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. Summary
NASA 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 and voltage ranges available directly from series/parallel combined solar cells. Higher voltages
are possible but conversion losses, insulation requirements, and other inefficiencies become
driving factors. For five 10 kW load stations located 2 km away from two generation stations, the
following power transmission page link system parameters are calculated and compared to
corresponding parameters for a traditional transmission line approach

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