space based solar power
DESCRIPTION
Presentation by Dr. Neville Marzwell. A great summary of the status of the technology.TRANSCRIPT
The Technical Challenges for Space Solar Power
Neville I. Marzwell, Ph.D. Advanced Concepts - Technology Innovations
NASA- Jet Propulsion [email protected]
September 2007
Overview of Forces affecting Space Solar Power Challenges and Opportunities
• Global climate change caused by accumulating concentrations of greenhouse gases in the atmosphere is a growing concern– Continuing improvements in efficiency are being more-than-offset by
rapidly growing global demand for new power plants• Stabilizing the carbon dioxide-induced component of climate change is
an energy problem• By 2050-2100, ~ 15TW to 40TW of Carbon-neutral energy must be
available if CO2 levels are to be stabilized at 2- to 4- times pre-industrial levels
• Only a handful of base load power options exist that can make a meaningful contribution to that level of generation capacity– Space Solar Power (SSP) is one of those options
• A constellation of large Space Solar Power Satellites (SSPS) deployed in a family of geosynchronous Earth orbits has the potential to deliver 10s to 100s of Terawatts to markets worldwide
• The policy environment and programs related to SSPS have varied widely during the past 40 years--and continue to be very uncertain
3
The Energy Challenge: Trends of Concern
Asia56%
Africa13%
Middle East3%
Western Europe 5%Eastern Europe
7%Our Hemisphere
13%(US = 4%)
• By 2025, the world will have added 2 billion more people, 56% of the global population will be in Asia, and 66% will live in urban areas along the coasts
• Increased CO2 production may alter the Earth’s climate, possibly causing:
– Rising ocean levels and loss of coastal areas– More intense tropical storms & humanitarian ops– Agricultural climate change—causing migration,
and shifts in power, ethnic & land based conflict
Climate Change
Population
American Competitiveness
• The U.S. is losing global market share & leadership
• R&D investments & skilled workforce are declining
– "a major workforce crisis in the aerospace industry…a threat to national security and the U.S. ability to continue as a world leader.”
Energy
• Energy growth tracks w/ population & economic growth
• Liquid fossil fuels may peak before alternatives come on line causing inability for supply to match demand, shortages & economic shock, instability / state failure, and great power competition
• Three energy concerns: 1) mobility fuels, 2) base-load electricity, 3) peak-use electricity
4
Breakdown of Energy Use - 2005 Estimated values primarily from EIA projections
• ENERGY USE GLOBAL US• Electricity ~ 2,400 gw ~ 460 gw• Generating Loss ~ 2,600 gw ~ 840 gw• Fuel use: ~ 9,500 gw ~ 2,100 gw• Total ~ 14,500 gw ~ 3,400 gw -
World needs to replace ~ 10,000 Gigawatts– ~ 85% of US use comes from fossil fuels.
– US needs to replace ONLY about 2300 Gigawatts.
5
The Energy Challenge Future Energy Options Must Be…
• Following wood, coal, and oil, the 4th energy must be*:
– Non-depletable - to prevent resource conflicts
– Environmentally clean – to permit a sustainable future
– [Continuously] Available – to provide base-load security for everyone
– In a usable form – to permit efficient consumption & minimal infrastructure
– Low cost - to permit constructive opportunity for all populations
• A portfolio of substantial investments are needed, but options in the next 20-30 years are limited…
* Adapted from Dr. Ralph Nansen’s book, “Sun Power”
SourceSource CleanClean SafeSafe ReliableReliable Base-loadBase-load
Fossil FuelFossil Fuel NoNo YesYes Decades remainingDecades remaining YesYes
NuclearNuclear NoNo YesYes Fuel LimitedFuel Limited YesYes
Wind PowerWind Power YesYes YesYes IntermittentIntermittent NoNo
Ground SolarGround Solar YesYes YesYes IntermittentIntermittent NoNo
HydroHydro YesYes YesYes Drought; Complex SchedulingDrought; Complex Scheduling
Bio-fuelsBio-fuels YesYes YesYes Limited Qty – Competes w/FoodLimited Qty – Competes w/Food
Space SolarSpace Solar YesYes YesYes YesYes YesYes
6
GLOBAL CARBON FUEL REPLACEMENT- 2005 ADEstimated values primarily from EIA projections
69% OR 10,000 GW MUST BE REPLACED~ 31% OR 4500 GW
DOES NOT NEED TO BE REPLACED
10000 GW - 69%Carbon Fuel Use
MUST BEREPLACED
8600 GW - 60 %Carbon Fuels
1900 GW - 14%Renewable
Fuel, ElectricalNOT REPLACED
900 GW - 7%Renewable
Fuels
9,500 GW - 66%Non-Electrical
- Fuels -
1000 GW - 7%RenewableElectrical
1400 GW - 9%Electrical USECarbon based
Generation
2600 GW - 17%Generating
LossesNOT REPLACED
4000 GW - 27%Electrical
Carbon-based
5,000 GW - 34%Electrical Use
And Generation
14,500 GW - 100 %All Global Energy Use
Fuels & Electrical Generation
7
Export MarketsExport Markets
SBSPSBSP
Stable PopulationStable Population
DoD, National, and International Impact Invest, Survive, Flourish and Grow – A Future History
Wireless Power Wireless Power TransmissionTransmission
OMVOMV
IndustrializationIndustrialization
TourismTourism
Stellar ProbeStellar Probe
Hurricane Hurricane DiversionDiversion
AsteroidAsteroidDefenseDefense
Space RadarSpace RadarTraffic ControlTraffic Control
““Dredge Harbor”Dredge Harbor”
BeamedBeamedPropulsionPropulsion
Sustainable CivilizationSustainable Civilization
Nations developNations developLess PovertyLess Poverty
DemographicDemographicTransitionTransitionReduce GHGReduce GHG
Reduce ConflictReduce Conflict
Stable ClimateStable Climate
TetherTether
TelecomTelecom
TravelTravel
Reusable Reusable Launch VehicleLaunch Vehicle
Directed EnergyDirected Energy
ISRUISRU
EnergyEnergy InfrastructureInfrastructure
Clean EnergyClean Energy
Growth in GDPGrowth in GDP
8
Capabilities and Challenges If this has been looked at before, what’s changed?
