This technology has implications beyond lunar vehicles, in broader applications of heat management in spacecraft
Astronauts traveling on the lunar surface in a vehicle face not only the dangers of zero gravity and a possible fall into a crater, but also drastic temperature fluctuations. The lunar climate ranges from a scorching high of 127°C to a bone-chilling low of -173°C.
The next lunar missions will need reliable machines that can operate in these harsh conditions. Recognizing the need for durable machines for continued lunar exploration, a team from Nagoya University in Japan has developed a thermal switch device designed to improve the robustness of lunar vehicles and extend their operational life.
"Heat switch technology that can switch between heat dissipation during the day and insulation at night is essential for long-term exploration of the moon," said lead researcher Mashito Nishikawara. "During the day, the lunar rover is active, and the electronic equipment produces heat. Since there is no air in space, the heat produced by the electronics must be actively cooled and dissipated. On the other hand, on very cold nights, the electronics must be isolated from the outside environment so that they don't get too cold."
Current devices tend to rely on passive heaters or valves connected to heat pipes in a loop for insulation at night. But expensive heaters and passive valves can increase the flow velocity of fluids, causing a pressure drop that can affect the efficiency of heat transfer. The technology developed by Nishikawara's team offers a golden path. With a lower pressure drop than passive valves and lower energy consumption than heaters, it maintains heat at night without compromising cooling performance during the day.
The heat control device the team developed combines a looped heat pipe with an electro-hydrodynamic pump. During the day, the pump is inactive, allowing the heat pipe to operate normally. In lunar vehicles, the heat pipe uses a coolant that cycles between the vapor and liquid states. When the device heats up, the coolant in the evaporator evaporates, releasing heat through the vehicle's radiator. The vapor is then compressed back into a liquid, which returns to the vapor to absorb heat again. This cycle is driven by capillary forces in the vapor, so it is energetically efficient.
At night, the pump exerts pressure that opposes the flow in the heat pipe, stopping the movement of the coolant. The electronics are completely isolated from the cold night environment with minimal use of electricity. The team's research included choosing the shape of the pump's electrodes, designing the device, evaluating performance and a demonstration experiment to stop the heat pipe operation using the pump. The results showed that the electricity consumption at night was almost zero.
"This groundbreaking approach not only ensures the vehicle's survival in extreme temperatures, but also reduces energy expenditure, a critical consideration in the resource-limited lunar environment," Nishikawara said. "It lays the foundation for potential integration in future lunar missions, and contributes to the realization of continuous lunar exploration activity."
This technology has implications beyond lunar vehicles, in broader applications of heat management in spacecraft. The integration of electro-hydrodynamic technology in thermal flow control systems can improve the efficiency of heat transfer and reduce operational difficulties. In the future, technology could play an important role in space exploration.
Revolutionary Rover_H
One response
The translation is almost readable. Recommend linguistic editing