SPENVIS is a WWW-based instrument intended to facilitate the use of models of the spatial environment in a consistent and structured way. The model packages, that are available for Jupiter are briefly described below:

• coordinate generators
• radiation sources and effects
• spacecraft charging
• miscellaneous
• ECSS space environment standard

Coordinate generators

Most of the models related to Jupiter that are implemented in SPENVIS require as input a set of point on a spacecraft trajectory. These sets of points are produced by the orbit generator. In general, the orbit generator has to be used before the models themselves can be accessed. SPENVIS Is able to detect whether a spacecraft trajectory has been generated: if this is not the case, the system will issue an error message and prompt the user to run the orbit generator 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.

Once a trajectory 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 generator, all outputs previously obtained with models 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

For a spacecraft trajectory, a suite of radiation source and effects models is available:

• radiation sources:
  • trapped particle fluxes are calculated for the mission segment and accumulated into segment and mission fluences.
  • solar proton fluences are predicted for the total mission duration.
• radiation effects:
  • Damage-equivalent electron fluences for different types of solar cells can be evaluated with (EQFLUX), or with a NIEL based method (MC-SCREAM).
  • 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).
  • With the geometry definition tool a simple geometric representation of a spacecraft can be generated in GDML format, for use with SSAT.
  • The Sector Shielding Analysis Tool (SSAT) generates a shielding distribution from a GDML file supplied by the user of produced by the geometry definition tool. The shielding distribution can be used as input for the ionising or non-ionising dose models.
  • The Multi-Layered Shielding Simulation tool allows the definition of a multi-layered, one-dimensional shield and incident particle source, and using the Geant4 toolkit simulates radiation transport through the geometry, treating electromagnetic and nuclear interactions.
  • The Geant4-based Microdosimetry Analysis Tool (GEMAT) is a computer code to study microdosimetry effects of space radiation on micro-electronics and micro-sensors.
  • The CREME programme suite provides LET spectra of cosmic ray particles, and estimates single-event upset rates in micro-electronics.

JOREM

In the framework of the ESA project JOREM (Contract No 21290/08/NL/AT)—Jupiter Radiation Environment and Effects Models and Mitigation, a number of new models and tools for the Jovian environment and its effects have been developed:

• JOSE: models for the trapped proton, electron and selected ion environment;
• plasma models;
• SHIELDOSE-2 extension;
• an extended version of Planetocosmics for the Galilean moons;
• a genetic algorithm radiation shield optimiser
• a tool to upload and convert spacecraft trajectory files.

Spacecraft charging

(To be completed)

Miscellaneous

This package includes a number of models and tool which are not covered by the other packages:

• calculation of electromagnetic radiation incident on an oriented surface of a spacecraft;

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.