Ariadna Call for Ideas 2011: Innovative Wireless Power Transmission

Type of activity: Standard study (25 k€)
Deadline of application: 06 March 2012

Background and motivation

Wireless power transmission for space – general interest

Wireless power transmission (WPT) is of inherent interest for some space applications and would enable others. However, due to its still relatively low maturity (range, efficiency, specific power etc) its development and application has been limited so far. A non-exhaustive list of such applications of WPT is given below:
- Fractionated spacecraft: the concept of fractionated spacecraft is based on splitting a S/C into its major subsystems and put them into smaller spacecraft flying in formation, each dedicated one subsystem. One (or more) of this smaller spacecraft would be dedicated to electrical power subsystem and would generate and transmit power efficiently and wirelessly to the others. In this way, it would make the maintenance and servicing easier and increase the robustness of the system. [1]-[3].
- Planetary remote power: Lunar, Martian and planetary exploration missions often rely on rovers or even ground bases. To avoid energy storage during long night phases and/or shadowing phases during crater exploration, WPT could be very useful in remotely powering rovers and ground bases from either ground or orbiting solar generator platforms [4]-[6].
- Space elevator: the space elevator concept would allow a payload to be launched into orbit much more efficiently through a platform that would crawl along a tether and lift the payload to space. In order to crawl along the tether, the platform would be remotely powered through wireless power transmission [6].
- Wireless propulsion: both laser and microwave have been proposed as a means to transmit energy to small launch vehicles, where it would be used to perform useful work [7].
- Reducing harness: wireless power transmission has been proposed to reduce the needs for cables and electric contacts on spacecraft (e.g. sensors) as well as in ground in testing environments
- Solar Power Satellites (SPS): with the growing population and energy demand, new alternative renewable energy sources must be developed. In 1968, P. Glaser [8] re-introduced the concept already mentioned by K. Tsiolkovsky in 1925 consisting of large space structures collecting solar energy in space 24/7 and beaming it down to earth as a reliable and renewable energy source. Wireless power transmission is therefore one of the key technologies driving the SPS concept.

From theoretical ideas to state of the art WPT concepts

First theoretically predicted by Maxwell in his “A Treatise on Electricity and Magnetism” in 1873 and later confirmed by Hertz with his experiments on radio waves, wireless power transmission has then been illustrated and strongly advocated in the early 20th century by Nikola Tesla [9] who wirelessly powered light bulbs in his experiments in 1899 at Colorado Springs [10], [11]. However, wireless power transmission suffered of lack of interest for the following 40 years. Only with the invention of the magnetron in 1939 [12], the development of radar during the second World War and the invention of the rectennas in the 1960s, did the industrial and defence interest for wireless microwave power transmission materialised. First experiments, e.g. microwave powered helicopter [13], led in 1968 to the first engineering proposal for a solar power satellite and subsequent studies with substantial funding during the 1970s. Within that framework, a high power microwave transmission experiment was conducted by Raytheon under the supervision of JPL at the Goldstone facility in 1975, achieving 30kW CW output power over a distance of 1.55km with >80% rectifying efficiency [14].
Today, the efficiency of microwave ovens magnetrons is approximatly 70% [15] with specific magnetron development increasing the performance to 87% while rectenna (for rectifying antenna) efficiency is also about 85 to 90% [16].
Instead of using far field, near field wireless power transmission is also researched, not at least thanks to its increasing use in home appliances, mobile electronic devices and gadgets. Recent research has demonstrated the principal possibility to extend its inherent shorter range. It could therefore be of interest for some applications such as fractionated spacecraft, onboard energy transmission or implantable devices.

In parallel to RF wireless power transmission, optical WPT appeared with the first laser operated by Theodore Maiman in 1960 along with the development of solar cells. The inherent collimation of laser allows smaller beam size, making them attractive in specific applications. Compared to microwave wireless power transmission, laser WPT still has lower overall efficiencies, though continuous improvements on its key technologies have been reported (high efficiency pumping laser diodes [17] [18] and high efficiency, high density monochromatic solar cells [19],[20]).
Laser power transmission has also been promoted by the space elevator challenge [6]. Within that framework, the Beam Power Challenge is a competition to build a wirelessly-powered ribbon-climbing robot. In the 2009 edition, LaserMotive won the competition for building a laser powered robot climbing along a tether up to 900m at the average speed of almost 4m/s [21][22].
Direct solar pumping laser has also been studied in the last decades. Direct solar pumping offers the advantage of avoiding the need for the electricity conversion step. Recent advances have increased the optical-to-optical efficiency up to more than 30% [23], [24] and even 60% using phonon assisted cross-relaxation in Cr3+:Nd3+:YAG [25].
Alternative ways of transmitting power wirelessly have been studied [26], [27]. JPL for instance studied the propagation of acoustic waves through a S/C structure to provide with energy a sealed compartment for contamination purposes. The acoustic wave was generated and converted back to electricity through piezoelectric transducers [28].
The principal working mechanisms and options for both, WPT via laser and via microwaves are schematically represented in Figure 1.

