEOs), Highly Elliptical Orbits (HEOs), and Geostationary Orbits (GEOs), and Planetary and Interplanetary missions have unique requirements. The most effective means of reducing uncertainty factors and design margins in particle predictions is to define when and where the mission will fly. Also, the detailing of worst-case environmental conditions, systems critical to success, and the amount of shielding surrounding the SEE sensitive part(s) is established. Radiation Test Data/Facilities DIE & WAFER MEMORY SPECIALISTS Copyright 2000-2008 Die Delivery and Services