High-powered laser for refueling aircraft
Moving military units from theater to theater is a challenge for the military’s lift capabilities; an integral part of such capabilities is the ability to refuel aircraft in mid-flight, which is dangerous; researchers offer a way to use laser to recharge the plane’s batteries; for now the system is limited to surveillance UAVs, but the developers envision it being used for larger planes
Both the current U.S. secretary of defense Bob Gates, and his predecessor Donald Rumsfeld, emphasized the need to change the U.S. military from a heavy organization relying on large weapon systems to a light, nimble outfit capable of moving small units from one theater to another. This transformation is required by the changing nature of war — from large armored formations sweeping across the planes of Europe to low-intensity warfare and urban combat required by the need to address the terrorist challenge. Transporting military units and equipment to the far corners of the world is a challenge for the U.S. military’s “lift” capabilities — and an integral part of such capabilities is the ability to refuel planes in mid-air.
New Scientist correctly points out that a fundamental problem with aircraft is the amount of fuel they have to carry. Plane designers are forced to make compromises to reduce fuel consumption and to squeeze the necessarily large fuel tanks into the craft. All this drives up cost and reduces maneuverability. One alternative is in-flight refueling, but that can be logistically difficult as well as dangerous, requiring to aircraft to meet in mid-air and transfer liquid fuel via a flexible hose.
Cleveland State University’s Taysir Nayfeh and colleagues offer a solution: they have devised a way of refueling aircraft using a high-powered laser to recharge on-board batteries (see complete laser aircraft refueling patent application). The team says the aircraft would be fitted with panels capable of converting up to 60 percent of the laser light that hits them into electricity. A single ground-based laser could then keep numerous aircraft airborne indefinitely. The most obvious use would be for light UAV used for surveillance aircraft, but with improved laser and battery technology, larger craft could be kept aloft.
The team notes that a similar idea could be used to refuel spacecraft, but only if a way could be found to dissipate the excess heat that the light-converting panels would generate — not an easy problem in space where there is no atmosphere to carry it away.
