SSP+PowerStar-Initial Design

1

Final Presentation May 5, 2014

Space Based Solar Power

Instructor: Prof. D. C. Hyland

Time: TR, 8:00 9:15am

Location: Rm 204, HRBB

Outline

Introduction: Design Challenge

Motivation for Space Solar Power (SSP)

Previous SSP concepts

Power StarTM overview

System Component Designs 1. Printed power collection and transmission technologies

2. Multi-functional structural materials

3. Micro-wave transmission

4. Orbit/Constellation design

5. Spacecraft utilities design

Ive gone through the Design Review Process with other Professors @ Texas A& M, we all agree it has Great Potential & Technical Feasibility. Shawn P Boike

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Design Challenge

Design a space-based Solar Power System (SSP) One or more satellites that collect solar power

Solar power is converted to microwave radiation

Microwave radiation is beamed to several places on the ground by means of phased arrays

At each reception station the power is converted to DC via a rectifying antenna (rectenna) array

Power is distributed locally, without long-distance transport.

Focus should be on a First Revenue System

We will be assisted by DoD consultants and SSP entrepreneurs

Motivation DoD Petroleum Dependencies

Combat is one of the most energy intensive activities known to man

The military depends on oil to provide agility, global power projection and focused

logistics under hostile conditions and broad climate extremes

Examples of U.S. military operations (Defense Agency Support Center (DESC), FY

Fact Book):

Operation ENDURING FREEDOM, 2.6M gallons (61,500 bbls) per day between Oct 2001 and

Sep 2003

Operation IRAQI FREEDOM, 1.06M gallons (25,300 bbls) per day between Mar 2003 and Sep

2004

Motivation, Continued

Previous SSP Concepts

Reference DoD SSP Overall Configuration

NRL First Revenue System (FRS)

Operational Demonstration of Space Solar Power (SSP): Economic Analysis of a First Revenue Satellite (FRS) by A.C.

Charania, John R. Olds, and Domnic Depasquale

Financial Analysis of NRL SPS Conclusions & Recommendations

Economic analysis of a conceptual FRS based on a 59 MT (in LEO) SSP system delivering 5 MW yields ~$7/kWhr versus the ~1$/kWhr needed to compete in potential niche markets.

Future work for improvement: Refinement of the system both in terms of technical optimization and cost analysis fidelity

One approach would be to constrain the LEO mass and then design the MW-class SSP FRS around that constraint.

Operational Demonstration of Space Solar Power (SSP): Economic Analysis of a First Revenue Satellite (FRS) by A.C.

Charania, John R. Olds, and Domnic Depasquale

So new its scarcely noticed,

So old its almost forgotten

Substrate layer

Trans

mitter

Solar cell Solar cell

Conductive coating (ground)

Power

connectors

Printed Solar Arrays Printed Patch Antennae

Solar-Microwave FabricTM

The New

The Old Echo Satellite Technology

Meridonial Sectors Spherical Balloon

Packaging and Deployment

Negligible final

angular velocity

Rectenna Beacons

Printed microwave

transmitter elements Printed solar array

elements

Random Tessellation to

prevent grating lobes

Substrate layer

Transmitter



In each patch antenna:

Local microprocessor records beacon radiation waveform

Amplifies waveform and emits it back in reverse time.

Power optimally matches desired power distribution on the ground.

No moving parts!

Error Compensation is purely electronic. There is no control/structure Interaction

System Dynamics Sensor measurements

of array element

position errors

Array element

deformation/vibrat

ion

Dynamic feedback

control Actuator

dynamics Actuator commands

Actu

ato

r forc

es

and

torq

ues

Electronic phase

adjustment

Phased Array Gain

Undistorted

radiation pattern

Disturbances

Substrate layer

Transmitter

~ 10cm


~ 1 km


Power

connectors

meridonial sheets with

power coupling

w

Printed microwave

transmitter elements

Printed solar array

elements

Random Tessellation to

prevent grating lobes

Summary Sketch of the Concept Unique features:

Its structure is extremely simple and can be fit into many launch vehicle payload envelopes.

It can gather solar power from any angle and beam power in any direction (s) without slewing or structural deformation.

