Design and Test of a Prototype of Soil Sampler Equipped on a Rover for Mars Exploration

This study deals with the design and the experimental test of a prototype of soil sampler to be equipped on team DIANA’s rover ARDITO, a vehicle designed for competitions related to human assistance during Mars exploration. The project was carried out in collaboration with team DIANA, a student team from Politecnico di Torino involved in the design and production of rovers, with the purpose of joining the World Rover Challenge series. A brief analysis of the main systems available for Earth and Mars soil sampling was first carried out to quantify the parameters mainly affecting the quality of the sampling and the effective feasibility on Mars soil. Then, the design of the soil sampler prototype was described in its four main components: sampler, percussion system, lifting system and control system. Afterwards, the development and results of an extensive experimental campaigns was analysed. All test campaigns were performed at MastrLAB of Department of Structural, Building and Geotechnical Engineering (DISEG) of Politecnico di Torino. The aim of the different tests concerned a preliminary evaluation of the performances and operational limits of the prototype. Some tests were also performed on two parts of the sampler sub-system: the holder and the catcher, to study the influence of the type of tested soil by changing the diameter of the holder and the stiffness of the catcher. Basing on these outcomes, the soil sampler prototype was tested, evaluating the correlation between the soil penetration and the number of blows required. All the experimental investigations were performed on a test bench specifically built for the soil sampler prototype, and different soils grading and mixtures were employed, in loose and compacted conditions. A compaction procedure for each soil was also proposed together with some safety aspects concerning the use and maintenance of the prototype. The results of the tests campaign on the soil sampler prototype revealed that the soil sampling was not performed due to the undersized internal diameter of the advanced shoe. The preliminary results concerning the soil penetration provided positive outcomes on the possibility of correlating the number of blows with the compaction degree of different soils.