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Stationary High Altitude Relay Platform
SHARP, short for Stationary High Altitude Relay Platform, was an experimental aircraft using beam-powered propulsion designed by the Communications Research Centre Canada (CRC) and built by the University of Toronto Institute for Aerospace Studies (UTIAS) during the 1980s. SHARP used microwaves to provide energy from a ground station that powered electric motors spinning propellers to keep the aircraft aloft. The power was also used for the onboard electronics. SHARP could remain aloft indefinitely, and was intended to be used as a sort of low-altitude communications satellite for smaller geographical areas. History Background The concept of using beamed power for aircraft propulsion was invented almost single-handedly by William C. Brown. After joining Raytheon in the 1940s, Brown started work on improving their magnetron products. This led to the development of the crossed-field amplifier, a simple, reliable and highly efficient microwave amplifier. He later worked with colleague ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam-powered Propulsion
Beam-powered propulsion, also known as directed energy propulsion, is a class of aircraft or spacecraft propulsion that uses energy beamed to the spacecraft from a remote power plant to provide energy. The beam is typically either a microwave or a laser beam and it is either pulsed or continuous. A continuous beam lends itself to thermal rockets, photonic thrusters and light sails, whereas a pulsed beam lends itself to ablative thrusters and pulse detonation engines. The rule of thumb that is usually quoted is that it takes a megawatt of power beamed to a vehicle per kg of payload while it is being accelerated to permit it to reach low earth orbit. Other than launching to orbit, applications for moving around the world quickly have also been proposed. Background Rockets are momentum machines; they use mass ejected from the rocket to provide momentum to the rocket. Momentum is the product of mass and velocity, so rockets generally attempt to put as much velocity into their worki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with an artwork pattern of traces, planes and other features (similar to wires on a flat surface) etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds vias: plated-through holes that allow interconnections between layers. Printed circuit boards are used in nearly all electronic products. Alternatives to PCBs include wire wrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
