Welcome to the web site of the ESA/ESTEC project
Energetic Electron Environment Models for MEO
, Contract No.21403/08/NL/JD .
It has become obvious that the space environment is a highly aggressive medium. Indeed, beyond the
natural protection provided by the Earth's atmosphere (magnetospheric shielding), various types of
radiations can be encountered (electron, proton, solar proton, cosmic rays, ?). Their
characteristics in terms of energy, nature, origins and distribution in space are extremely
variable and highly depend on the spacecraft orbit.
Previously, European programs have been concerned mainly, by LEO and GEO environments. Now,
with the new European navigation system (Galileo), efforts have to be concentrated on the study of the
Medium Earth Orbit (MEO) environment.
Traditionally, NASA AE8 model is used to predict electron fluxes. But, on the one hand, this static
model is based on data collected in the 60's and 70's so new updated data have to be integrated and
analysed, and on the other hand, more accurate models have to be developed to reduce margins of a
necessarily reliable system for a commercial service.
The MEO orbit corresponds to a rather severe environment as for electrons it corresponds to the core
of the outer belt. The environment is moreover extremely dynamic like at GEO, but with much higher
flux levels for the whole spectrum. It means that at least all the effects damaging satellites at GEO
are of great importance for MEO applications: dose, charging, backgrounds, etc?
For these applications, a better knowledge of the electron environment is needed in order to
decrease the margins and to anticipate in flight problems.
The main goal of this study is to produce new engineering models for electron environment taking into
account the following goals:
The dynamic nature of the outer electron belt,
The exploitation of new data: data from ESA monitor (SREM) and available data from European
or international monitors on others interesting orbits,
The model accuracy for Galileo orbit characteristics,
The implementation in engineering systems and tools.
The work will be performed by a consortium consisting of: