Over the Horizon Wireless Power Transmission (OTH-WPT)

Transcription

1 Over the Horizon Wireless Power Transmission (OTH-WPT) A Low Cost Precursor for Space Solar Power Stephen Blank, IBE Systems & NYIT Paul Jaffe, NRL

2 Overview Background Laser SSP Concepts Laser Power Beaming Demonstrations SSP Concepts with High-Altitude Elements Proposed Terrestrial Demonstration Configurations Challenges

3 Selected Laser SSP Concepts EADS Astrium Concept, circa 2010 JAXA Concept, circa 2011 Aerospace Corp. Laser Concept, circa 2002

4 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

5 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 Demonstrated Transmitter Conversion Efficiency Demonstrated Receiver Conversion Efficiency 3.2 km on earth 40 m ~80% ~30% ~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

6 Selected High Altitude Receiving Platform SSP Concepts C.A. Schafer, D. Gray, "Transmission media appropriate lasermicrowave solar power satellite system", Acta Astronautica 79 (2012) S. Blank, S. Leete, P. Jaffe, Feasibility Study of Space Based Solar Power to Tethered Aerostat Systems, IEEE Aerospace Conf 2013

7 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

8 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

9 Demonstration Configuration

10 Demonstration Configuration Functional Block Diagram Laser Power Converter Panel Trihedral Reflector Panel Aerostat or Airborne Platform Pilot Signal Beam Path Tether Power Supply Detector Laser Control Electronics Ground Location 1 Steering Mirror Power Conditioning & Distribution Ground Location 2

11 Demonstration Configuration Range Range as a function of air platform height (km) 300 r( h) h

12 Demonstration Configuration Advantages: Atmospheric attenuation one direction only Power easily sent to multiple locations Disadvantages: Requires tether Potential radiation hazard Converter Panels Power Down Tether Notes: Airship altitudes above troposphere Transmitter

13 Airborne Reflector Configuration Advantages: One airship No tethers Disadvantages: Atmospheric attenuation both directions Potential radiation hazard Reflector Note: Tether could be used with airship if desired. Transmitter Converter Panels

14 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 Transmitter Power Up Tether Converter Panels

15 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 Converter Panels Transmitter Power Down Tether Notes: Airship altitudes above troposphere Power Up Tether

16 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.

17 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

18 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

19 Thank You Stephen Blank, PhD, IBE Systems Corp. and New York Institute of Technology, Paul Jaffe, NRL,

20 Backup

21 Lighter Than Air (LTA) Aerostats Heavy Lift High Altitude Airships ABC A60 56K ISIS 4.2M TowTech HALE-D PTDS 74K TARS 420K SkyTug MA-3 Zeppelin HAA Star Tower LEMV GNSS 40K to 80K ILC Dover Proprietary Information Lightship

22 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.

23 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,

24 What is Proposed? Long Range Wireless Power Beaming using a ground-based high-power laser and a highaltitude 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

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

26 Tethered Aerostat with ground station

27 Tether properties

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

29 Demonstration Configuration Advantages: Atmospheric attenuation one direction only Power easily sent to multiple locations Disadvantages: Requires tether Potential radiation hazard Notes: Airship altitudes above troposphere Converter Panels Transmitter Power Down Tether

30 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)