Producing electricity in space from sunlight is used by hundreds of satellites in operation today.

In 1968, Dr. Peter Glaser, formerly of NASA, introduced the concept of a solar power satellite system with square miles of solar collectors in high geosynchronous orbit to collect and convert the sun's energy into a microwave beam to transmit energy to large receiving antennas (rectennas) on earth.

NASA and DoE (Department of Energy) of U.S.A. conducted feasibility study of the proposed SPS in 1970’s.

In 1999 NASA formed SERT, the Space Solar Power Exploratory Research and Technology program to perform design studies and evaluate feasibility.

Solar panels on satellite capture light, sends power to earth using microwave wireless power transmission technology power transmission technology

Signal sent from receiving Signal sent from receiving antenna on earth (green) antenna on earth (green) allows satellite to pinpoint it’s allows satellite to pinpoint it’s microwave beam.microwave beam.

Solar energy conversion Wireless power transmission to the Earth Spacecraft sizing

Two basic methods of converting sunlight to electricity are PV and SD

Photovoltaic cells convert photons into electrical power via a quantum mechanical mechanism.

Solar Dynamic conversion uses a heat engine, consisting of a piston or a turbine which uses expansion of a working fluid to produce motion from heat.

The power could be transmitted as either microwave or laser radiation at a variety of frequencies depending on system design.

the transmitting radiation would have to be non-ionizing to avoid potential disturbances either ecologically or biologically.

To minimize the sizes of the antennas used, the wavelength should be small.

The size of an SPS will be dominated by two factorso the size of the collecting apparatuso the size of the transmitting antenna For best efficiency, the satellite antenna should be circular

and for the probable microwave wavelength, about 1 kms in diameter or larger; the ground antenna should be elliptical, 10km wide, and a length that makes the rectenna appear circular from GSO.

NASA/DOE Reference Model Recent NASA’s concepts

To build this satellite, it was estimated that 500 astronauts must work on this satellite. Mass of

the satellite would be 50,000ton. existence of the rotary joint between the solar array panel and the microwave power transmission antenna.

In 1999 NASA conducted

SERT program. Each solar collector and

power generator are

connected each other by

a tether.

NASA estimates a SSP will need to operate at 1000v or higher, which leads to self-destructive arcing. Current experimentation is at 300 v. Wireless power transmission only recently became a

reality, with small amounts of power over a few feet. Lots of design work left regarding the high temperature

characteristics of the transmitting antenna and the solar array.

Example of self destructive arcing

No pollution after construction Source of energy is free Large amount of energy potential.

Less atmosphere for sunlight to penetrate for more power per unit area

Any location on Earth can receive power Satellite can provide power up to 96% of the time Solar panels do not take up land on Earth Lots of space in space Promote growth of space, solar, and power

transmission technology

solar power satellites are a realistic possibility for solving Earth’s future energy needs in an environmentally clean and safe way.

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