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Description
Australia’s first Moon rover, Roo-ver, is scheduled to launch to the Moon later this decade where it will be remotely operated to explore the surface for a full lunar day (around 14 Earth days). Roo-ver is being designed, built and tested in Australia by the ELO2 Consortium as part of the Australian Space Agency’s Moon to Mars initiative. This project received grant funding from the Australian Government through the Australian Space Agency and EPE Oceania Pty Ltd. In preparation for its journey to the moon, one of the major challenges Roo-ver must overcome is surviving the harsh radiation environment of the lunar surface.
Swinburne University of Technology leads the radiation effects package for the ELO2 Consortium. This work outlines the development and assessment of the radiation exposure expected during the Roo-ver’s lunar surface operations using a custom-built Geant4 application. The Galactic Cosmic Ray (GCR) component of the radiation environment was calculated via SPENVIS for solar minimum conditions in interplanetary space using the ISO 15390 model, as recommended by the ECSS-E-ST-10-04C standard. Within Geant4, primary GCR particles were generated from a hemispherical surface and directed isotropically towards a flat volume representing the lunar surface. A high-fidelity Roo-ver CAD model was integrated within the Geant4 simulation using the publicly available CADMesh library. Additionally, the creation of secondary particles from the interaction of GCRs with the lunar surface, referred to as Backscattered Lunar Radiation (BLR), were simulated and tracked. The interactions of the primary GCR and secondary BLR particles within critical components of Roo-ver are simulated in Geant4 using the QBBC physics list with G4EMStandardPhysics_option4 activated. The results of this simulation study will allow for the prediction of key quantities such as particle flux, total ionising dose, and linear energy transfer (LET) within Roo-ver’s most susceptible components including the solar cells, navigational cameras and sensors, and on-board motor control electronics.