We study planetary bodies and the processes that govern their formation, evolution, behavior, and potential for life, with a combined theoretical and experimental approach. We investigate the interaction of space plasmas with planetary atmospheres, surfaces, and interiors. We explore the internal structure, origin and evolution of planets, moons, comets and asteroids through observation, modeling, and sample analysis. We also develop high-sensitivity space-based instrumentation for a variety of scientific investigations, including particles, electromagnetic fields, and detection of complex, including biogenic, organics. SSL has led or played a major role in several planetary science missions going back to the dawn of the space age.