Lunar Wireless Power Transfer Feasibility Study

Abstract

-This study examines the feasibility of a multi-kilowatt wireless radio frequency (RF) power system to transfer power between lunar base facilities. Initial analyses, show that wireless power transfer (WPT) systems can be more efficient and less expensive than traditional wired approaches for certain lunar and terrestrial applications. The study includes evaluations of the fundamental limitations of lunar WPT systems, the interrelationships of possible operational parameters, and a baseline design approach for a notionial system that could be used in the near future to power remote facilities at a lunar base. Our notional system includes state-of-the-art photovoltaics (PVs), high-efficiency microwave transmitters, low-mass large-aperture high-power transmit antennas, high-efficiency large-area rectenna receiving arrays, and reconfigurable DC combining circuitry. I. SummaryNASA has embarked on a bold mission to return to the moon and establish a permanent presence. A moon base will require a vast amount of resources that can be extracted from various locations. A key question is how to deliver power to facilities (load stations) distributed on the lunar service, possibly in places where there is little sunlight. Initially, the load stations are planned to be 0.5 to 2km away from mountain-tops where photovoltaic generation stations can be placed. Each site is expected to require 10kW of power to operate.Traditional power transfer methods for this type of off-site extraction mission would utilize cables, estimated to have a mass of about 7,500kg for five load stations. These transmission lines must traverse large distances, are sensitive to temperature, will be expensive to transport from Earth to the moon, may be a safety hazard for lunar operations, are susceptible to solar flare induced transient effects, have large diameters due to high voltages and power levels, have a large mass, and are difficult to manage due to residual cable stresses.In addition, once the cables are set up, they would be difficult to move in the event that a different facility needs to be powered. Since multi-kilowatt power requirements are envisioned for these work sites, new methods of power transfer must be explored.For comparison purposes, a top-level system design for a traditional transmission line approach was developed. A transmission voltage of 480 V was selected based upon minimum cable sizes