7. The planet is running out of time.
Consider this: every day that you continue to use power generated from coal
fired power stations, you contribute to the eventual collapse of the global
eco-system as we currently know it.
SAVE THE PLANET
PLUG INTO MOST POWERFUL RESOURCE AVAILABLE
THE SUN

11. • a means of collecting solar power in space, for
example via solar cells .
• a means of transmitting power to earth, for
example via microwave or laser .
• a means of receiving power on earth, for
example via a microwave antennas (rectenna).

13. • Photovoltaic (PV) conversion - semiconductor
cells (e.g., silicon or gallium arsenide) to
directly convert photons into electrical power
• Tolerant to the space radiation environment
Solar energy conversion
(solar photons to DC current)

14. From the Satellite
• Microwave transmitter
– Frequency 2.45 GHz
• Power level is well below international
safety standard
• Received at a “rectenna” located on
Earth
• Recent developments – laser

15. Laser power stations, perhaps
drawing energy from the local
environment, might one day
propel spacecraft throughout the
solar system.
Credit:NASA/Pat Rawlings

16. RECTENNA
“An antenna comprising a mesh of dipoles
and diodes for absorbing microwave energy
from a transmitter and converting it into
electric power.”
• Microwaves are received with about 85%
efficiency
• Around 5km across (3.1 miles)
• 95% of the beam will fall on the rectenna

17. • Currently there are two different design types
being looked at
–Wire mesh reflector
• Built on a rigid frame above the ground
• Visually transparent so that it would not
interfere with plant life
–Magic carpet
• Material pegged to the ground
Rectenna Design

18. The rectennas will be huge, but the land underneath need not go
to waste. Since the array absorbs the microwaves, but allows
sunlight and rainfall through, the land could be used for farming
or ranching. Or, as in this case, the rectenna could be built as a
vast set of greenhouses, feeding millions.

19. 5,000 MW Receiving Station (Rectenna). This
station is about a mile and a half long.

20. 20
How large is the GEO solar resource?
1 year x 1 km wide band
≈ 212 TW-years
All Remaining Oil Resource
≈ 250 TW-years
1km

21. •Does not emit greenhouse gases.
•Does not produce hazardous waste
•24 hours a day, 7 days a week, in huge
quantities.
•It works regardless of cloud cover, daylight,
or wind speed.
•Any location on Earth can receive power.
•Lots of space in space.
•Promotes growth of space,solar and power
transmission technology.

26. Harvesting energy from space. This
recent solar power satellite design features
sets of lightweight, inflatable Fresnel
reflectors. These devices focus the Sun's
energy on small arrays of high-efficiency
photovoltaic cells.
Credit: NASA artwork by Pat Rawlings/SAIC
"Sun Tower"

27. • Advantages
–much shorter energy transmission path
lengths allowing smaller antenna sizes,
– lower cost to orbit,
• Disadvantages
–increased debris collision difficulties,
–requirement of many more power stations
to provide continuous power delivery at
any particular point on the Earth's surface.
LEO instead of GEO

28. • power generator - harvesting energy from the Sun
• Two small solar panels could power a communications
satellite
• four panels might power a robotic interplanetary probe,
• six a manned spacecraft
• 20 panels might supply energy to a lunar base.
"Solar Disc

31. • 2001: NASDA (Japan's national space agency) announced plans to perform
additional research and prototyping by launching an experimental
satellite of capacity between 10 kilowatts and 1 megawatt of power.
• 2007: The Pentagon's National Security Space Office (NSSO) issued a
report on October 10th, 2007 that states they intend to collect solar
energy from space for use on Earth to help the United States' ongoing
relationship with the Middle East and the battle for oil. The International
Space Station is most likely to be the first test ground for this new idea,
even though it is in a low-earth orbit.
• 2007: In May 2007 a workshop was held at MIT to review the current
state of the market and technology.
• 2009: A new company, Space Energy, Inc., plans to provide space-based
solar power commercially. They say they have developed a "rock-solid
business platform" and should be able to provide space-based solar
power within a decade.

33. PROBLEMS

34. Environmental
• Possible health hazards
–Effects of exposure to microwaves
• Location
–The size of construction for the rectennas is
massive

35. Economic
• Launch costs are high
International
• Geosynchronous satellites would take up large
sections of space
• Interference with communication satellites
• Low orbit satellites would require agreements
about rectenna locations and flight paths

36. • High Efficiency solar cells and production of
lightweight, solar-cell laden panels
• Wireless power transmission
• Robotics
• Space Transportation
Way To Go…

37. • Ground launch systems such as
– geosynchronous orbit space elevator.
• Launching from the moon
–Cost 100 times lower than from Earth, due
to the lower gravity.
Launch Methods

38. Where SPS will take us?

39. Imagine soaring through space in a vehicle
that could use the Sun to power itself. This
Solar Clipper concept shows how solar panels
could collect the Sun’s energy to keep a
spacecraft moving through our Solar System.

40. The interior of the habitat can be landscaped
with lunar soil and planted. Those living in
space need not be cut off from green growing
things
SPACE SETTLEMENT
home in orbit
Live on the inside of air-tight, kilometer scale,
rotating spacecraft.

41. • More reliable than ground based solar power.
• Promising energy source of the future.
• In order for SPS to become a reality , several
things have to happen:
–Significant breakthrough in technology.
–Building SPS using materials in space.
– International Co-operation.
–Cheaper launch prices.
Conclusion

42. • NASA-www.nss.org
• www.spacefuture.com
References