Table Top Solar Power Beaming Demonstrator Project

Demo Concept


Advanced societies worldwide have evolved economies that are heavily dependent on low cost energy. Our present level of technology mostly utilizes energy derived from hydrocarbon resources (oil, natural gas, and coal deposits) created by natural processes that occurred over eons of time and we are consuming those resources at a rate millions of times faster than they are being replaced. As more of the world makes the transition to an advanced energy-dependent economy, the demand for energy will inevitably increase and it is obvious that we will eventually exhaust these resources. In addition, production of energy from these resources (mostly by combustion) releases vast amounts of pollutants into the atmosphere with results that are not fully understood. This leads to the possibility of global warming with catastrophic effects on our environment. Finally, the United States (and most of the other technologically advanced countries) consume more energy than they are able to produce from their own hydrocarbon resources and must import hydrocarbons from areas of the world that are politically unstable. This places the advanced economies in a vulnerable position where our economies and lifestyles depend on circumstances beyond our control and cause our motives to be suspect in much of the world.

All of the above circumstances make it increasing imperative that we develop alternate ways of meeting our energy needs using renewable non-polluting sources. Many methods are under investigation including Earth-based solar, wind, hydroelectric, wave motion, ethanol, methanol from waste recycling, geothermal and fusion power, but each of these has significant limitations and/or problems. A method that has been studied since the 1960's is harvesting energy from sunlight in geostationary orbit and transmission of that energy by microwave beaming to receiving stations on the Earth's surface. A major study of this concept was conducted by the Department of Energy, NASA, Boeing, Rockwell International and others in the 1977 - 1981 time frame. An executive summary of this work is available on the National Space Society website at:

and a detailed description of the proposed Reference System is available at:

This study proposed a 20 year research and development phase followed by a 30 year deployment phase in which two satellites and ground receiving stations were built per year, each generating 5 gigawatts of electrical power. At completion this would create a total of 60 satellites generating a total of 300 gigawatts of electrical power. (Roughly the equivalent of 170 conventional coal-fired power plants.) The expected cost of electrical power from this system was about 5 cents per kilowatt-hour. (A competitive rate in today's market.) Had this work proceeded as the study proposed, we would now be 8 years into the deployment phase and generating the electrical power equivalent of about 45 coal-fired power plants.

Additional references on this study and other information on solar power beaming may be accessed at:

The overall conclusions of these early studies were that the concept is technically feasible but there remain significant questions of environmental impact and worker safety, and the economics were not very favorable under the circumstances existing at that time.

Other studies include work by William C. Brown at Raytheon in 1987 on an improved rectenna design available online at:

As a result of the ongoing concerns over security of our energy supply, the National Security Space Office (NSSO) launched a new effort in 2007 to revisit the concept of spaced-based solar power (SBSP). A summary and links to relevant documents may be found at:

In response to this initiative, thirteen organizations including the Moon Society interested in promoting SBSP formed an alliance called the Space Solar Alliance for Future Energy (SSFAE) (see Moon Society announcement). In order to promote public awareness and support of the initiative, the Moon Society has begun a project to fabricate a number of table-top demonstration systems suitable for public display where opportunities arise.

Project Goals

The primary goal of this project is to design and fabricate a small number of table-top systems demonstrating end-to-end power beaming that may be used for public display and education. Desirable attributes of this system include:
  • The system must be small enough to disassamble and pack into no more than two carrying cases transportable as airline baggage.
  • Within the above constraint, the system shall be as close as possible to the real technology that would be used in power beaming.
  • The system shall show what a power beaming system looks like.
  • The system shall show that the technology works and how.
  • The system must meet all United States rules for maximum permitted exposure to RF fields.
  • The transmission path shall permit a member of the public to hold their hand in the beam with no harmful effect.
  • The system shall transmit and recover enough energy to power one or more LED's at an intensity readily seen.
  • The electronics shall utilize commercial off-the-shelf (COTS) technology to the greatest extent possible to minimize cost.
  • The system must meet all legal requirements for operation as a demonstration system within the United States.
The graphic at the top of this page illustrates an initial concept for the system. Key features of this concept are:
  • The two large panels deployed to either side of center illustrate gathering of power with solar panels but are for illustration only and are not functional components.
  • Power is beamed from a transmitting antenna located about 1 foot above the table in a downward direction.
  • Power is received by a rectenna (antenna plus rectifier) resting at the base of the system.
  • Power recovered from the rectenna produces a visual indication of received power.
  • The path between the transmitting and receiving antennas is accessible so that a person may place his hand in the path and an obstruction may be placed in the path to show interruption of power transmission.
  • The remainder of the table top space may be utilized to show a representation of a city or other terrain at the Earth's surface.
An alternate concept might separate the transmitting portion from the receiving portion of the system and reorient the antennas to beam power horizontally. This would have the advantage that the two halves could be spaced further apart as space permits to show transmission over greater distance. It will be necessary to conduct measurements of the coupling between the antennas to determine if this is feasible.

Project Definition

This project will be conducted in three phases:

Phase 1

In Phase 1, a design for the table top demo system will be developed and cost estimates prepared for the remaining Phases. Specific tasks to be accomplished include:
  • Prepare electronics block diagram.
  • Determine sources and pricing for off-the-shelf electronic components.
  • Identify components that are not available off-the-shelf.
  • Create designs for components that must be custom made and conduct simulations of proposed designs to verify expected performance.
  • Obtain quotes to fabricate custom-made components.
  • Perform calculations and simulations and conduct measurements on selected components to predict overall system performance.
  • Design the stand(s) and display components.
  • Obtain cost estimates and or quotes to construct stand(s) and display components.
  • Prepare cost estimates and budgets to complete Phases 2 and 3.

Phase 2

In Phase 2, one complete working prototype of the system will be constructed and performance will be measured to verify that project goals are met. On completion of Phase 2, the prototype will be available for use as a demonstrator. It is likely that a small quantity of the custom made parts will be obtained at the same time as the prototype parts to gain more favorable pricing.

Phase 3

Phase 3 will construct a number of copies of the system for distribution to interested parties. This quantity has not yet been determined.
Check the Project Status page for current status.


Copyright © 2000-2009 The Moon Society. All Rights Reserved.
Questions and comments to:

Submit a Request to update this page