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Solid Rocket
A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/ oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder. The inception of gunpowder rockets in warfare can be credited to the ancient Chinese, and in the 13th century, the Mongols played a pivotal role in facilitating their westward adoption. All rockets used some form of solid or powdered propellant until the 20th century, when liquid-propellant rockets offered more efficient and controllable alternatives. Because of their simplicity and reliability, solid rockets are still used today in military armaments worldwide, model rockets, solid rocket boosters and on larger applications. Since solid-fuel rockets can remain in storage for an extended period without much propellant degradation, and since they almost always launch reliably, they have been frequently used in military applications such as missiles. The lower performance of solid propellants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Columbia Launching
Space is a Three-dimensional space, three-dimensional continuum containing position (geometry), positions and direction (geometry), directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional Continuum (theory), continuum known as ''spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are Non-Euclidean geometry, non-Euclidean, in which space is conceived as ''space curvature, curved'', rather than ''flat space, flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propellant Charge
A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the engine that expels the propellant is called a reaction engine. Although technically a propellant is the reaction mass used to create thrust, the term "propellant" is often used to describe a substance which contains both the reaction mass and the fuel that holds the energy used to accelerate the reaction mass. For example, the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, although the propellants should not be confused with the fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Attitude Control
Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle or satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle attitude requires actuators to apply the torques needed to orient the vehicle to a desired attitude, and algorithms to command the actuators based on the current attitude and specification of a desired attitude. Before and during attitude control can be performed, spacecraft attitude determination must be performed, which requires sensors for absolute or relative measurement. The broader integrated field that studies the combination of sensors, actuators and algorithms is called ''guidance, navigation and control'', which also involves non-attitude concepts, such as position determination and navigation. Motivation A spacecraft's attitude must typically be stabilized and controlled for a variety of reasons. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auxiliary Power Unit
An auxiliary power unit (APU) is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft and naval ships as well as some large land vehicles. Aircraft APUs generally produce 115 V AC voltage at 400 Hz (rather than 50/60 Hz in mains supply), to run the electrical systems of the aircraft; others can produce 28 V DC voltage. APUs can provide power through single or three-phase systems. A jet fuel starter (JFS) is a similar device to an APU but directly linked to the main engine and started by an onboard compressed air bottle. Transport aircraft History During World War I, the British Coastal class blimps, one of several types of airship operated by the Royal Navy, carried a ABC auxiliary engine. These powered a generator for the craft's radio transmitter and, in an emergency, could power an auxiliary air blower. One of the first military fixed-wing aircraft to use an APU was the British, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-destruct
A self-destruct is a mechanism that can cause an object to destroy itself or render itself inoperable after a predefined set of circumstances has occurred. Self-destruct mechanisms are typically found on devices and systems where malfunction could endanger large numbers of people. Uses Land mines Some types of modern land mines are designed to self-destruct, or chemically render themselves inert after a period of weeks or months to reduce the likelihood of friendly casualties during the conflict or civilian casualties after the conflict's end. The Amended Protocol II to the Convention on Certain Conventional Weapons (CCW), amended in 1996, requires that anti-personnel land mines deactivate and self-destruct, and sets standards for both. Landmines currently used by the United States military are designed to self-destruct after between 4 hours and 15 days depending upon the type. The landmines have a battery and when the battery dies, the land mine self-destructs. The self-de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parachute
A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves various purposes like slowing cargo, aiding in space capsule recovery, and stabilizing vehicles or objects. Modern parachutes are typically made from durable fabrics like nylon and come in various shapes, such as dome-shaped, rectangular, and inverted domes, depending on their specific function. The concept of the parachute dates back to ancient attempts at flight. In 852 AD, Armen Firman, in Córdoba, Spain, made the first recorded jump with a large cloak to slow his fall. Renaissance figures like Francesco di Giorgio Martini and Leonardo da Vinci later sketched designs resembling modern parachutes, but it wasn’t until the 18th century that the first successful jumps occurred. French Louis-Sébastien Lenormand made the first public jump i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avionics
Avionics (a portmanteau of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, and the hundreds of systems that are fitted to aircraft to perform individual functions. These can be as simple as a searchlight for a police helicopter or as complicated as the tactical system for an airborne early warning platform. History The term "avionics" was coined in 1949 by Philip J. Klass, senior editor at ''Aviation Week & Space Technology'' magazine as a portmanteau of "aviation electronics". Radio communication was first used in aircraft just prior to World War I. The first Airborne radio relay, airborne radios were in zeppelins, but the military sparked development of light radio sets that could be carried by heavier-than-air craft, so that aerial reconnaissance biplanes could report their observations immediately in case they we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulsed Rocket Motors
A pulsed rocket motor is typically defined as a multiple-Pulse (physics), pulse solid-fuel rocket motor. This design overcomes difficulties shutting down and reigniting solid propellant motors. The pulse rocket motor allows the motor to be burned in segment (rocketry), segments (or pulses) that burn until completion of that segment. The next segment can be ignited on command by either an onboard algorithm or in a pre-planned sequence. All of the segments are contained in a single rocket motor case, as opposed to Multi-stage rocket, staged rocket motors. The pulsed rocket motor is made by pouring each segment of propellant separately. Between each segment is a wiktionary:barrier, barrier that prevents the other segments from burning until ignited. At Combustion, ignition of a second pulse, the burning of the propellant generally destroys the barrier. The benefit of the pulsed rocket motor is that, by the on-command ignition of the subsequent pulses, near-optimal energy mana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throttle
A throttle is a mechanism by which fluid flow is managed by construction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' has come to refer, informally, to any mechanism by which the power or speed of an engine is regulated, such as a car's accelerator pedal. What is often termed a ''throttle'' (in an aviation context) is also called a thrust lever, particularly for jet engine powered aircraft. For a steam locomotive, the valve which controls the steam is known as the regulator. Internal combustion engines In an internal combustion engine, the throttle is a means of controlling an engine's power by regulating the amount of fuel or air entering the engine. In a motor vehicle the control used by the driver to regulate power is sometimes called the throttle, accelerator, or gas pedal. For a gasoline engine, the throttle most commonly regulates the amount of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Engine
A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed Jet (fluid), jet of high-temperature gas produced by the combustion of rocket propellants stored inside the rocket. However, non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum, and they can achieve great speed, beyond escape velocity. Vehicles commonly propelled by rocket engines include missiles, Rocket-assisted projectile, artillery shells, ballistic missiles and rockets of any size, from tiny Rocket (firework), fireworks to Rocket (weapon), man-sized weapons to huge Space vehicle, spaceships. Compared to other types of jet engine, rocket engines are the lightest and have the highest thrust, but are the least propellant-efficient (they have the lowest specific impulse). The ideal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propelling Nozzle
A propelling nozzle or exhaust ejector is a nozzle that converts the internal energy of a working gas into propulsive force; it is the nozzle, which forms a jet, that separates a gas turbine, or gas generator, from a jet engine. Propelling nozzles accelerate the available gas to subsonic, transonic, or supersonic velocities depending on the power setting of the engine, their internal shape and the pressures at entry to, and exit from, the nozzle. The internal shape may be convergent or convergent-divergent (C-D). C-D nozzles can accelerate the jet to supersonic velocities within the divergent section, whereas a convergent nozzle cannot accelerate the jet beyond sonic speed. Propelling nozzles may have a fixed geometry, or they may have variable geometry to give different exit areas to control the operation of the engine when equipped with an afterburner or a reheat system. When afterburning engines are equipped with a C-D nozzle the throat area is variable. Nozzles for superso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