9
The 1 GW system would be BIG • The collector would cover an area equal to
that of a city like Austin or 350 square km.
• It would weigh over 3.5 Million Tons.
• It could cost over $37 Billion dollars.
• It would also need a massive pump-generating storage facility and 2 reservoirs, which would cost about $12 Billion.
• This system as described has no reserve storage to cover totally cloudy days.
10
Components of an SPS in Orbit:• The Solar Collector array in Space consists of
photovoltaic film on a plane several miles across. • Power from the collectors goes via conducting cables
to the phased array Transmitting Antenna.• The Transmitting Antenna is a disk about 1 km
across, attached to the collector array. It sends power to the ground 23,000 miles below.
• The Rectenna (Receiving antenna) is an array of fixed wire dipole antennas covering an oval area on the ground several miles across. It very efficiently captures the microwave energy. This is then converted into usable grid electricity.
SSP - Technology Subsystem Elements
1.2 GW Power to Local
Distribution
Overall Dimensions:
~5 km x ~15 km
6.5 km x 8.5 km RectifyingAntenna
(Rectenna at 5.8 GHz)
High Power Density
Microwave Beam
Structural Elements
Solid State WPT
Multi-Bandgap PV
Optical Elements
RF Elements
Power System Elements
Logistical
Materials
Low Power Density
Microwave Beam
Placed in Earth Geo-stationary Orbit
Typical Scenario
Large SPS in GEO(e.g., 24 Satellites & ~30 GW Total)
Microwave Power Transmission(2.45 GHz or 5.8 GHz)
Power ~ 1.2 GW (Delivered on the Ground at Remote Locations)
12
Launch Challenge: Costs Will Benefit From Economies of Scale
Courtesy of Mr. Gordon Woodcock
Disregard this curve, it was added by someone else
Expendable Launch Vehicles
Fully Reusable Launch Vehicles
13
Solar Power Satellite can be Modular
Technology has improved, even more since 1989,oil is now over $75 per barrel and rising
Size and Structural Challenge:Technology is maturing fast for possible size reduction
.
1 2 3 4 5 6 7 8
TECHNOLOGY READINESS LEVELS
PROOFED CONCEPT
EXPERIMENT
ORBITAL DEMO
ORBITAL FUNCTIONAL PERFORMANCE
CONCEPT CHARACTERIZATION
CONCEPT EVALUATION
TECHNOLOGY FEASIBILITY
STUDY
MECHANICAL DESIGN
DEMONSTRATION
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Ground Demos Flight Demos
SSP System Study Results
• Potential Structural Characterization
•Packaging Efficiency
•Element Deployment Control
•Rigidized Elements
• Controlled/Rigidized Structure
• Launch Restraint/Release
• Ascent Venting Struct. Elements
• Multiple Element Performance
• Geometric Precision
• Thermal Stability
SSP INFLATABLE SPACE STRUCTURESTECHNOLOGY DEVELOPMENT
Scale Hardware
Functional Components
Breadboard/Structural Elements
Very Large Scale High Performance Structure
• Initial Geometry/Precision
• Deployed Stiffness
• Thermal stability
• Launch Release
• Analytical Model(s) Validation
Moderate Size System
SMALL SATELLITE MISSIONS
SMALL REFLECTOR MISSIONS
MODERATE SCIENCE MISSIONS
SUNSHIELD & SOLAR SAIL MISSIONS
• Venting Technique Validation
• Controlled Deployment
• Launch Release
• Deployed Stiffness
• Initial Geometry
Small Prototype Functional System
Large deployable structures
Sub-scale SSP demo
16
Base and Peak Loads…Need Power Storage
Typical Base and Peak Loads for a Large City
0200400600800
10001200140016001800
1:00 3:00 5:00 7:00 9:0011:0013:0015:0017:0019:0021:0023:00
Time of Day - 24 hour clock
Megawatts of Load
PeakBase
17
18
Orbits: SPS in Geosynchronous orbit.
