Environmental analysis of nanorovers in a swarm for lunar scientific missions

Abstract

Deep space missions are exposed to a broad range of temperatures and extremely high doses of radiation when compared to Earth bound space missions. Although standard passive and active strategies have been developed to protect spacecraft subsystems from fatal levels of radiation and unacceptable temperature levels inside the spacecraft, environmental analysis is a non-linear discipline which changes from project to project and therefore needs to be analyzed independently. Specially, taking into account the singular features which characterize each space mission. On the other hand. given that every kilogram launched beyond Earths orbit has signicant associated costs, space systems miniaturization has become a necessity with increasing popularity, which has driven the recent trend in the enhancement of this technology. These small complex systems need to be precisely simulated and verified with realistic simulations and experimental tests so that in an unexpected environmental situation, the risk of a total mission failure is reduced to the minimum. To accomplish mission requirements in terms of cost, mass and energy utilization for miniature spacecraft, passive thermal control systems (PTCS) are sought. In this project, Lunar Zebro, miniature space exploration surface vehicles will be connected together in a network, analyzing data from multiple nodes using interferometry; acting all together as a single dish. After introducing and analyzing the technological goals and objectives of this mission, the focus shifts into the environmental analysis of a single rover from this swarm. Its thermal behaviour is addressed in all mission phases, beginning from its performance on ground through to the Moon's surface, taking into account different possible scenarios. To do so, an own program is created (in MATLAB), in which an easy-to-apply and computationally efficient Ray Method is implemented. Among other applications, Visual Factors between the various faces of the rover and different heat sources (e.g. the Sun or Moon albedo) are computed using that methodology, which is explained in a step-by-step guide to be applied in any other software for other missions. To validate the model's accuracy and enhance the rover's thermal scope of knowledge, results will be compared to those obtained from ANSYS, a dedicated program for thermal applications. Recommendations for implementing the thermal analysis, together with limitations and future improvements of the method are also addressed. On the other hand, to get the complete overview of the environmental analysis of the mission, radiation issues are analyzed as well, taking into account the worst possible scenario. Outputs coming from this analysis will determine what is the optimal solution for protecting the rover. Finally, conclusions and future work to do in this mission are covered.