Research and Study Objectives

In order to enable some of the applications listed above and allow WPT to be competitive with alternatives for some others, substantial, possibly order-of-magnitude improvements to one or more of its key parameters (mass, efficiency, transmission distances (e.g. diffraction limits), power levels) is necessary.
Additionally, only relatively small resources and few research teams have been working on wireless power transmission concepts and technologies, mainly on the two concepts (WPT via laser and microwave).
The objective of this call for idea is therefore to perform research on either:

- alternative, new concepts for transmitting power wirelessly, or
- innovative ways to substantially (typically 5 times to one order of magnitude or more) improve already described WPT concepts; substantial improvements need to be in one of the key parameters listed above. Small, incremental improvements are not targeted by this call.

In principle, all scientific fields of potential relevance are encouraged to propose solutions.

Study Proposals

Study proposals should contain

1. the description of the general idea, including its physical basis

2. how the concept/idea can either substantially improve the state of the art or is different to already described ones

3. a proposed research step that addresses and matures a key aspect of the concepts

All proposals need to be based and explained within the current standard model of physics. Identification of possible space applications are encouraged.
The proposed research scope needs to be feasible within the Ariadna study framework (www.esa.int/ariadna).
Proposers are strongly encouraged to underline their reasoning with references to published papers and research results.
For the selected concepts or techniques, the first proposed research step shall be performed during the study.

References

[1] O. Brown and P. Eremenko, The value proposition for fractionated space architectures, In Proceedings AIAA 2006, 2006.

[2] P. Molette, C. Cougnet P. Saint-Aubert, R. Young, D. Helas, Technical and Economical Comparison Between a Modular Geostationary Space Platform and a Cluster of Satellites, Acta Astronautica 12 (11), 1984, pp.771–784

[3] D. Barker, L. Summerer, Assessment of near field wireless power transmission for fractionated spacecraft applications, In 62nd International Astronautical Congress, Cape Town, South Africa, IAC-11-C3.2.7, 2011

[4] L. Torres-Soto, L. Summerer, Power to survive the Lunar night: an SPS application?, In 59th International Astronautical Congress, Glasgow, Scotland, IAC-08-C.3.1.2, 2008

[5] C. Cougnet, E. Sein, A. Celeste, L. Summerer, Solar power satellites for space exploration. In 55th International Astronautical Congress, Vancouver, Canada, IAC-04-R-3-06 2004.

[6] H. Brandhorst, POWOW — an alternative power source for Mars exploration, Acta Astronautica, vol. 51, pp. 57-62, Nov. 2002.

[7] The Spaceward Foundation, http://www.spaceward.org/, accessed on Nov. 11th, 2011.

[8] Komatsu R, Fukunari M, Yamaguchi T, Komurasaki K, Arakawa Y, Oda Y, et al. Development of Microwave Rocket as a space mass transportation system. IEEE 2011. p. 185–8.

[9] P. Glaser, Power from the sun: Its future, Science,162:856–861, 1968.

[10] N. Tesla, The transmission of electrical energy without wires. Electrical World and Engineer. 1904 March 5.

[11] W.C. Brown, The History of Power Transmission by Radio Waves, Microwave Theory and Techniques, IEEE Transactions on, Vol.32, no.9, pp.1230-1242, Sep. 1984

[12] W.C. Brown, The history of wireless power transmission, Solar Energy, Vol.56, Iss. 1, pp. 3-21, Jan. 1996

[13] H.A.H. Boot, J.T. Randall, Historical notes on the cavity magnetron, Electron Devices, IEEE Transactions on, Vol.23, no.7, pp.724-729, Jul. 1976

[14] W. C. Brown, "Experiments involving a microwave beam to power and position a helicopter," IEEE Transactions on Aerospace Electronic Systems, vol. AES-5, no. 5, pp. 692-702, Sept. 1969.

