The Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)) were designed to help us understand the sun’s influence on Earth and near-Earth space by studying the Earth’s radiation belts on various scales of space and time.

The instruments on NASA’s Living With a Star Program’s (LWS) Van Allen Probes will provide the measurements needed to characterize and quantify the plasma processes that produce very energetic ions and relativistic electrons. The Van Allen Probes are part of the broader LWS program whose missions were conceived to explore aspects of the connected sun-Earth system that directly affect life and society. Van Allen Probe instruments will measure the properties of charged particles that comprise the Earth’s radiation belts, the plasma waves that interact with them, the large-scale electric fields that transport them, and the particle-guiding magnetic field.

The two Van Allen Probe spacecraft have nearly identical eccentric orbits. The orbits cover the entire radiation belt region and the two spacecraft lap each other several times over the course of the mission. The Van Allen Probes in-situ measurements discriminate between spatial and temporal effects, and compare the effects of various proposed mechanisms for charged particle acceleration and loss.