ssp by akshay

7/30/2019 Ssp by Akshay

1/24

Presentation

Solar Power Satellite

Prepared By : -Akshay Kumar Bajpai

Electronics & Comm. Engg.

Under the guidance of :-

Mr. Arun Kumar Singh

Seminar Coordinator


2/24

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 .


3/24

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


4/24

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


5/24

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


6/24

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


7/24

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


8/24

Structural Requirements

The satellite must have ability to: Withstand launch loads

Provide desired rigidity

Protect sensitive payload components fromextreme temperatures.


9/24

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


10/24

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


11/24

Preliminary Sandwich

Structure

Layered design that takes

advantage of each materialsdifferent thermal properties.


12/24

Satellite OrientationOrange-North

Green- South

White- Nadir

Yellow-Zenith

Purple-Leading

Teal- Trailing


13/24

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 : -


14/24

Continued


15/24

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


16/24

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


17/24

5,000 MW Receiving Station

(Rectenna)


18/24

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


19/24

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.


20/24

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 .


21/24

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


22/24

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 .


23/24

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


24/24

THANK YOU

ssp by akshay

Documents