~1980 Reference System
19
Space is the Place for Solar Power
• In Geosynchronous orbit, the Satellite stays over one spot on the equator all the time.
• It faces the sun all the time, generating power 24 hours a day, 7 days a week.
• It only rarely hits the Earth’s shadow.
• The Rectenna does not need to track it.
• Sunlight is 30% stronger in orbit.
• The satellite has virtually no moving parts.
20
GEO, LEO vs. MEO (Part 1)• GEO: Proposed 1980
- Higher launch cost versus MEO/LEO
- Very large path distance requiring antenna/rectenna sizes which far exceed the state of the art frequencies (2.35 GHz, 5.8 GHz)
• LEO Benefits: Proposed IAF 2006- Lower launch cost (7 times cheaper per Kg)
- Shorter beam path distance (500 km vs. 35,680 km)- Antenna sizes 70 times smaller
• LEO Challenges- Orbit used by communication satellites
- Adaptive beam steering, requiring a sophisticated phase array antenna to track rectenna on the Earth with very large relative motion velocity, while simultaneously tracking the sun- Lack of solar illumination (50% darkness), difficulty rejecting heat- Only a small area of the Earth can be covered which necessitates large number of satellites (12) compared to (3) for GSO
• MEO offers the benefits of GEO at lower cost- Altitude of 11,000 - 12,000 km : radiation level low, costs are modest, orbital period of about 6 hrs, so sun synchronous orbit can be achieved with 4 orbits per synodic day- Minimum constellation of 4 satellites in 2 orbital planes. Each orbital plane is orthogonal to the ecliptic, and orthogonal to the orbit plane. Each satellite orbit is inclined at 66.7 degrees to the equator. The ecliptic is the Earth’s orbit around the sun which is at an angle of 23.3 degrees to the Earth’s equator
21
GEO, LEO vs. MEO (Part 2)• Advantages of the Proposed Approach
1) approximately 30% of the Earth's surface is visible to each satellite. Each satellite is in sunlight approximately 90% of the time (most of the year continuous sunlight, for a few weeks in eclipse season satellite is in darkness about 20% of each orbit)
2) Beam path length is about 30% versus GEO, affording corresponding smaller antenna and rectenna. Each satellite in each orbital plane is at 180 degrees to the other satellite in the same orbital plane.
3) Each satellite pair (in one plane) is at 90 degrees phase to the other pair (in the other plane), meaning that a neo-tetrahedral configuration is maintained, thus every point on the entire world is in the field of view of at least one satellite for about 90% of the time.
4) The special distinction versus LEO is that no beam steering is required, so in this respect the satellite design is very similar to a GEO spacecraft. Because the Sun/Earth angle is always 90 degrees, a constant fixed axis rotating antenna despun platform can be employed. The solar array tracks the Sun, and a despun platform tracks the Earth, rotating once every six hours. No dynamic beam steering is required, unless there is a need to serve a different rectenna on the Earth
5) For a nearly half the time, the MEO constellation would be able to provide better service than GEO satellite to rectennas in high latitudes; e.g. north of 34 degrees north (and south of 34 degrees south). This is because for approaching half of each orbit the MEO satellite would be at a higher elevation above the horizon than an equatorial GEO satellite.
22
Advantages of the Rectenna instead of a ground solar collector:
• It is an array of thousands of small wires.• The rectenna also has no moving parts. • Wind, hail, and dust can not damage it.• It is much smaller and uses much less materials
than a ground solar collector.• It collects energy all the time, 4 times more
efficiently than a ground solar collector.• Backup satellites can be switched in very rapidly.
23
Rectenna from above
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CHALLENGE: SSP Wireless Power Transmission TechnologyAccomplishments:
1. Developed WPT Link Budgets for three 5.8 GHz Systems using Klystrons, Solid State Devices and Locked Magnetrons.
2. Formed NASA WPT Working Group with weekly telecons involving up to 6-NASA Centers, 4-Univ., 4-Industry members,covering Microwave, Laser and Redirected Sunlight WPT systems. Most emphasis on microwaves, but some Lasers.
3. Began NRAs on circularly polarized rectennas, Texas A&M, GaN Class-E amplifier, Rockwell Science Center, Light weightphased array module study, Boeing Phantom Works and a table-top retrodirective phased array demo for public demo, JPL.Demo phased array at JPL terminated due to X3-cost growth. Low-cost phased arrays is an oxymoron.
