Solar power satellites have been proposed as a way to collect solar energy in space and transmit it to receivers on Earth. In 1968, Dr. Peter Glaser introduced the concept of using large solar panels in geosynchronous orbit to convert sunlight to microwaves and beam the energy back to rectennas on Earth. NASA and the Department of Energy studied the feasibility in the 1970s. In 1999, NASA initiated the Space Solar Power Exploratory Research and Technology program to further design studies. While solar power satellites could provide a continuous source of clean energy without pollution, many technical challenges remain regarding construction, power transmission levels, and thermal management that require more research and development.

3.  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.

5.  Solar panels on satellite
capture light, sends power to
earth using microwave wireless
power transmission technologypower transmission technology
Signal sent from receivingSignal sent from receiving
antenna on earth (green)antenna on earth (green)
allows satellite to pinpoint it’sallows satellite to pinpoint it’s
microwave beam.microwave beam.

6.  Solar energy conversion
 Wireless power transmission to the Earth
 Spacecraft sizing

7.  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.

8.  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.

9.  The size of an SPS will be dominated by two factors
o the size of the collecting apparatus
o 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.

10.  NASA/DOE Reference Model
 Recent NASA’s concepts

11.  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.

12.  In 1999 NASA conducted
SERT program.
 Each solar collector and
power generator are
connected each other by
a tether.

13.  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

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

15.  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

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

17. ANY QUEARIES ?