It has no moving parts.

It can optimally approximate any desired field distribution on the ground.

It requires no in-space assembly or construction

It has no control/structure feedback so the system is guaranteed dynamically stable.

The operation of the phased array is adaptive so that even if severely damaged, the system can retain some level of useful performance.

Outline










20

1. Printed power

collection and

transmission technologies Kim Ellsworth

Clay Matcek

Candace Hernandez

Hyder Hasan

Jose Flores

Robert Wehr

VICOSC PRINTED SOLAR CELL

Victorian Organic Solar Cell Consortium

http://newsroom.melbourne.edu/news/ctrlp-printing-australia%E2%80%99s-largest-solar-cells?_ga=1.64104170.436929901.1396359218

- 1050 watts of power per square meter

- speeds of up to ten meters per minute, or one cell every two seconds

- cells up to 30 cm wide

- printed onto paper-thin flexible plastic or steel

- organic photovoltaic cells

- different types of cells capture light from different parts of the solar spectrum

MIT SOLAR CELLS

Efficiency: 1%, hope to get up to 4%

7 cm x 7 cm generates approximately 50 Volts (~1cm2 gives you 1

Volt)

No change in performance after 1000 flexing cycles

Printed on paper

Still works with 1 micron thick polymer coating submerged in

water

PRINTED PATCH ANTENNAS

Antennas can be inkjet printed onto materials including cotton-

polyester

Flexible substrate allows it to be layered onto desired shape

Multiple layers increase efficiency

More efficient at higher frequencies

15 micrometer printing resolution more than satisfies half-

wavelength requirement

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6693

734

RECOMMENDATIONS: SOLAR CELLS

Set up our own printers for solar cells

Allows us to print on any shape, including beach ball strips

Current research printers are confined to particular sizes, such as size of A3 paper

Allows us to experiment with material on which to print (steel, plastic)

TRL: 4

Not tested in relevant environment

However, mass production is feasible

Estimated cost: $200,000 for printer

10-50 W/m2

Need to look into space viability of organic photovoltaic cells

RECOMMENDATIONS: PATCH

ANTENNAS

Set up a separate inkjet printer for patch antennas

Allows us to print on any shape, including beach ball strips

Allows us to experiment with number of layers for effectiveness and flexibility

Allows us to experiment with printed material (i.e., gold, silver)

TRL: 4

Has not been tested in a relevant environment

Mass production has not yet been attempted

Estimated cost: TBD

Up to 79% efficiency on FR45 resin

Run strip through solar cells printer first, then patch antenna printer.

Outline










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2. Multi-Functional Structural Materials

Mylar BOPET

Kapton Polyimide

Material Comparison

Mylar

Polyester Film made from resin Polyethylene Terephthalate (PET)

Functions at temperature ranging from -70 C to 150 C or -250 C to 200 C when physical requirements arent demanding

Kapton

Organic Polymeric material

Comes in films of types: HN, VN, FN

Does not melt or burn

Functions at temperatures ranging from -269 C to 400 C

Excellent chemical resistance

Mylar

Physical Properties Thermal Properties

Kapton

Physical Properties Thermal Properties

Structural Cross-Section

Mylar

Solar Cell

Copper Grounding Grid

Inward-Facing Antenna/Rectenna

Outward-Facing Antenna/Rectenna

Inward-Facing Antenna/Rectenna

Outward-Facing Antenna/Rectenna

3D Printing Capabilities (Note - More detail in Team 1 slides) Inkjet Solar Cells (left picture)

Printed antenna elements (right picture) have already been successfully integrated with the solid-state devices such as Schottky devices https://www.sbir.gov/sbirsearch/detail/295270

Both are nearly limitlessly flexible

Folding and Storage

Deployment Mechanism

Balloon will be inflated by the sublimation of a powder upon exposure to the heat of sunlight.

This gas will inflate pillows, which will begin the deployment process and prevent the gas from getting trapped in pockets.

Once the pillows inflate, they will vent gas through perforations in the surface of the pillow, inflating the rest of the satellite.

The copper grounding grid will be designed to yield at a certain pressure, providing stability to the satellites shape.