4. Developed white-paper on SSP spectrum allocation issues as follow on to SSP Question submited to ITU from Study Group 1A.
5. Performing detailed investigation into high-power microwave waveguide and filters multipacting breakdown margins.(Multipacting=RF synchronous, reinforced multiple electon impacts into parallel electrodes in a hard vacuum yielding secondary emission cascade resulting in an RF short circuit. Fixes are to modify secondary multiplication surface, fill or pressurize guides)
6. Investigating systems for power beam safety and wrote a paper on Space Policy Issues of SSP WPT beams.
7. Provided estimates of areal mass density, specific power, system element efficiencies, voltages, operating temperatures, etc.to the SSP System Study Group. Inputted pointing errors, required surface errors, subarray sizes, etc. to the Structures Group.Operating voltages, currents and regulation required to the PMAD Group. Land area required and biota interactions to theEnvironmental Group. Assembly, maintenance and phase calibration interface data supplied to the Robotics Group.
8. Identified key problems in the RF-Spectrum-EMC, thermal, and grating-lobe control areas, in addition to RF-breakdown.
State of the art (SOA), but applicable quantitative numbers and examples ( mostly Raytheon, ground-based) are given below with corresponding SSP in-space requirements for comparison of the required technology challenges .
25
5.8 GHz GEO WIRELESS POWER TRANSMISSION SYSTEM DESIGN EXAMPLE
DC Power Distribution
DC-RF Power Conversion Efficiency
Waste Heat Removal
Source PMAD
Subarray Aperture Efficiency
Subarray Failures
Amplitude Errors &Taper Quantization
Phase Errors
Electronic Beam Steering Scan Loss
Transmitter Monitor & Control System
BEAM SAFETY SUBSYSTEM
Beam Coupling Efficiency
Propagation Impairments
Polarization Mismatch
Rectenna Aperture Scan Loss
Rectenna Aperture Efficiency
Rectenna RF-DC PowerConversion Efficiency
Waste Heat Removal
DC Power Collection
Load PMAD
Rectenna Monitor & Control System
Dt = 500mDr = 7500 mmkmb = 0.9182Edge Taper = -10.02 dBPeak/Ave P.D. = 2.35
Clear Air = -0.05 dB = 0.9885
4mm/hr Rain @ 0.01 dB/km X 2.5 km = -0.025 dB = 0.994
0.90 -0.458 dB
0.95 -0.706 dB
0.96 2% Random Failures
0.986 10-Step & +/- 1 dB
0. 97 10 deg rms
0..977 -0.1 dB max
0.933
0.918
0.999 +/- 2 deg
0.999 -0.0 dB max
0.95
0.86
EMC & Diplexing Filters
0.794 -1 dB
EMC Filtering
0.891 -0.5 dB
Rectenna Element Failures
0.99 -1%
0.395 Overall WPT Efficiency
RADIATE
RECEIVE
PROPAGATE
WPT SYSTEM PARAMETERS
26
5.8 GHz Magnetron Directional Amplifier (MDA) SSP Subarrays*
Richard M. Dickinson, JPL
4m X 4m Edge Subarray3 X 3 = 9-MDAsYielding ~ 2.8 kW/m2 PFDand thus -9.5 dB Aperture Taper
5 kW RF out, 85.5% efficient Magnetron, ~1kg,6 kV, 1A & 70 W, 5s-Starting Filament & Off
44 cm dia., 350 deg C PyrolyticGraphite Radiator Dumping 850W
Waveguide Phase-Reference, Circulator, Filters, ASIC- MMIC, Buck-Boost Coil, Guide-Tuner and Power Distribution
Portion of 4m X 4mCentral Subarray with 9 X 9 = 81-MDAsYielding ~ 25 kW/m2 PFDfor 1.2 GWe System
Slotted WaveguideTransmitting Antenna~ 6 kg/m2, 0.5 mm (.02’)Aluminum (~ 1100slots/m2)~ 3.2 cm thick (Cross Feeds + Radiating Waveguides)
* Var. of Brown, W. C.,”Satellite Power System (SPS) Magnetron Tube Assessment Study, “ NASA Contract NAS-8-33157, for MSFC, 7/10/80.
