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Optical Lift
Optical lift is an optical analogue of aerodynamic lift, in which a cambered refractive object with differently shaped top and bottom surfaces experiences a stable transverse lift force when placed in a uniform stream of light. Discovery The ability of light to apply pressure to objects is known as radiation pressure, which was first postulated in 1619 and proven in 1900. This is the principle behind the solar sail, which uses light radiation pressure to move through space. A 2010 study by physicist Grover Swartzlander and colleagues of the Rochester Institute of Technology in Rochester, New York shows light is also capable of creating the more complex force of "lift", which is the force generated by airfoils that make an airplane rise upwards as it travels forward. This study was published in December 2010 in ''Nature Photonics'' journal. Swartzlander predicted, observed and experimentally verified at a micrometer-scale that when applying a beam of laser light to a semi-cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Etymology and usage For many centuries, the word "wing", from the Old Norse ''vængr'', referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Wing Design
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, paramotors, and hot air balloons. The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called ''aeronautics.'' Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Sail
Solar sails (also known as light sails and photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010. A useful analogy to solar sailing may be a sailing boat; the light exerting a force on the mirrors is akin to a sail being blown by the wind. High-energy laser beams could be used as an alternative light source to exert much greater force than would be possible using sunlight, a concept known as beam sailing. Solar sail craft offer the possibility of low-cost operations combined with long operating lifetimes. Since they have few moving parts and use no propellant, they can potentially be used numerous times for delivery of payloads. Solar sails use a phenomenon that has a proven, measured effect on astrodynamics. Solar pressure affec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Force
The optical force is a phenomenon whereby beams of light can attract and repel each other. The force acts along an axis which is perpendicular to the light beams. Because of this, parallel beams can be induced to converge or diverge. The optical force works on a microscopic scale, and cannot currently be detected at larger scales. It was discovered by a team of Yale researchers led by electrical engineer Hong Tang. Discover magazine, from the January–February 2010 special issue; published online December 21, 2009 See also *Optical lift
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Laser Propulsion
Laser propulsion is a form of beam-powered propulsion where the energy source is a remote (usually ground-based) laser system and separate from the reaction mass. This form of propulsion differs from a conventional chemical rocket where both energy and reaction mass come from the solid or liquid propellants carried on board the vehicle. History The basic concepts underlying a photon-propelled "sail" propulsion system were developed by Eugene Sanger and the Hungarian physicist György Marx. Propulsion concepts using laser-energized rockets were developed in the 1970s by Arthur Kantrowitz and Wolfgang Moekel, with a variant using laser ablation pioneered by Leik Myrabo.Myrabo, L.N. 1976MHD propulsion by absorption of laser radiation" ''Journal of Spacecraft and Rockets", Vol. 13, 8, pp. 466–472. doi 10.2514/3.27919 An exposition of Kantrowitz's laser propulsion ideas was published in 1988. Laser propulsion systems may transfer momentum to a spacecraft in two different ways. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IKAROS
IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) is a Japan Aerospace Exploration Agency (JAXA) experimental spacecraft. The spacecraft was launched on 20 May 2010, aboard an H-IIA rocket, together with the ''Akatsuki'' (Venus Climate Orbiter) probe and four other small spacecraft. IKAROS is the first spacecraft to successfully demonstrate solar sail technology in interplanetary space. On 8 December 2010, IKAROS flew by Venus at a distance of , successfully completing its planned mission, and entered its extended operation phase. Purpose The IKAROS probe is the world's first spacecraft to use solar sailing as the main propulsion. It was designed to demonstrate four key technologies (comments in parentheses refer to figure): # Deployment and control of a large, thin solar sail membrane (grey-blue areas numbered 3) # Thin-film solar cells integrated into the sail to power the payload (black rectangles numbered 4) # Measurement of acceleration due to radiatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerodynamic Force
In fluid mechanics, an aerodynamic force is a force exerted on a body by the air (or other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Force There are two causes of aerodynamic force: *the normal force due to the pressure on the surface of the body *the shear force due to the viscosity of the gas, also known as skin friction. Pressure acts normal to the surface, and shear force acts parallel to the surface. Both forces act locally. The net aerodynamic force on the body is equal to the pressure and shear forces integrated over the body's total exposed area. When an airfoil (such as a wing) moves relative to the air, it generates an aerodynamic force in a rearward direction, at an angle determined by the direction of relative motion. This aerodynamic force is commonly resolved into two components, both acting through the center of pressure: *'' drag'' is the force component parallel to the direction of relative mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry. Several methods of pragmatic spacecraft propulsion have been developed each having its own drawbacks and advantages. Most satellites have simple reliable chemical thrusters (often monopropellant rockets) or resistojet rockets for orbital station-keeping and some use momentum wheels for attitude control. Soviet bloc satellites have used electric propulsion for decades, and newer Western geo-orbiting spacecraft are starting to use them for north–south station-keeping and orbit raising. Interplanetary vehicles mostly use chemical rockets as well, although a few have used ion thrusters and Hall-effect thrusters (two different types of electric propulsion) to great success. Hypothetical in-space propulsion technologies describe the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Sails
Solar sails (also known as light sails and photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010. A useful analogy to solar sailing may be a sailing boat; the light exerting a force on the mirrors is akin to a sail being blown by the wind. High-energy laser beams could be used as an alternative light source to exert much greater force than would be possible using sunlight, a concept known as beam sailing. Solar sail craft offer the possibility of low-cost operations combined with long operating lifetimes. Since they have few moving parts and use no propellant, they can potentially be used numerous times for delivery of payloads. Solar sails use a phenomenon that has a proven, measured effect on astrodynamics. Solar pressure affect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagram Of Flying Carpets On Solar Sail
A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the Enlightenment. Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word '' graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In science the term is used in both ways. For example, Anderson (1997) stated more generally: "diagrams are pictorial, yet abstract, representati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
