Modeling of the Earth's radiation belts

Satellites are continuously subject to radiation stress in orbit that may damage electronic components. In addition, this hostile environment is very variable. Its dynamics are characterized by time scales ranging from a few minutes to one solar cycle (11 years).

copyright © ONERA 2006 - Tous droits réservés Enveloppe limite externe des ceintures de radiation, modélisées par le code Salammbô. Les ellipses sont des orbites de satellites. Grande orbite verte  : géostationnaire, orbite orange : GPS, orbite jaune près de la Terre : satellite d'observation argentin SAC-C, orbite verte très excentrée :satellite japonais
copyright © ONERA 2006 - All rights reserved
Outside boundary envelope of the radiation belts, modeled by the Salammbô code. The ellipses are satellite orbits.
Large green orbit: geostationary; orange orbit: GPS; yellow orbit near Earth: Argentine SAC-C observation satellite; very eccentric green orbit: Japanese MDS1 "technological" experiment satellite.


Satellite designers and operators need to be able to reproduce the distributions of ionizing particles* in space at any given time. This gives them precious help in defining the specification models of future satellites as well as diagnostic tools for anomalies in flight.

It is to this end that the Craterre project financed by the CNES has been implemented by Onera. This project includes three avenues of research:

  • processing of in-flight measurements and the setup of a virtual observatory [ipsat]
  • physical modeling of the radiation belts
  • development of an in-flight measurement assimilation tool for defining a specification model of the ionizing radiations related to the radiation belts in space

Reconstruction 3D des ceintures de radiation de la terre
3D reconstruction of the Earth's radiation belts

Author: Sébastien Bourdarie,
Scientist in Onera's Space Environment Department [DESP]


  • *Ionizing particles
    Ionizing particles are particles that produce ionization in the matter they pass through. When these particles have sufficiently high energy levels, they tear off one or more electrons from the atoms they encounter, making them into positive ions.
    Satellites may be subject to high flows of ionizing particles (coming from the sun or trapped in the radiation belts), that may seriously damage the onboard electronics.
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