One of the pillows will be designed to rupture the outer surface of the balloon after deployment, allowing the Power Star to release excess gas once the copper grid has just begun to yield.

Echo II Inflation Mechanism

Material Properties

Fiber-matrix composite

Outline










38

STATUS/PROGRESS REPORT

Jeff Campbell, Brandon Saylor, Doug Squires, Hope Russell,

Matthew Koestner, Warren Honc

The Laws of Diffraction & Safe Power Levels

The minimum spot size (rectenna size) on the ground is:

Operational wavelength

transmit distance (35,786 km for GEO)

A

zx

D

z

2

Diameter of the phased array

At each ground station the power density is:

4

Power delivered to an individual rectenna

A

Astation

station

D

DP

z

P

Some fraction of , where:

Total transmitted power from the entire satellite

t

t

P

P

The Laws of Diffraction & Safe Power Levels

max

max

max

If equals the safe power density, , then combining the above equations gives:

4

We assumed 10% of the maximum ground insolation ~

stationPx

21050 The laws of diffraction and the safety requirement imply a rectenna size that is

Therefore the rectenna design decouples from the space segment - We

W m

independent of altitude and wavelength

concentrate

on the space segment.

Microwave Patch Antenna Operation and Dimensions

2L

A patch antenna consists of a metal patch mounted on a grounded, dielectric substrate as shown:

The dielectric provides a resonant cavity to amplify the transmitted signal. Since L is the resonant

dimension, we must have:

Here we shall assume W = L

Optimum Patch Antenna Spacing and Max Power

2 2

2

Total power produced:

12 2 4

Power Star diameter

Average spacing between patch antennas

t A eff s

A

P D Qs s

D

s

2

2

max

Solar cell X antenna efficiency

Solar insolation 1367 W

This is maximum when 2 . Then:

1

4 4

eff

S

t A eff s

Q m

s

P D Q

Max Power vs. Diameter (for various efficiencies)

Over 10 MW

with only 1%

efficiency!

The very same time-reversal principle

has been applied to accoustics. See

Scientific American, November 1999.

Fundamental Power Shaping Concept

The Acoustic Time-Reversal Mirror

Illustration of Power Shaping

The collectennaTM operations are simultaneous. But we illustrate one step at a time.

The next chart shows a simulation of a flat phased array receiving radiation from two beacons on the ground.

Recording the beacon signals, then amplifying them and playing them back in reverse time occur concurrently. To simplify the

explanation, we illustrate these steps separately. First, consider the beacon propagation

On this plane we have two

point sources representing the

beacons

Each pixel on this line

segment is a separate

recorder

When the beacon radiation

reaches the line segment

representing the phased array,

each point on the line records

the wave-form that it sees.

Now turn off the beacon and let each pixel on the line segment re-transmit the wave-form it recorded - but in

reverse time

Note the converging wave

fronts

Each pixel on this line

segment transmits the

recorded signal in reverse

time

The amplitude on the ground

plane has two concentrations

centered on the beacons. If

the transmitting array were

infinite in extent, these would

be point concentrations.

Nor must the phased array be flat!

Beam Shaping Algorithm - Summary

Each patch antenna (actually a transmitter/receiver) senses the beam(s) radiation at its location.

It processes this information and transmits a greatly amplified signal in reverse time.

Control of each patch antenna is purely local. No global, large-scale algorithm is needed.

The patches act independently the resulting transmission pattern is an emergent phenomenon.

Even if the Power Star surface is distorted or damaged, the beam shaping algorithm will perform at some level.

Activities thus far: Solar Array/Patch Antenna size relation research

Patent research for retro-directive arrays

Studied antenna lore based on hemispherical geometries

Explored wireless transmission between interior vehicle hemispheres for subsequent transmission to Earth

Current goals: Formalizing our findings

Calculations and models to be done by this team:

Plotting solar collector area versus satellite radius

Plotting power generation as a function of satellite radius

Calculations for ground spot radius, power density, etc.

Drawings outlining concepts relating to microwave transmission, inter-satellite power transmission, patch antenna function and connections, etc.

