Energetic Particles, Ionizing Radiation Effects, and Impacts to Human and Robotic Spaceflight

Space is a harsh environment and space radiation is one of the principle risks to space exploration, whether that exploration is by robots or by humans. In this talk, we provide an overview of the sources of space radiation, their effects, and efforts to understand, predict, and mitigate their risks. We begin with a summary of the principles of ionizing radiation from energetic particles. We next present an outline of the various sources of energetic particles, including the slowly varying component of galactic cosmic rays (GCR), the episodic, explosive component of solar particle events (SPE), and the trapped energetic particles that surround Earth in the Van Allen radiation belts. We discuss next the consequences and effects of these various components of ionizing radiation, and how each pose varying levels and types of risk to satellites and humans in different locations, whether it is airline crews and passengers on high altitude polar flights, the International Space Science in low-Earth orbit, GPS satellites in medium-Earth orbit, or robotic or human missions in deep space orbits to various exploration destinations throughout the solar systems (e.g., Moon, Mars, asteriods, etc.). Finally, we discuss efforts underway to characterize and predict both the slowly varying ionizing radiation "climate" as well as the impulsive "weather" in space.