Jul 17, 2010

Rover Thermal Analysis

Xavier Laurand, a Masters student at Cranfield University, is undertaking a Masters thesis project on the thermal design and analysis of the White Label Space moon rover under development for our mission in the Google Lunar X PRIZE (GLXP).

One of the major challenges on the moon is to deal with the wide range of surface temperatures that results from its lack of an atmosphere and its slow rotational speed. The extremely high infrared flux from the moon can be attributed the moon's surface properties, namely the low albedo, high absorbtivity and emissivity. Consequently the lunar regolith absorbs most of the sun's energy and reaches very high temperatures during the day. At night it emits a lot and cannot maintain its temperature for a long time. During cold periods, sufficient electric power is needed to maintain the electronics at a temperature high enough to survive. During high temperature periods, the radiators on the rover must be capable of rejecting enough heat to keep all electronic equipment within its functional limits. Even if the baseline mission requires operation only during the lunar day, the temperature range is extreme.

Xavier is using thermal analysis software based on the lumped parameter method to analyse the performance of the rover under its expected operating conditions. The picture below shows some of Xavier's analysis results for a non-flat terrain with high surface temperatures. His thermal analyses take into account both radiative and conductive effects.

An important thermal challenge of lunar surface missions is dealing with dust from the lunar regolith. Dust deposits can occur on the surfaces of the rover due to the landing, the natural deposition, meteorite impacts and roving. Since the thermal control subsystem can be impacted by these dust deposits (particularly on the radiator surfaces), Xavier is analysing their impacts and investigating design mitigation techniques.

Xavier is undertaking the MSc course in Astronautics and Space Engineering at Cranfield University. His project is being conducted in partnership with Tohoku University Space Robotics Lab, the lead partner for the team’s rover development. The lead thermal designer in White Label Space core engineering team, Martin Lemmen, is providing additional technical guidance for Xavier’s project.

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