The Near-Earth Space Radiation for Electronics

The space radiation environment can have serious effects on spacecraft electronics. For example, accumulated damage from electron and proton exposure will limit system endurance. Transient effects from individual high-energy protons or cosmic rays can disrupt system operation, perhaps irreversibly. Of particular importance in assessing the impact of the space radiation on electronic devices are the limits in shielding effectiveness for high-energy electrons, protons, and cosmic rays. Thus, the internal spacecraft radiation envhmment is defined by particle transport through the spacecraft structure and, when necessary, shieldmg added to protect sensitive electronic pieceparts. Important effects on the internal electronics are performance degradation resulting from energy deposition by accumulated ionization in the semiconductor materials (total ionizing dose TID); accumulated atomic dqlacement damage in the crystal semiconductors by high-energy protons (&placement damage); and transient effects resulting from the ionization tracks from the interaction of a single cosmic ray or high-energy proton (single event effects SEE). Therefore, of particular interest for effects on the internal electronics are the total electron and proton exposure (i.e., fluence) and timedependent rate of high-energy protons and cosmic rays (i.e., flux.).