Speakers
Description
Led by the European Space Agency, the ExoMars mission will address the question of whether life has ever existed on Mars. The first part of the mission, the Trace Gas Orbiter, was launched in 2016. The second part, the Rosalind Franklin rover, will be Europe’s first rover on the surface of Mars. Its objective is to travel on the surface, collecting underground samples and analyzing them on a next-generation on-board laboratory.
MDA contributed to the mission by providing the locomotion sub-system, dubbed the Bogie Electro-Mechanical Assembly. BEMA includes all the components required for on-surface locomotion, and comprises the pivoting structure, legs, 6 flexible wheels as well as 18 rotary actuators that will enable all roving operations on the surface.
The environment on the Mars surface is unique, and predicting the thermal performance poses a real challenge. With an atmosphere approximately 170 times less dense than Earth and consisting mostly of Carbon Dioxide (CO2), temperatures oscillating between -140°C and 25°C, in addition to the occasional dust storms, there are few software tools which are able to reproduce the thermal environment in its entirety.
To predict the performance, MDA used SimCenter3D (SC3D). SC3D’s Space System Thermal module has been used for thermal analyses in the space environment for over 30 years, but the software also has complete CAD/CAE integration and full CFD capabilities. That allows modeling the radiation-driven space environment, but also the detailed fluid volume and convective heat exchanges to any level of detail. Using this software, the thermal design of the locomotion system could be established in order to maximize the operating time of the rover during the Martian day, with an effective heat-up in the morning, high heat rejection capabilities to increase roving time, as well as minimal heat losses overnight.
The components and final assembly were tested to simulate exposure to the Martian environment. Testing itself had a lot of challenges, as fully representing the Mars environment is not feasible with standard testing facilities. To be able to do that, MDA repurposed one of its thermal vacuum chambers to maintain a partial vacuum and a CO2 atmosphere. With this adapted test facility, MDA was able to perform life tests and fully qualify the assembly for its upcoming mission on Mars.
