Quick Facts: Van Allen Probes

The identical Van Allen Probes satellites

The identical Van Allen Probes follow similar orbits that take them through both the inner and outer radiation belts. The highly elliptical orbits range from a minimum altitude of approximately 373 miles (600 kilometers) to a maximum altitude of approximately 23,000 miles (37,000 kilometers). (Courtesy JHU/APL)

Mission Introduction

The Van Allen Probes mission, previously known as the Radiation Belt Storm Probes (RBSP) mission, is part of NASA’s Living With a Star Geospace program to explore fundamental processes that operate throughout the solar system, in particular those that generate hazardous space weather effects near the Earth and phenomena that could affect solar system exploration.

The Van Allen Probes are enabling us to understand the Sun’s influence on the Earth and near-Earth space by studying the planet’s radiation belts on various scales of space and time.

Understanding the radiation belt environment and its variability has extremely important practical applications in the areas of spacecraft operations, spacecraft system design, mission planning, and astronaut safety.

The mission’s science objectives are to:

  • Discover which processes, singly or in combination, accelerate and transport radiation belt electrons and ions and under what conditions
  • Understand and quantify the loss of radiation belt electrons and determine the balance between competing acceleration and loss processes
  • Understand how the radiation belts change in the context of geomagnetic storms

The instruments on the two Van Allen Probes spacecraft provide the measurements needed to characterize and quantify the processes that produce relativistic ions and electrons. They measure the properties of charged particles that comprise the Earth’s radiation belts and the plasma waves that interact with them, the large-scale electric fields that transport them, and the magnetic field that guides them.

LASP Roles

LASP provides:

  • The Digital Fields Board (DFB) for the Electric Field and Waves Suite (EFW)
  • The Relativistic Electron Proton Telescope (REPT) for the Energetic Particle, Composition, and Thermal Plasma Suite (ECT)
Van Allen Probes Electric Field and Waves instrument

The objectives of the Electric Fields and Waves instrument are to measure electric fields associated with a variety of mechanisms causing particle energization, scattering and transport in the inner magnetosphere. (Courtesy JHU/APL)

LASP Instruments

The Van Allen Probes Electric Field and Waves Suite (EFW) studies the electric fields in near-Earth space that energize radiation particles and modify the structure of the inner magnetosphere.

This investigation consists of a set of four spin-plane electric field (E-field) antennae and a set of two spin-axis stacer (tubular, extendable) booms. The investigation is providing an understanding of the electric fields associated with particle energization, scattering and transport, and the role of the large-scale convection electric field in modifying the structure of the inner magnetosphere.

The DFB provides the bulk of the signal processing for the EFW. It provides analog and digital filtering, digitizes electric and magnetic field signals, performs spectral and cross-spectral calculations, and performs on-board coordinate transformation of the electric fields into magnetic field-aligned coordinates

Van Allen Probes-EFW Science Investigation Objectives:

To measure electric fields associated with a variety of mechanisms causing particle energization, scattering and transport in the inner magnetosphere, including:

  • Energization by the large-scale convection E-field
  • Energization by substorm injection fronts propagating in from the magnetotail
  • Radial diffusion of energetic particles mediated by ultra-low frequency (ULF) magnetohydrodynamic (MHD) waves
  • Transport and energization by intense magnetosonic waves generated by interplanetary shock impacts upon the magnetosphere
  • Coherent and stochastic acceleration and scattering of particles by small-scale, large-amplitude plasma structures, turbulence and waves (electromagnetic and electrostatic ion cyclotron waves, kinetic Alfvén waves, solitary waves, electron phase space holes, zero frequency turbulence)
The REPT instrument flight model

This image displays a flight model of the Relativistic Electron Proton Telescope, which helps capture the most intense radiation belt events. (Courtesy UNH)

The Van Allen Probes Energetic Particle, Composition, and Thermal Plasma Suite (ECT) directly measures near-Earth space radiation particles to understand the physical processes that control the acceleration, global distribution, and variability of radiation belt electrons and ions.

REPT covers the challenging electron range of 4-10 MeV and proton energy range of 20-75 MeV to capture most intense events.

Van Allen Probes-ECT Science Investigation Objectives:

  • Determine the physical processes that produce radiation belt enhancements
  • Determine the dominant mechanisms for relativistic electron loss
  • Determine how the inner magnetospheric plasma environment controls radiation belt acceleration and loss
  • Develop empirical and physical models for understanding and predicting radiation belt space weather effects

Quick Facts

Launch date: August 30, 2012
Launch location: Kennedy Space Center, Cape Canaveral, Florida
Launch vehicle: Atlas V-401
Mission target: Earth orbit
Mission duration: 2 year primary mission; extended through 2019
Other organizations involved:

  • NASA Goddard Space Flight Center (GSFC)
  • University of California, Berkeley
  • Johns Hopkins University Applied Physics Laboratory
  • University of New Hampshire
  • University of Iowa
  • University of Minnesota
  • New Jersey Institute of Technology

Click on the image to view a PDF (646 KB) of Van Allen Probes FAQs.
Van Allen Probes (646 KB PDF)