To develop European models for the radiation, plasma, microparticle, plume and atmosphere environments of Saturn and its moons within an extensible model framework applicable to all gas giant systems.

Background and context: Missions are being studied to the systems and moons of outer planets, including extended observation periods by local orbiters or possible landers, that require careful evaluation of the local radiation, plasma, microparticle, atmospheric and plume environment for design of both platform and science payload. Radiation impact potentially includes total cumulative doses, single event effects from short term enhancements and internal charging risk whilst plasma environments present risks of surface charging. Behaviour of the plasma environment and mechanisms for trapping, acceleration, losses for electrons and protons in the outer planet radiation belts are not very well known. Highly tilted global magnetic fields with respect to the planet rotation axis are believed to induce complex interactions with heliosphere. Of those planets in the solar system which possess significant magnetospheres, the Saturnian system is not as well characterised as Earth or Jupiter whilst not being described by models at all for Uranus and Neptune. Local (natural) microparticle environments are also important due to the large gravitational attraction of the gas giants and the potential for impact damage posing a risk to spacecraft.Justification of the activity:The Saturnian system and its moons each have their local and variable environments. These environments have been experimentally studied by missions such as Cassini, Pioneer 11 and Voyager 2. A dedicated NASA model (SATRAD) exists for the Saturnian system as well as similar models for Uranus (UMOD) and Neptune (NMOD). Relevant European model developments (such as JOSE, Salammbo, BAS project, JMEM) exist for the Earth an Jovian systems only. Thus far there is no coherent and complete European set of engineering models for the environments of the moons of these planets for future mission analysis purposes. Description of the technology to be developed:This activity will develop a flexible and easy-to-use environment model framework and related software for gas giant planet moon systems based on the wealth of data from visiting missions. The resulting model catalogue will be targetted at deriving specifications for future science mission engineering purposes. Within this activity, derived specific models shall be focused on the Saturnian system.This activity encompasses the following tasks: - Literature study, including scientific analyses and reports from other modelling activities.- Review of existing datasets and possible need for data (re) analysis (target engineering models). - Development of a comprehensive set of model framework for the systems and moons of the outer planets.- Validation of the model output against existing in situ and remote data, and comparison to other models. - Application of framework to derive models for mission scenarios to the Saturnian system and possible extension to other exploration scenarios from current ESA studies.- Integration of the new models in the ESA Space Environment Information System (SPENVIS)Software shall be delivered under an ESA Software Community Licence, so that any individuals or entities within ESA Member States can access to it and can provide update to the community of users.