Table Top Solar Power Beaming Demonstrator Project

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Background

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:

http://www.nss.org/settlement/ssp/library/DOESPS-StatementOfFindings.pdf

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

http://www.nss.org/settlement/ssp/library/1978DOESPS-ReferenceSystemReport.pdf

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:

http://www.nss.org/settlement/ssp/library/doe.htm

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:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870010123_1987010123.pdf

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:

http://www.nss.org/settlement/ssp/library/nsso.htm

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 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 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.

Project Definition

Phase 1

• 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

Phase 3