Two Central Devices Diplexedfor Retrodirective Pilot BeamReceiver Function
MLI BlanketsOver 95 deg C Electronics
Peak Mass Density = Transmitter@ 5.7 kg/m2
Antenna @ 6 kg/m2
Absorptive & Reflective Filters @ 2 kg/m2
HVDC Distribution [email protected] kg/m2
TOTAL RF Peak Density = 14 kg/m2
Edge Subarray Density = 7.7 kg/m2
Total “Average” Mass Density ~ 32 kg/m2
NOTE:Not To Scale
Est. [email protected]/kW ~20kg/m2
27
SSP Wireless Power Transmission Technology-I
1. SOA DC-RF Conversion -%/W/GHz/C .76/6.9/8.0/125 .83/900/2.45/135 .75/50kW/2.45/100
SSP Required= .90/6-60/5.8/300 .855/6kW/5.8/350 .83/26kW/5.8/500
2. SOA Large Phased Arrays (non Retrodirective) PAVE PAWS@UHF Cobra Dane@L-BandTHAAD ~2mX5m, 25,344 X-Band Elements 31m dia(twin)-3/4MW 29m dia-1MW(TWTs)TRW- Capistrano HPM 48-6ft S-Band Dishes 1,792 active elements of 5354 15,3600 elements
SSP @5.8GHz, 500m dia, ~2 GW CW out, #elements= 83,841,253 381,618 82,589
3. 2.45 EMC dBc/Hz@50MHz & 2ndHarmonic= -150 & -40dBc -190 & -60dBc -160 & -30dBc
SSP EMC Requirement @ 5.8 GHz+/- 75 MHz & Fleet of ~ 100 SSP in View= -174dBW/m2/Hz?
4. SOA Spacecraft Filter Multipacting Breakdown Margin= 6-10dB at C & Ku-Band 10-50W, 13 yrs.
SSP @ 5.8GHz Margin Requirement >6 dB for 40 years= 60W 6 kW 26kW
Solid State Magnetron Klystron Phase Injection Locked
Richard M. Dickinson, JPL
28
SSP Wireless Power Transmission Technology-II
5. SOA CW Microwave Power $/W, GHz, Quan.= $3, 1.9,100s $.025,2.45,100Ks $1.25,UHF,2s
SSP Required CW Microwave Power at 5.8 GHz, Fleet of 100 Quantity = $1-2/W, 105-109
6. SOA Microwave Device, Thermal & PMAD kW/kg= .01 .2 .02
SSP WPT Array System Specific Power (kW/kg) .42 .34 .3
Key Technology Item s GaN@300C PLL-ASIC 5-Stage MDC@500C
Solid State Magnetron Klystron Phase Injection Locked
The near term technology to be developed is the ASIC/MMIC for using modifiedcooker tube magnetrons as phased array sources for retrodirective power transmittingphased arrays in beaming power to station keep geostationary stratospheric platforms for telecommunication and scientific observation applications. ( ~ $ 1-2M/ 1 yr)
50-100V 3.5-6kV 28kV
ASIC=Applicaion Specific Integrated Circuit GaN=Gallium Nitride MDC=Multiple Depressed Collector PLL=Phase Locked Loop PMAD=Power Management & Distribution dBc=Decibels Below the Carrier Level dBW=Decibels Relative to a Watt
Richard M. Dickinson, JPL
29
SSP Wireless Power Transmission Technology-III
To Lower the Barriers to SSP, Technology is Needed to Permit:1. Electromagnetic Compatibility (EMC)-A. Power Beam Frequency Allocation at wavelengths with less than 5% (0.2 dB) atmosphere propagation impairment for 99.5% of a year. Bandwidth at auctionfor less than $100/Hz? WPT Service definition in the International TelecommunicatonUnion (ITU) by over 50% of the 182 member countries.
B. Close-In Carrier Noise and Harmonic Filtering in GEO, with less than 10% (0.5 dB) insertion loss and greater than a safety factor of 2 (Voltage ratio, 6 dB Power) multipacting breakdown margin for less than 2 kg/m2 areal density.Less than 15% (0.7 dB) insertion loss for ground based rectennas at less than $0.2/W.
2. Lifetime- 40 year lifetime for high power microwave devices and parts in GEO.
3. Beam Safety Perception- The “fear of frying” must be overcome by working demosand public education of beam safety marking and intrusion detection with safe beaminterruption and restoration, for less than $.005/kWh delivered energy.
Richard M. Dickinson, JPL
30
Bill Brown’s* Magnetron Directional AmplifierUsing A Modified Cooker Tube
AmplitudeComparator- Driver
Buck-Boost Coil
Modified Cooker Magnetron
Waveguide Reactance Tuner
FerriteCirculator
Directional Couplers
To Antenna
Phase Comparator
RF Driver Amplifier
5- Bit PhaseShifter
Phaser DriverPhaser Commands
Power Output Ref.
2.45 GHz Ref. Signal
React- anceDriver
WCB MDA MMIC-ASIC (TBD)
Power Converter
Supply Voltage
* Brown, William C.,”Development of Electronically Steerable Phased Array Module (ESPAM) with Magnetron Directional Amplifier (MDA) Power Source,”Final Report, Microwave Power Transmission Systems, Weston MA, Texas A&M Research Foundation Subgrant No. L300060, Project RF-2500-95, Sept. 1995.
