GEORGE TREUSCH, TOBIAS KOENNING,
AND BEN SHELEF
Power beaming—the wireless transmission of energy from one location to another—has come a long way since Nikola Tesla’s experiments on couple-tuned-circuit oscil-
lators. Although wireless power beaming is less efficient than using a conductor, it lasers and the growing is the only way to power remote locations when laying power lines is not feasible, photovoltaic market have such as when a vehicle climbs 100,000 km accelerated interest in into space from the Earth’s surface—also called the space elevator (see Fig. 1). power beaming (wireless
In 2004 the Spaceward Foundation asked the Centennial Challenges office of power transfer). The NASA- the National Aeronautics and Space Administration (NASA; Washington, D.C.) sponsored Space Elevator to conduct two prize technology challenges on the core technologies that make competition is currently the up the space elevator: very strong tethers and improved power-beaming systems. 1 most popular application of While NASA’s interest in the two com- power beaming. petition topics stems from their useful-
FIGURE 1. An artist’s rendering illustrates the concept of the space elevator, a platform powered by a ground-based laser-diode unit that climbs into space from Earth on a ribbon or tether. (Courtesy of The Spaceward Foundation)
GEORGE TREUSCH is vice president and general manager and TOBIAS KOENNING is a product engineer at DILAS Diode Laser, 9070 South Rita Rd., Suite 1500, Tucson, AZ 85747; e-mail: gtreusch@ dilas-inc.com; www.dilas.com. BEN SHELEF is cofounder and leader of The Spaceward Foundation, 725 N. Shoreline Blvd., Mountain View, CA 94043; www.spaceward.org.
ness in other fields, the two challenges under the “Elevator:2010” umbrella were silently approved at the highest level. The goals in both challenges are incremental technology development, coupled with public awareness and advocacy of the space-elevator concept.
For the 2007 power-beaming challenge of 100 m in 50 s, leading competitors— including returning champions from the University of Saskatchewan (Sas-
katoon, SK, Canada)—chose near-infrared lasers as a power-beaming source because of the material response of the silicon (Si) and gallium arsenide (GaAs) photocell receivers used by the competing teams, as well as the power density. The field of power-beaming applications is wider than the space elevator, however, so other wave-
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