Modeling of the Space Environment
an abstract by Yue Fei
The effects of radiation belt particles on spacecraft are well known.
Electrons can produce charging which can induce electrostatic discharges;
protons can produce Single Event Effects in electronics. These two effects
are well correlated to the immediate environment, so they are also called
space weather effects. Moreover, electrons and protons induce total dose
effects which modify the characteristics of electronics, coatings and
optics onboard satellites. Therefore, the development of reliable radiation
belt models, either long-term or short-term, is essential in preventing
these effects.
Existing long-term models have to be updated because they were developed
at the beginning of the space age, when radiation belt dynamics was not
well understood. Updating these models is a complex process which involves:
- Good measurements, taken from different orbits.
- A physical understanding of the dynamics of the radiation
belt, and a physical
model to interpolate between measurements.
- Scientific satellites, with well-chosen orbits, to deliver
absolute calibration and
to make possible inter-calibration between measurements from different
satellites.
- Technology satellites, to make a relation between the environment
and its
effects. These satellites are essential for trying new technologies
and new
materials.
- Operational satellites, to measure long-term variations in
the environment, and for inter-calibration between scientific
and technology satellites.
A physical model of the radiation belt is very useful because it
can provide a better understanding of the variation in the environment
on both a short-term and a long-term basis; it can interpolate between
measurements to give global now casting of the radiation belt, and;
it increases the representativity of the data set. For example, a
3-D radiation belt model might use geosynchronous measurements to
build the entire electron radiation belt and compare it with orbital
measurements obtained by other satellites. |