** McDowell, Hunter L.,”Magnetron Simulation Using a Moving Wavelength Computer Code,”IEEE Trans. Plasma Science, Vol. 26, No. 3, pp.733-754, June 1998.
300-1000 W
3.35-3.85 kV ~ 300mA
~ 1 W
-20dB
~ 30 dB Gain
-50 dB
Notes: By not powering themagnetron, the low powerlevel RF driver signal canbe reflected through thecirculator to the antenna,yielding a two-level unit.
Filament turned off afterstart for clean spectrum**.
~ 2-3 W
~10 mW~ 1/3500 V/W
0.0024 H, 8.6 Ohms
~ 75% Efficient
ASIC/MMICNeeds Developing
Richard M. Dickinson, JPL
31
Slotted Waveguide Subarray Low Cost Manufacture(With Built In Filtering and Multipaction Inhibiting)
Concept by Bill Brown[1]
..... ..... .....
..... ..... .....
PunchRegistration
Cut Tab Relief
BendTab
Form Inter-W/G Wall
Punch RadiatingWaveguide Slots
FormEnd Walls
Heavy Reynolds Wrap or Equiv. Aluminum Sheet Stock
Integrate Halves &Spot Weld Assy.
Add Feed Guide-Filter to Assy. with Magnetron Flange
1. Brown, W. C.,”Microwave Beamed Power Technology Development,” Final Report JPL Contract No. 955104, Raytheon PT-5613, May 15, 1980.
PunchRegistration
8-Slot X 8-StickW/G Subarray
(front view)W/G TOOLING NEEDS TO BE DEVELOPED!
(back view)
Dielectric Cladding
Richard M. Dickinson, JPL
32
WIRELESS POWER TRANSMISSION NEEDS
I. In order to obtain a service definition and frequency allocation for SSP use, it will benecessary to show the ITU that the SSP can be designed and maintained ElectromagneticallyCompatible with other users of the Radio Spectrum.
II. Because of the GW power levels and the rain of electromagnetic energy falling to Earthfrom a fleet of SSP spacecraft functioning under various operational and environmentalconditions, it is required to filter the carrier noise outside the ISM band, to filter the harmonics, to provide notch filters on the spacecraft and possibly on ground radio andradar equipment functioning at certain sensitive frequencies outside the ISM bands. III. There still exist large uncertainties in the WPT performance and the cost impacts due tothe lack of analysis, measurements, models and victim susceptibility data for determiningthe SSP Electromagnetic Compatibility (EMC) requirements.
IV. Furthermore, a functioning WPT facility does not now exist to validate the adequacyof mitigation approaches or the costs both economically and in filters insertion loss required to achieve EMC both on the transmitters and on the rectennas.
V. Will careful engineering design be economically affordable and adequate to preventserious interference to other users of the electromagnetic Spectrum?
Richard M. Dickinson, JPL
33
SPS Microwave Beam is Safe.
• Wireless Power Transmission was first demonstrated at Goldstone, Ca. in 1975.
• Many years of medical tests have shown that microwaves do not harm people, animals or plants unless they are strong enough to actually heat tissue like a microwave oven.
• However, the SPS beam is only 1/4 as strong as sunlight, too weak to hurt anything.
• The beam also uses a frequency that minimizes heating of water (such as raindrops).
34
State-of-the Art PV R&D
• Commercial cells– Typically only 50-80% of these values
University of Maine
Boeing
Boeing
Boeing
BoeingARCO
NREL
Boeing
Euro-CIS
200019951990198519801975
NREL/Spectrolab
NRELNREL
JapanEnergy
Spire
No. CarolinaState University
Multijunction ConcentratorsThree-junction (2 -terminal, monolithic)Two -junction (2 -terminal, monolithic)
Crystalline Si CellsSingle crystalMulticrystallineThin Si
Thin Film TechnologiesCu(In,Ga )Se2CdTeAmorphous Si:H (stabilized)
Emerging PVOrganic cells Varian
RCA
Solarex
UNSW
UNSW
ARCO
UNSWUNSW
UNSWSpire Stanford
Westing -house
UNSWGeorgia TechGeorgia Tech Sharp
AstroPower
NREL
AstroPower
Spectrolab
NREL
Masushita MonosolarKodak
Kodak
AMETEK
PhotonEnergy
UniversitySo. Florida
NREL
NREL
Princeton UniversityKonstanz
NREL
NRELCu(In,Ga )Se2
14x concentration
NREL
UnitedSolar
United Solar
RCA
RCARCA
RCA RCARCA
Spectrolab
University CaliforniaBerkeley
Solarex12
8
4
0
16
20
24
28
32
36
Best Research -Cell Efficiencies
Efficiency (%)
026587136
Research: “Champion Research: “Champion cells”cells”
• Near 25% efficiency in crystalline silicon and high-efficiency processing
• Rapid thermal processing
• Record efficiencies in CIGS (19.2%); CdTe (16.5%)
• Three-junction GaInP2/GaAs/Ge cell with >35% efficiency
• At up to 400 suns• New PV technologies
emerging• Dye-sensitized cells (up
to 11%)• Organic and polymer
cells (3-4%)• Nanostructured
35
PV R&D Needs
• Two main directions for PV technology development– Ultra high efficiency cells:
• Efficiency target: > 40%
– Low-cost, large scale production cells:• Minimum efficiency target: 15%
• Additional needs:– High voltage cells– High temperature cells– Large deployable arrays
• Both rigid and flexible technologies
36
TRL Status of Advanced Solar Cell/ArraysOhmic contacts
AR coatingP-type cap
Quantum Dots
N-type cap
Ohmic contact
Ohmic contacts
AR coatingP-type cap
Quantum Dots
N-type cap
Ohmic contact
Phoenix Ultraflex Array ( 100 Wh/kg)TJ Cells ( 27% eff)
TRL 6-7
MRO Rigid Panel Array (60 W/kg)TJ Cells ( 27% eff)
TRL 8-9
NM ST-8 Ultraflex Array ( 180 Wh/kg)TJ Cells ( 28% eff)
TRL 5
Quantum dot Solar CellsEff (> 40%)
TRL 1-2
Four Junction solar Cells Eff (> 35 %)
Experimental .CellsTRL 2-3
TJ Cells ( 27% eff)In production
TRL4
37