[15] R.M. Dickinson, Performance of a High-Power, 2.388-GHz Receiving Array in Wireless Power Transmission Over 1.54 km, in Proceedings, Microwave Symposium, 1976 IEEE-MTT-S International, pp.139-141, 14-16 June 1976

[16] T. Mitani, H. Kawasaki, N. Shinohara, H. Matsumoto, A study of oven magnetrons toward a transmitter for space applications, in Proceedings, Vacuum Electronics Conference, 2009. IVEC '09. IEEE International., pp.323-324, 28-30 April 2009

[17] J.O. McSpadden, J.C. Mankins, Space solar power programs and microwave wireless power transmission technology, Microwave Magazine, IEEE , vol.3, no.4, pp. 46-57, Dec 2002

[18] P. Crump, W. Dong, M. Grimshaw, J. Wang, S. Patterson, D. Wise, M. DeFranza, S. Elim, S. Zhang, M. Bougher, J. Patterson, S. Das, J. Bell, J. Farmer, M. DeVito, R. Martinsen, 100-W+ Diode Laser Bars Show > 71% Power Conversion from 790-nm to 1000-nm and Have Clear Route to > 85%, High-Power Diode Laser Technology and Applications V. Edited by Zediker, Mark S.. Proceedings of the SPIE, Vol.6456, pp.64560M (2007).

[19] P. Crump, M. Grimshaw, J. Wang, W. Dong, S. Zhang, S. Das, J. Farmer, M. DeVito, L.S. Meng, J.K. Brasseur, 85% power conversion efficiency 975-nm broad area diode lasers at - 50°C, 76 % at 10°C, Lasers and Electro-Optics, 2006 Quantum Electronics and Laser Science Conference, 2006, pp.1-2, 21-26 May 2006

[20] E. Oliva, F. Dimroth, and A. W. Bett, GaAs converters for high power densities of laser illumination, Progress in Photovoltaics: Research and Applications, vol. 16, no. 4, pp. 289-295, 2008.

[21] A. W. Bett, F. Dimroth, R. Lockenhoff, E. Oliva, and J. Schubert, “III-V solar cells under monochromatic illumination,” 2008, pp. 1-5.

[22] T. Nugent, Technical Overview LaserMotive’s Winning Entry 2009 Space Elevator Games Power Beaming Competition, 2009

[23] NASA website, http://www.nasa.gov/centers/dryden/status_reports/power_beam.html, accessed on Nov. 11th, 2011

[24] T. Saiki, S. Motokoshi, K. Imasaki, M. Nakatsuka, C. Yamanaka, K. Fujioka, H. Fujita, Two-pass amplification of CW laser by Nd/Cr:YAG ceramic Active mirror under lamp light pumping, Optics Communications, Vol.282, (5), 1 March 2009, pp.936-939.

[25] T. Saiki, S. Uchida, S. Motokoshi, K. Imasaki, M. Nakatsuka, H. Nagayama, Y. Saito, M. Niino, M. Mori, Development of Solar-Pumped Lasers For Space Solar Power Station, In Proceedings, IAC-05-C3.4-D2.8.09, International Astronautical Congress, Fukuoka, Japan, Oct. 2005.

[26] T. Saiki, M. Nakatsuka, K. Imasaki, Highly efficient lasing action of Nd3+ and Cr3+-doped Yttrium Aluminum Garnet ceramics based on phonon assisted cross-relaxation using solar light sources, Japanese Journal of Applied Physics 49 (2010), 082702

[27] Y. Shigeta, Y. Hori, K. Fujimori, K. Tsuruta, S. Nogi, Development of highly efficient transducer for wireless power transmission system by ultrasonic, Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications (IMWS), 2011 IEEE MTT-S International, pp.171-174, 12-13 May 2011

[28] Y. Kanno, Y. Kasai, K. Tsuruta, K. Fujimori, H. Fukano, S. Nogi, Acoustic lens using sonic crystal for energy-transmission application, Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications (IMWS), 2011 IEEE MTT-S International, pp.207-210, 12-13 May 2011

[29] S. Sherrit, X. Bao, M. Badescu, J. Aldrich, Y. Bar-Cohen, W. Biederman, and Z. Chang, 1KW Power Transmission using Wireless Acoustic-Electric Feed-through (WAEF), ASCE Conf. Proc. 323, 120 (2008)

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