The Van Allen radiation belts consist of energetic electrons and ions at energies above 100 keV trapped by the Earth’s magnetic field. These very energetic particles are harmful to satellite electronics and humans in space. In particular, relativistic electrons are responsible for the deep dielectric charging in sensitive electronic components and cause frequent satellite failures and operational problems. Multiple satellite measurements provide a vast amount of data that allows us to understand the competing acceleration and loss processes in the radiation belts and to develop accurate specifications of the space radiation environment for satellite engineers and operators. During this recent decade, we have discovered a number of critical acceleration and loss mechanisms for radiation belts electrons, and recent observations from the Van Allen Probes mission presented us with new questions. The observations of the unusual storage ring event and modeling of the unusual three-zone structure of the belts are performed and discussed.