www.aec-able.comTel: 805.685.2262Fax: 805.685.1369
Able Engineering CompanyCorporate Headquarters, 7200 Hollister Ave., Goleta, CA 93117
Advanced Array Designs
UltraFlex CellSaver
SquareRigger
FTFPV Solar Array
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SSP Robotics Challenges• Major Barriers
– Scale of SSP Systems• hundreds of autonomous agents• multiple kilometer structure to assemble and maintain• millions of individual elements that may need to be replaced or repaired
– Ability to conduct continuous operations over two decades – Ability to conduct maintenance during continuous operations– Force Rejection/ Balancing during materiel movement and placement in micro g environment – Knowledge regarding how EM, thermal and constrained access SSP environmental issues affect
robot operating conditions
• Technology Needed to bring to Reality– Coordinated multiple autonomous robotic platforms– Ability for robotic systems to reconfigure themselves and adapt to changing tasks– New and/or unique robot physiologies– How to walk/manipulate softly– Smart mechanization– Intelligent systems and platform for continuous diagnostics– Hierarchy of robot and platform state assessment
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Challenges to Traditional Approach for Autonomy and Robotics
• Competitive pressures are moving robotic manufacturing and assembly toward shorter product cycles, lower inventories, higher equipment utilization, and shorter lead times, as a result scheduling and control gained priority.
• Scheduling and control has been a process of command and response that relies heavily on hierarchical models.
• Centralization leads to complexity: The control software must handle the entire system and anticipate every circumstance than can arise. Changes in the configuration of the system require changes in the control software. The central computer and database are a bottleneck that can limit the capacity of the performance , and constitute a single point failure that can bring down the entire facility.
• Hierarchy also leads to complexity: Hierarchical control schemes bind workstations into groupings that are difficult to change as the system operates. The hierarchical rule of information flow through supervisors means that naturally occurring lateral information flows are often duplicated, leading to needless redundancy and the possibility of inconsistency between the two versions
N. Marzwell
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SSP Robotics Roadmap• Development for Next Year
– Initiate experiments in heterogeneous, multiple platform cooperative activities, for example, simultaneous cooperative operation of LEMUR and Skyworker
– Development of smart mechanization and structures
• Needed in 2 Years to Bring Space Based Construction a Reality– Integrated technology demonstration showing autonomous grasp and locomotion of antenna
elements– Integrated technology demonstration of mating tasks with two multifunctional cooperative systems– Proof of concept materiel mobility with disturbance rejection– Demonstrate strategies for operations in off - lighting conditions– Simulation and visualization of assembly activity
• Needed in 5 Years To Bring Space Based Construction a Reality– Demonstrate payload balancing with multiple agents– Integrated technology demonstration of cooperative attachment and inspection operations with
robust control – Demonstration mobility with payload interaction for expanding structure in testbed– Refinement of rejection of disturbance forces for low stiffness structures– Refined vision system for speed and anomaly rejection
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Near Term Flight DemonstrationPurpose: A near term flight experiment that demonstrates the
key SSP operations of panel placement, localization and assembly to build and inspect a segmented transmitter array
Approach: • Use an advanced LEMUR configuration and a modified
MPL Robotic Arms for grappling and locomotion of simulated transmitter segments that incorporate smart mechanization for assembly operations
• Utilize a Hitchhiker carrier pallet through STS Small Packages Program. Operations will be conducted within self-contained contained structure to simulate SPP activities
Will Demonstrate:• Materiel movement with MPL robotic arm• LEMUR providing stand-off visual sensing for robotic arm • LEMUR conducting fastening, asssembly and inspection
operations• Cooperative robotics between two systems• Semi-autonomous operations• Mobility and materiel movement in micro-g
Budget•Year 1 $ 3 Million•Year 2 $ 4.5 Million•Year 3 $ 6 Million•Pallet Cost: $1.5 Million
Side walls removed for clarity, full extension of pallet work area not shown
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SSP Robotics Roadmap
• Needed in 10 years– Flight demonstration of
multiple robotic systems conducting assembly operations
– Large scale cooperative systems that demonstrate payload exchange handling and assembly
– Adaptation and learning for unknown payloads and disturbances and failure compensation
Sky worker and LEMUR working cooperatively to assemble, inspect, and conduct maintenance on a SSP structure
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Scaling It Up to 300 GW• The US has a Base Load of over 300 GW.
