A Wireless Lunar Sensor Node Powered by Temperature Gradients across the Device’s Surface

Miniature ballistically-deployed wireless sensor nodes can extend the exploration of rovers and landers to hard-to-reach or dangerous areas (e.g., rock piles, steep crater rims, etc.) on the Lunar surface. After deployment, multiple sensor nodes can collect simultaneous data from different positions, which aids in studying dynamic phenomena. To guarantee long-term operations, energy harvesting is crucial. When a miniature wireless sensor node is deployed on the Lunar surface, one side will face the sunlight and the opposite will be in shadow. The moon’s surface is essentially a vacuum, hence the temperature on the sunlit side is much higher than the shadowed side due to the lack of an atmosphere to block solar irradiation in the sunlit areas and block heat in the shadowed areas. This can form a large temperature gradient on the sensor node surface. In this paper, we study this in-situ energy harvesting approach using a custom thermopile that leverage the temperature gradient between the sunlit and shadowed sides of the sensor node’s body. The predicted sensor node’s surface temperature gradient is explored in simulation, and an over 100
^°
C temperature difference is observed. A custom-designed thermopile is integrated into the sensor node, and the energy harvesting performance is validated through lab experiments that demonstrate the level of energy that can be harvested through our custom-designed thermopile.