New Findings, New Enigmas: NASA’s Van Allen Probes Begin their Exploration of the Radiation Belts

Mission overview: two spacecraft that target key radiation belt regions with variable spacing 2 identically-instrumented spacecraft for space/time separation. Spacecraft lap twice per quadrant (4-5 laps/year) for simultaneous observations over a range of s/c separations. 600 km perigee to 5.8 RE geocentric apogee for full radiation belts sampling. Orbital cadences (9 hr) faster than relevant magnetic storm time scales. 2-year mission for precession to all local time positions and interaction regions. Low inclination (10°) to access all magnetically trapped particles Sunward spin axis for full particle pitch angle and dawn-dusk electric field sampling. Space Weather broadcast Sun

Intensities of Earth’s dynamic radiation belts The Van Allen Probes Mission Objective is Important and its Impacts are Broad Objective: Provide understanding, ideally to the point of predictability, of how populations of relativistic electrons and penetrating ions in space form or change in response to variable inputs of energy from the Sun. Impacts: Understand fundamental radiation processes operating throughout the universe. Understand Earth’s radiation belts and related regions that pose hazards to human and robotic explorers. Resolve decades-old scientific mysteries of how these particles become energized to such high levels. 5.0- 3 Intensities of Earth’s dynamic radiation belts

Today’s Panel Members Daniel Baker Craig Kletzing Joseph Mazur Principal Investigator, Van Allen Probes Relativistic Electron Proton Telescope (REPT); part of the Energetic Particle, Composition, and Thermal Plasma Suite Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder, Colorado, USA Craig Kletzing Principal Investigator, Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) Department of Physics and Astronomy at the University of Iowa, Iowa City, Iowa, USA Joseph Mazur Principal Investigator, Van Allen Probes Relativistic Proton Spectrometer (RPS) Aerospace Corporation, Chantilly, Virginia, USA Unprecedented instrumentation making measurements in the heart of the radiation belts ECT/REPT RPS EMFISIS Search Coil EFW Spin Plane Wire Boom EFW Axial Boom EMFISIS Magnetometer