The millions of tons of water ice is considered to be the most important resource on the moon. Harvesting water ice from lunar regolith requires a dedicated thermal management system (TMS) since (1) it requires very high thermal energy input to sublimate ice into vapor (i.e., volatile) and (2) capturing these volatile in the near-vacuum environment also needs significant cooling capacity. Advanced Cooling Technologies, Inc (ACT) in collaboration with Honeybee Robotics (HBR) is developing a well-engineered TMS for Lunar ice mining vehicles that are powered by MMRTG. The TMS can strategically and directly use the waste heat of nuclear power sources to extract water vapor from icy-soil on the moon and use cold environmental temperature as the heat sink to collect volatile within a cold trap container. This will enable ice harvesting with optimized consumption of electricity. In Phase I, ACT successfully developed and demonstrated two key thermal features of the proposed TMS. They are:
A preliminary full-scale TMS for a mining vehicle that can potentially meet NASA‘s requirements was designed and analyzed. In Phase II, ACT/HBR team will further mature the proposed TMS for Lunar Ice Miners. The efforts include optimization of all thermal components and development and validation of a numerical model to simulate the ice mining operation in relevant environmental conditions. An end-to-end demonstration system will be set-up and tested in a Lunar environmental chamber. A detailed design of full-scale TMS with optimized SWaP will be developed and reported by the end of the Phase II program.
The thermal management technology for a nuclear-based Lunar Ice Mining vehicle can immediately benefit Lunar In-situ Resource Utilization (ISRU) to harvest water on the moon. Water can be further processed to product Oxygen for life support and/or converted into LH2 and LO2 for spacecraft and satellite refueling. The technology can be useful to harvest water on other planetary bodies such as Mars and Asteroids.
The radioisotope power source that the TMS using may limit its potential in non-NASA applications. However, some components of the overall system may have market potential in foreseen lunar economy. For example: the switchable cold trap using no electricity and moving parts could be an essential ice storage device to support daily human activities on moon (e.g. lunar hotels, fueling station etc.).