Post on 14-Apr-2018
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Presentation
Solar Power Satellite
Prepared By : -Akshay Kumar Bajpai
Electronics & Comm. Engg.
Under the guidance of :-
Mr. Arun Kumar Singh
Seminar Coordinator
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What is Solar Space Power (SSP) ?
Solar Energy is captured in space by large photovoltaic
arrays and transmitted via a coherent microwave beamto an Earth receiver where it is converted into either
electric-power or other convenient sources of energy .
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Satellite Orbit Options
Geostationary Altitude: 35,786 km
Inclination: 0
Low Earth Orbits
Critically Inclined Sun Synchronous:
Perigee altitude: 400 km Retrograde inclination: 116.565
Circular:
Altitude: 500 km
Inclination: 45
ETS-VII: Japanese satellite with similar initial conditions Altitude: 550 km
Inclination 35
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Thermal Management
Objective To perform thermal analysis of the satellite and ensure a
suitable operating environment for the payload.
Tools
Thermal Desktop softwareResearch Topics
Low earth orbit environment
Temperature requirements for internal components
Cooling/heating methods
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External Environment
In LEO, the satellite will be heated by: Direct sunlight
Earths albedo
Earths IR emittance
The total heat absorbed by the satellite will not remain
constant. Fluctuations occur due to:
Entering/exiting Earths shadow
Varying surface conditions on Earth
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Satellite InteriorThe interior environment of the satellite must be kept at
a proper temperature range. Most electronic equipment
onboard must operate in a surrounding temperature
range of 0 to 50 degrees Celsius.
Factors to consider for the internal energy balance:
Fluctuating external heat rates
Heat released by electronic equipment
-Low level baseline operation-High level during periodic transmission
Thermophysical properties of structural material
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Cooling/Heating Methods
External
Radiators: Do not require energy. Release heat without re-entry
(thermal diode)
Internal
Thermoelectric Coolers/Heaters: Require energy. Can absorb/emit
heat by reversing polarity
Mechanical cooling: Expander, compressor, or heat exchanger. Takes
up space and weight.
Resistive Heating:Requires energy but elements are compact in size.
Heat Pipes: Passive
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Structural Requirements
The satellite must have ability to: Withstand launch loads
Provide desired rigidity
Protect sensitive payload components fromextreme temperatures.
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Material Selection
Ti6Al4V Titanium alloy VS.
Aluminum Alloy( 7075-T651)
lthough Titanium is 60% heavier
than Aluminum, it is overtwice as strong.
Possibility of having titanium
based honey comb exterior;
joined by a smaller portion ofaluminum interior.
Currently evaluating two different materials:
Materials
PropertiesTitanium
(Ti6Al4V)
Aluminum
Alloy( 7075-
T651)
Units
Density 4.43 2.81 g/cm3
Tensile
Strength880 572 MPa
Thermal
Conductivity6.7 130 W/m.K
Modulus ofElasticity
114 71.7 GPa
Thermal
Expansion8.6 23 *10-6/C
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Honeycomb Layer
Planned use of
Honeycomb design:
Hexagonal Structure
Uses the least amount of
material to create a lattice
of cells within a given
volume
Maintains strength
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Preliminary Sandwich
Structure
Layered design that takes
advantage of each materialsdifferent thermal properties.
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Satellite OrientationOrange-North
Green- South
White- Nadir
Yellow-Zenith
Purple-Leading
Teal- Trailing
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Working
The power generation system (solar cells,
concentrators or other).
The power transmission system, which converts
electrical energy and generates beam via RF
transmission .
The power receiver system, which is closely
linked to RF technology called Rectenna.
Basically Solar Power Satellite Consists of : -
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Continued
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Microwave Power Transmission
Microwave transmission refers to the
technology of transmitting
information or energy by the use of radio
waves whose wavelengths are
conveniently measured of small size i.e.
almost in 10^(-6) meters range, these are
called microwave.
Microwave power transmission (MPT)
uses microwaves to transmit power
through outer space or the atmospherewithout the need for wires, so called
wireless transmission .
NASA Proposed Model
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Rectenna
A rectenna is a rectifying antenna that is used to
directly convert microwave energy into DCelectricity. Its elements are usually arranged in a
multi short-dipole element phased array to make it
directional.
PROTOTYPE OF ARRAY OF
DIPOLE ANTENNA
RECTENNA
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5,000 MW Receiving Station
(Rectenna)
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Why This ???Following wood, coal, and oil, the 4th energy must be*:
Non-depletable - to prevent resource conflictsEnvironmentally cleanto permit a sustainable future
Continuously Availableto provide security regarding availability
In a usable formto permit efficient consumption & minimal
infrastructure
Low cost - to permit constructive opportunity for all populations
A portfolio of substantial investmentsare needed, but
options in the next 20-30 years are limited
Ad E h b d S l
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Advantages over Earth based Solar
Power
There is no air in space, so the collecting surfaces could receive much
more intense sunlight , unobstructed by weather.
Relatively quick redirecting of power directly to areas that need it
most. Longer collection period: Orbiting satellites can be exposed to a
consistently high degree of solar radiation , generally for 24 hours per
day, whereas surface panels can collect for 12 hours per day at most.
Elimination of weather concerns, since the collecting satellite wouldreside outside of any atmospheric-gasses, cloud cover, wind, and other
weather events.
Elimination of plant and wildlife interference.
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Drawbacks
Costprototype costs $74 billion .
Microwave transmission : -
a) Interference with other electronic
devices .
b) Health and environmental effects . Complexity30 years to complete .
Size6.5 miles long by 3.3 miles wide , and
due to this reason space debris are major hazardto the project .
Maintenance & Construction of satellite is
other important challenge .
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Solutions
One time installation charges .
SPACE-BASED POWER STATION can be used for
its maintenance .
Like Atomic Power Plant , SPS station can be situated
away from cities .
As far as size is concerned, research is going on , for
using LASER TECHNOLOGY instead of
MICROWAVE , which will no doubt decreases the size
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Future Applications
The SPS system appears as a promisingsolution for power delivery to elements on
planet surfaces .
It would also be helpful as a power source to
many of our satellite .
It can be beneficial for several projectscarried on moon or other parts in the near
universe .
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Conclusion
More reliable than ground based solar
power
In order for SPS to become a reality
several things have to happen:
a) Government supportb) Cheaper launch prices
c) Involvement of the private sector
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THANK YOU