Exploration of the Moon presents unique challenges, particularly in terms of temperature control for lunar vehicles. The innovative heat-switch device developed by researchers from Nagoya University, in collaboration with the Japan Aerospace Exploration Agency, represents a significant advancement in this area. The device promises to extend the operational lifespan of lunar-roving vehicles in the harsh Moon climate.
Published in the journal Applied Thermal Engineering, their work introduces a system that can adapt to the Moon’s extreme temperature fluctuations, which range from 127°C (260°F) during the lunar day to -173°C (-280°F) at night.
“Heat-switch technology that can switch between daytime heat dissipation and nighttime insulation is essential for long-term lunar exploration,” said lead researcher Masahito Nishikawara. “During the day, the lunar rover is active, and the electronic equipment generates heat. Since there is no air in space, the heat generated by the electronics must be actively cooled and dissipated. On the other hand, during extremely cold nights, electronics must be insulated from the outside environment so that they don’t get too cold.”
The current methods of nighttime insulation for devices often come with drawbacks such as high cost or reduced efficiency.
Nishikawara’s team has developed a technology that provides a solution with lower power consumption and less impact on heat transfer efficiency. Their thermal control device combines a loop heat pipe with an electrohydrodynamic pump, offering effective nighttime insulation without compromising daytime cooling performance.
The device uses a refrigerant that cycles between vapor and liquid states. During the day, the EHD pump is inactive, allowing the loop heat pipe to operate as usual. At night, the EHD pump stops the movement of the refrigerant, providing complete insulation for the electronics with minimal electricity use.
The research and demonstration tests showed almost zero power consumption at night, making this technology a highly efficient and cost-effective solution for nighttime insulation.
“This groundbreaking approach not only ensures the rover’s survival in extreme temperatures but also minimizes energy expenditure, a critical consideration in the resource-constrained lunar environment,” Nishikawara said. “It lays the foundation for potential integration into future lunar missions, contributing to the realization of sustained lunar exploration efforts.”
The potential of this technology reaches far beyond lunar rovers to encompass broader applications in spacecraft thermal management. The integration of EHD technology into thermal fluid control systems holds the promise of enhancing heat transfer efficiency and addressing operational challenges. This breakthrough could play a pivotal role in advancing space exploration.
The creation of this heat-switch device signifies a significant achievement in the advancement of technology for prolonged lunar missions and other space exploration initiatives. Consequently, lunar rovers and other spacecraft are poised to be better equipped to function effectively in the formidable realms of space in the future.
Journal reference:
- Masahito Nishikawara, Takeshi Miyakita, Genki Seshimo, Hiroshi Yokoyama, Hideki Yanada. Demonstration of heat switch function of loop heat pipe controlled by electrohydrodynamic conduction pump. Applied Thermal Engineering, 2024; DOI: 10.1016/j.applthermaleng.2024.123428