Explanation of beam steering and beam splitting capabilities

*These tasks will require little time and effort to complete, as all of the ideas and concepts have been explored

*There is a great deal of knowledge that has been wrapped up in this part of the project. It is difficult to ascertain exactly what we should list and what we should not in our final presentation. If there is anything that should be included that was not listed in the above slides, please let us know!

*Also, completing this teams primary task (modeling the hemispherical array and fault tolerance) proved difficult. Sufficient workable results were not able to be generated, though attempts were made.

What else can we include?

Beacon radiation

Solar radiation

,S B

,S B

,S B

,S B

Interior surface printed with -wave receiver/transmitters (possibly shorter wavelengths)

, exterior surface illuminated by both sun and beacon

External solar arrays power local external transmitters

, exterior surface illuminated by sun but no beacon

External solar array

S B

S B

s power the local internal

receiver/transmitters & they transmit power to the

internal receiver/transmitters in sector ,

, exterior surface exposed to beacon, but not t

S B

S B he sun

Exterior transmitters powered by the local interior

receiver/transmitters (that receive power from , )

, exterior surface shaded from both sun and beacon

Do nothing

S B

S B

Localized Power Distribution

Power Distribution - Summary

Each antenna transmits only if the beacon(s) radiation is received.

Each transmitting antenna draws power from Solar cells in its immediate vicinity (within a few centimeters), or

Through the thickness of the skin from receivers on the inner surface of the skin.

Power distribution to each antenna is local there is no need for a complex power management system.

Strictly local architecture means robustness against partial damage!

Outline










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4. Orbit/Constellation Design

Need a copy of their PowerPoint (Not a PDF)!

Outline










59

TEAM 5 SPACECRAFT UTILITIES DESIGN

TEAM SPOKESMAN: LIGGETT, JUSTIN

ARCE, RAVENNE

DEMPSTER, GRANT

HENLEY, MATT

ROGERS, WILL

TORRES, GABINO

WEEKS, MATHIAS

UPDATE: 4/23/2014 PAGEOS satellite will be researched given similarities and possible improvements when compared to

ECHO.

Attitude Controls/Orbital Maintenance Any attitude/orbital maintenance device that would be used would required a major redesign of the satellite because the options available are thicker than the SSP spacecraft. Research is ongoing.

Deployment Dynamics Pressure vessel with low pressure gas, research is ongoing.

Power Distribution connections were made out of aluminum, research is ongoing. Team One will be contacted. Connections may be changed to copper, Team One will be consulted.

Thermal Controls Approximate temperature of the satellites will be roughly 30C. Rough model of equations for thermal control is being developed. The current assumption is that the material will be Mylar. Research is ongoing.

Launch Vehicle and Deployment craft will be discussed in following slides.

ECHO SATELLITE LAUNCH VEHICLE AND DEPLOYMENT The ECHO satellite was mounted on a third-stage rocket that was part of the Thor-Delta rocket.

The Thor-Delta rocket was in service from 1960 to 1962.

The rocket was composed of a PGM-17 Thor missile (in DM-19 config.), a Delta and an Altair solid rocket motor. Can reach between 1500 and 1700 km in altitude (this was the range for ECHO 1s orbit).

The next slides show examples/depictions of how the ECHO Thor-Delta combination.

A list of rockets is currently being looked over to deploy the SSP Project satellite into orbit.

To left is an example of the ECHOs carrier. The spherical package protected ECHO until it was ready to deploy. At deployment, the two halves popped apart and the satellite inflated.

How the ECHO Satelloon was mounted/deployed. ECHO Satellite 3rd-Stage Mounting

ECHO Satellite is mounted on top of an Altair solid rocket motor. Right image: White canister that spherical contain is on top of.

ECHO

See the similarities between the schematic and the image. It seems that the schematic was used during the Thor-Deltas tenure from 1960-1962.

ECHO Satellite Launch Stages

PGM-17 THOR (IRBM)

Delta (derived from Able)

Altair Solid Rocket Motor

Conclusion

Power StarTM is launched as a small seed, then grows to a mighty sphere.

Although large, it uses the independent action of each small part.

It uses the very new to give new life to an old but beautiful satellite design.

(The Latin means: Nature is greatest in the smallest things)

Natura in Minima Maxima

Documents

SSP+PowerStar-Initial Design