ECSS E 10-04 v0.10 - European Cooperation on Space Standardization ...

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<strong>ECSS</strong>-E-<strong>10</strong>-<strong>04</strong>B (draft v0.<strong>10</strong>) 13/03/2008
Space Environment
NOTE The translation of the orbit locations eastward in longitude 0,3°
per year since 1960 prior to accessing the models provides a
first approximation to this drift. [RD.14]
9.2.1.2. Electron fluxes in geostationary orbits
a. For electron fluxes in geostationary orbits (± 500 km altitude) the standard model for Earth
radiation belt energetic electrons shall be the IGE 2006 average model (previously called
POLE [RN.13] and Annex B.2).
b. For conservative analysis, the upper case model shall be used.
NOTE Models for other orbits are available, more information on
these models is given in Annex I.
9.2.1.3. Internal charging analyses
For internal charging analyses, the FLUMIC V3 model [RN.14] as described in Annex B.3 or,
for geostationary orbits, the NASA worst case model (Annex B.4) shall be used throughout the
mission and the highest fluxes reported by the model used.
NOTE These electron belt models are also appropriate for short-term
(from 1 day to 1 month) worst-case cumulative radiation effect
analyses.
9.2.2. Solar particle event models
a. Proton fluence from Solar Particle Events integrated over mission durations (of 1 year or
more) shall be derived using the ESP model described in Annex B.5.
b. For mission durations shorter than 1 year, the fluences for one year shall be used [RN.15].
NOTE For mission durations shorter than 1 year, this will result in a
conservative fluence estimate.
c. When using the model to calculate fluences for mission durations longer than 1 solar cycle
(11 years), the model shall be used with the total number of years of high solar activity during
the mission.
NOTE In cases where the instantaneous solar proton flux is required
or as a function of time during an event, there are several large
events that have been measured, their spectral fits are provided
in Annex I.2.3
d. For interplanetary missions, the results of the solar particle models shall be scaled by a factor
calculated as the mean value over the mission of: r -2 for r1AU, where r is in unit of AU.
NOTE Beyond 1 AU using a factor of 1 corresponds to a conservative
estimate of the maximum coefficient recommended in [RN.17].
e. For ions other than protons, either: the CREME96 model [RN.18] (only available online) or
Table B.7, Table B.8, and Table B.9 shall be used.
f. In Table B.7, Table B.8, and Table B.9 all ions shall be treated as fully ionised for geomagnetic
shielding calculations.
NOTE Standard solar particle event models do not include electrons.
These electrons can be significant for certain applications and
effects like internal charging. Information on typical electron
fluxes during solar particle events is given in [RD.15],
[RD.16].
9.2.2.1. Directionality
a. Fluxes and fluences of solar energetic particles shall be assumed to be isotropic.
NOTE Anisotropic distributions do exist in near-Earth space due to
geomagnetic shielding (see subclause 9.2.4) and in the early