SPENVIS is a WWW-based instrument intended to facilitate the use of models of
the spatial environment in a consistent and structured way. The system breaks
down into a number of model packages, which are briefly described below:
Coordinate generators
Most of the models implemented in SPENVIS require as input a set of point on a
spacecraft trajectory or a user-defined set of geographic points. These sets of
points are produced by two tools: the
orbit generator and the
coordinate grid generator. In general,
one of these tools has to be used before the models themselves can be accessed.
SPENVIS Is able to detect whether a spacecraft trajectory or a coordinate grid
has been generated: if this is not the case, the system will issue an error
message and prompt the user to run the orbit or coordinate grid tool, after
which the model in question can be run.
In addition, the model menu on the packages page will adapt automatically
to the selection of trajectories or grids.
Once a trajectory or a coordinate grid has been generated, it can be used by
different models. This means that, in the context of a given
project, it is not
necessary to generate coordinates for each model separately.
Warning! When running the orbit or grid generator, all outputs
previously obtained with models that use the respective coordinate tool, are
deleted. This is to ensure consistency between results, and to avoid errors in
the plotting routines that produce the graphical output. The input parameters
for the models are not deleted, so that they can be run again in the same way.
Radiation sources and effects
If the currently selected coordinate system is a grid,
trapped particle models
can be evaluated and visualised over the grid.
In addition, these models can be run over a grid of
magnetic coordinates from the
miscellaneous model menu.
For a spacecraft trajectory, a suite of radiation source and effects
models is available:
- radiation sources:
- radiation effects:
- Damage-equivalent electron fluences for
different types of solar cells can be evaluated with EQFLUX.
- Ionising dose behind three types of Al shielding
(SHIELDOSE).
- Device degradation such as charge
transfer efficiency loss in CCDs is estimated by calculating
damage-equivalent proton fluences and non-ionising energy loss
(NIEL).
- Single-event upset rates in
micro-electronic devices for short-term fluxes.
- Single-event upsets in
micro-electronic devices for long-term fluences.
The
combined run feature allows the selection of a
number of models for a consecutive run without navigation between models. This
feature facilitates investigating the influence of orbital or radiation model
parameters on the radiation effects.
This feature is available for
advanced users
only.
Spacecraft charging
SPENVIS Incorporates a number of utilities developed for
ESA/ESTEC to solve various
problems associated with
spacecraft/plasma interactions.
The DICTAT programme calculates the electron
current that passes through a conductive shield
and becomes deposited inside a dielectric. From the deposited current, the
maximum electric field within the dielectric is found. This field is compared
with the breakdown field for that dielectric to see if the material is at risk
of an electrostatic discharge.
Three modules of the programme suite
ESPIRE have been
implemented in SPENVIS:
- EQUIPOT: computes the equilibrium potential of
a surface using a simple model of differential material charging;
- SOLARC: provides an estimate of the current
collection and power loss that would be experienced by a solar array in the low
Earth orbit plasma environment.
- LEOPOLD: a simple menu driven code that allows
the rapid determination of the principal parameters that characterise the low
Earth and polar orbital environments;
In addition, a collection of satellite data of
charging events
is available from the
GORIZONT/ADIPE and
CRRES/LEPA missions.
Atmosphere and ionosphere
SPENVIS implements a number of reference
atmosphere and ionosphere models
in two applications:
Magnetic field
SPENVIS implements some of the most currently used
magnetic field models
in three applications:
Meteoroids and debris
The following models are being included in SPENVIS: NASA90 and MASTER for
orbital debris, the Grün meteoroid model, and wall penetration models.
Both natural
meteoroids and man-made space debris particles represent a serious hazard to
space vehicles in orbit around the Earth. Nearly all meteoroids originate from
comets or asteroids, and are generally distributed isotropically (termed
`sporadic' meteors), except those that retain their parent body orbit, which
are termed `meteor streams'. The total meteoroid environment is thus comprised
of the average of the sporadic meteors together with the yearly average of
meteor streams. Also co-existent with the natural particle flux are space
debris particles, most of which are in high-inclination orbits, and consist of
spent rocket stages, inactive payloads, debris from exploded satellites, etc.
The meteoroid and debris models included in SPENVIS are:
For the particle/wall interaction two models are included in SPENVIS that are based on:
Miscellaneous
This package includes a number of models and tools that are not covered by the
other packages:
Geant4 tools
This package includes a number of models and tools that are using the Geant4 toolkit:
ECSS Space Environment Standard
The SPENVIS system
contains a copy
of the European Cooperation for Space
Standardization (ECSS) standard on space environment.
The official site
is maintained by ESTEC.
Links are available from the help pages to the relevant ECSS standards, and
from the ECSS pages to the SPENVIS model and help pages.
Planetary environment
SPENVIS includes models
related to the space environment of other planets: In order to
access those models, the user has first to switch to
another planet in the coordinate generator package.
Last update: Fri, 20 Apr 2018