Speaker
Dr
Pete Truscott
(Kallisto Consultancy Ltd)
Description
The Jovian radiation environment presents a severe threat to spacecraft operation due to the large magnetic field of Jupiter allowing it to stably trap charged particles, especially electrons, at higher energies and over greater distances than found in Earth’s Van Allen belts. As part of the ESA Laplace mission, an assessment is ongoing into the different hardening and alternative radiation mitigation strategies which may be implemented to reduce the threat from ionising and non-ionising cumulative dose, and spacecraft charging. Since a significant fraction of the Laplace spacecraft’s time within the Jovian magnetosphere will involve orbiting the moon Ganymede, the shielding offered by the intrinsic magnetic field of the moon, and physical shielding of the moon to the rotating plasmasphere should be assessed. Tracking particles within the complex rotating magnetic fields of Jupiter and Ganymede, and the probability of interactions with the moon’s surface is a non trivial calculation. Currently this can be achieved using the Geant4-based PLANETOCOSMICS-J (PCJ) model developed as part of the JORE2M2 Project, but the lengthy simulation times make it difficult to use this as an engineering tool to explore the influence of the moon for different mission and orbital scenarios.
The objectives of the work are to develop and validate a SPENVIS-based software tool to perform fast simulation of the radiation environment for orbits and spacecraft trajectories in the vicinity of Ganymede. This is to be based on a database of results from the PLANETOCOSMICS-J model for the transmitted fraction of electrons as a function of Ganymede longitude, latitude, altitude, electron energy and location of Ganymede within the Jovian magnetosphere. The Ganymede Radiation Environment Engineering Tool (GREET) will combine the transmission fraction with the JOSE electron environment model and orbital information to generate electron fluxes and energy spectra.
