Over the Horizon Wireless Power Transmission (OTH-WPT) OTH WPT 2013 IEEE SSP Baltimore...Over the...

Over the Horizon Wireless Power Transmission (OTH-WPT)

A Low Cost Precursor for Space Solar Power

Stephen Blank, IBE Systems & NYIT

Paul Jaffe, NRL

Overview

• Background

– Laser SSP Concepts

– Laser Power Beaming Demonstrations

– SSP Concepts with High-Altitude Elements

• Proposed Terrestrial Demonstration

– Configurations

– Challenges

Selected Laser SSP Concepts

Aerospace Corp. Laser Concept, circa 2002

JAXA Concept, circa 2011

EADS Astrium Concept, circa 2010

Selected Laser Power Beaming Demonstrations

EADS Astrium tracking laser to power rover, circa 2003

Kinki Univ. & Hamamatsu Photonics Inc. laser power to small helicopter, circa 2007

Lasermotive outdoor laser power to UAV, circa 2012

Comparison of Microwave and Laser Power Transmission for SSP from GEO

Microwave Laser

Transmit frequency 5.8 GHz 1.4 mm

Transmit Aperture Diameter In GEO 1 km 2.5 m

Receiving Aperture Diameter On or Near Earth

3.2 km on earth 40 m

Demonstrated Transmitter Conversion Efficiency

~80% ~30%

Demonstrated Receiver Conversion Efficiency

~90% ~50%

Vulnerability to Weather Probably negligible Not negligible*

Spectrum Allocation Challenges Likely to be high ?

International Political Challenges ? Likely to be high*

*this problem may be reduced or eliminated by using a high altitude receiving platform

Selected High Altitude Receiving Platform SSP Concepts

C.A. Schafer, D. Gray, "Transmission media appropriate laser-microwave solar power satellite system", Acta Astronautica 79 (2012) 140–156

S. Blank, S. Leete, P. Jaffe, “Feasibility Study of Space Based Solar Power to Tethered Aerostat Systems”, IEEE Aerospace Conf 2013

Space to Tethered Aerostat SSP

• Beaming from space to a high altitude tethered aerostat avoids main effects of atmospheric attenuation

• Potentially allows use of “eye-safe” laser transmit frequency which results in far smaller apertures vs. microwave for: transmit antenna in GEO and receive aperture on the aerostat

Demonstration Motivation

• The high cost of getting to space has been an obstacle to demonstration implementations

• Over the Horizon Wireless Power Transmission, OTH-WPT, is proposed as a low cost precursor to SSP that does not require access to space

“...large-scale demonstration of power beaming is a necessary step to the development

of solar power satellites.” – Geoffrey Landis, scientist and author

Demonstration Configuration

Ground Location 2

Ground Location 1

Aerostat or Airborne

Platform

Demonstration Configuration Functional Block Diagram

Laser

Laser Power Converter Panel

Power Conditioning

& Distribution Power Supply

Trihedral Reflector Panel

Beam Path

Steering Mirror

Detector

Pilot Signal

Control Electronics

Tether

Demonstration Configuration Range

Range as a function of air platform height (km)

2 4 6 8 100

100

200

300

r h( )

h

Power Down Tether

Converter Panels

Notes: Airship altitudes above troposphere

Demonstration Configuration • Advantages:

• Atmospheric attenuation one direction only •Power easily sent to multiple locations

• Disadvantages: • Requires tether • Potential radiation hazard

Transmitter

Airborne Reflector Configuration • Advantages:

• One airship • No tethers

• Disadvantages: • Atmospheric attenuation both directions • Potential radiation hazard

Transmitter

Reflector

Converter Panels

Note: Tether could be used with airship if desired.

Power Beam Down Configuration • Advantages:

• Atmospheric attenuation one direction only • Power easily sent to multiple locations • Easier logistics at receiving site

• Disadvantages: • Requires tether • Potential radiation hazard

Power Up

Tether

Converter Panels

Transmitter

Beam at Altitude Configuration • Advantages:

• Minimizes atmospheric attenuation • Very long range, potentially > 1000 km • Power easily sent to multiple locations

• Disadvantages: • Two airships • Requires tethers

Transmitter

Power Down Tether

Converter Panels

Notes: Airship altitudes above troposphere Power

Up Tether

Design Challenges

• Airborne/field deployable high power lasers • Beam pointing, tracking, retro-directivity • Compensating for atmospheric effects • Mirrors for high power lasers • Laser power conversion • Laser radiation safety • Air platform: high altitude, long duration* • Tether: light weight, low resistance, high voltage • Air traffic control * Aerostats currently operate at 4-5 km with up to 90

mph wind survivability.

Hardware Sources • High power lasers:

– IPG Photonics

– Teradiode

• Beam Control:

– Adaptive Optics / Northrop Grumman

– Boeing

– Lasermotive

– Lighthouse Development

• Aerostats:

– ILC Dover

– T-com

• Laser energy conversion:

– Spectrolab

– JX Crystals

OTH-WPT Goal & Conclusion

• Provide deployable, portable, long range, economical power transmission for security, commercial, and civil applications

• Over the Horizon Wireless Power Transmission represents an achievable, low-cost precursor for Space Solar Power

Thank You

• Stephen Blank, PhD, IBE Systems Corp. and New York Institute of Technology, sblank@nyit.edu , sblank@ibesystems.com

• Paul Jaffe, NRL, paul.jaffe@nrl.navy.mil

Backup

Lighter Than Air (LTA)

56K

PTDS 74K

TARS 420K Zeppelin

ABC A60

HALE-D

SkyTug

ISIS

Aerostats High Altitude Airships

4.2M TowTech

Heavy Lift

Lightship

HAA

MA-3

GNSS 40K to 80K

StarTower

LEMV

ILC Dover Proprietary Information

Technical Issues

• The amount of loss along the tether during the transmission of the electrical power to the ground is an important technical issue.

• This loss can be reduced through the use of a low resistivity conductor and the choice of a high voltage for transmission.

Technical Issues

• Clouds can occur at operational altitudes.

• Statistical analysis of meteorological data show that the probability of occurrence decreases with altitude and is not statically significant at altitudes above 6 km.

• ref: i) Chilbolton Observatory, UK

ii) Cloudnet, 2007, http://www.cloud-net.org/

What is Proposed?

• Long Range Wireless Power Beaming using a ground-based high-power laser and a high-altitude receiving platform

• 100s of km range

• Delivery of 100s of kW electric power

• Many other configurations are possible to meet variety of range, power, weather and tactical needs

Tethered Aerostats widely used, mfg. in the U.S.

Tethered Aerostat with ground station

Tether properties

Aerostats, widely used, U.S. mfg. items.

Power Down Tether

Converter Panels

Notes: Airship altitudes above troposphere

Demonstration Configuration • Advantages:

• Atmospheric attenuation one direction only •Power easily sent to multiple locations

• Disadvantages: • Requires tether • Potential radiation hazard

Transmitter

Radiation Safety

• Interlocking intrusion control

• Beam pointing positive control

• Power density limitations

• Wavelength choice to minimize potential radiation hazard to personnel, animals and equipment, (1.5 mm, eye-safe)