• A Base-Load Solar Power System providing 300 GW would require storage reservoirs totaling 1/3 the Area of Lake Erie.
• The Collector Site would cover an area of ~90,000 km sq. or 30% the area of Arizona.
• It would cost about 10 trillion dollars and weight about 1 billion tons.
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Est. Cost: One 10-GW SPS breakdown (use advanced R.L.V.)
• Fabrication of SPS modules - 5 Billion
• Construction of Rectenna - 5 Billion
• Launch Components to LEO* - 3 Billion
• Transport to GEO & Deploy - 2 Billion
TOTAL COST ~ 2030 AD - 15 Billion
* Using 40% efficient solar film - Total Mass = 12,500 tons
launch via Reusable Launch Vehicle @ ~ $220 / kg.
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Global Warming Fix Methods: Cost Comparisons for 2030 AD
• Kyoto (partial) ground source ~ $ 40 trillion
• Complete* ground sources ~ $176 trillion
• Complete* SPS- shuttle, etc ~ $463 trillion
• Complete* SPS - adv. RLV ~ $ 18 trillion• Complete* SPS via Elevator ~ $ 14 trillion
* Assume a complete fix requires ~ 18,000 GW, using 40% efficient film on ground & in space. Global Economy in 2030 ~ $80 Trillion / year.
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Capabilities and Challenges Security & the Space Solar Power Option
• Space Based Solar Power (SBSP) is an attractive long-term technology option that involves a compelling synergy between Energy Security, Space Security, and National Security
• Japan, China, India & EU already see the potential• The most significant technical challenges are the
development of – Low-cost re-usable space access– Demonstration of space-to-Earth power beaming– Efficient and light space-qualified solar arrays– Space Assembly, Maintenance and Servicing, and– Large in-space structures
• These are in areas that already interest the DoD and others – and with modest departures to current R&D efforts could retire many of the technical barriers to Space-Based Solar Power
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DoD, National, and International ImpactProposed Vision & Objectives of Space Solar Power
Assured U.S. Preeminence in Space Access and Operations through Dramatic Advances in Transformational Space
Capabilities
Innovation that Creates Novel Technologies and
Systems Enabling New, Highly Profitable Industries on Earth
and in Space
Assured Energy Security for the U.S. and Its Allies through Affordable & Abundant
Space Solar Power with First Power within 25 years
- VISION -The United States and
Partners enable – within the next 20 years – the
development and deployment of affordable Space Solar Power systems that assure the long-term, sustainable energy security of the U.S.
and all mankind
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Where Should We Begin?…how to evolve?
A Candidate “New Start” for the NationRenewed Study of SSPS…why: To assess ROI for economy, health benefit, security, prevent terrorism
• Solar Powered Blips for Communication, Climate Monitoring, Surveillance, local/regional power to developing regions
• Validation of Concept, architecture and financial model for a Modular Reconfigurable High Energy Power System (MRHE)…payoff to ground and space industries and revenues for global economy
• Power for Space Transportation• Power for Space Infrastructure (L1, L5, etc)• Power for Robotic Lunar Exploration and Space Business
Development
Where can we be much later?• Robotic Lunar Exploration - A NASA “New Start”
• Produce propellants from lunar ice and / or regolith (LO2 is over 85% of propellant mass)
- Produce metals for use in construction
- Produce regolith paving & blocks for construction
- Produce photovoltaic power supplies in space and on the Moon (Space Station, Hotels, Spacecrafts, Propulsion)
- Conduct microwave beaming to Earth, Moon and Beyond
- Build an infra-structure for autonomous deployment and robotic assembly supported by future supervised human crews
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How Should We Start?
• Renew Study of Solar Power Satellite (SPS)– Update the 30 years old baseline
• Demonstrate broadly distributed RF transmitters and the much longer range transmission of power
• Reflect present & projected future economics• Involve new expertise from construction &
energy industries• We can save our planet from “peak oil” and
“global warming” if we hurry
•Let’s do something!