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Ballistic Missiles
A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are guided only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles stay within the Earth's atmosphere, while intercontinental ballistic missiles (ICBMs) are launched on a sub-orbital flight. These weapons are in a distinct category from cruise missiles, which are aerodynamically guided in powered flight. Unlike cruise missiles, which are restricted to the atmosphere, it is advantageous for ballistic missiles to avoid the denser parts of the atmosphere and they may travel above the atmosphere into outer space. History The earliest form of ballistic missile dates from the 13th century with its use derived from the history of rockets. In the 14th century, the Ming Chinese navy used an early form of a ballistic missile weapon called the Huolongchushui in naval battles against enemy ships.Needham, Volume 5, Part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minuteman III MIRV Path
Minutemen were members of the organized New England colonial militia companies trained in weaponry, tactics, and military strategies during the American Revolutionary War. They were known for being ready at a minute's notice, hence the name. Minutemen provided a highly mobile, rapidly deployed force that enabled the colonies to respond immediately to military threats. They were an evolution from the prior colonial rapid-response units. The minutemen were among the first to fight in the American Revolution. Their teams constituted about a quarter of the entire militia. They were generally younger, more mobile, and provided with weapons and arms by the local governments. They were still part of the overall militia regimental organizations in the New England Colonies. The term has also been applied to various later United States civilian paramilitary forces. History In the colony of Massachusetts Bay Colony, Massachusetts Bay, all able-bodied men between the ages of 16 and 60 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenwood Publishing Group
Greenwood Publishing Group, Inc. (GPG), also known as ABC-Clio/Greenwood (stylized ABC-CLIO/Greenwood), is an educational and academic publisher ( middle school through university level) which is today part of ABC-Clio. Established in 1967 as Greenwood Press, Inc. and based in Westport, Connecticut, GPG publishes reference works under its Greenwood Press imprint, and scholarly, professional, and general interest books under its related imprint, Praeger Publishers (). Also part of GPG is Libraries Unlimited, which publishes professional works for librarians and teachers. History 1967–1999 The company was founded as Greenwood Press, Inc. in 1967 by Harold Mason, a librarian and antiquarian bookseller, and Harold Schwartz who had a background in trade publishing. Based in Greenwood, New York, the company initially focused on reprinting out-of-print works, particularly titles listed in the American Library Association's first edition of ''Books for College Libraries'' (1967), un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apogee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elliptic orbit. The name for each apsis is created from the prefixes ''ap-'', ''apo-'' (), or ''peri-'' (), each referring to the farthest and closest point to the primary body the affixing necessary suffix that describes the primary body in the orbit. In this case, the suffix for Earth is ''-gee'', so the apsides' names are ''apogee'' and ''perigee''. For the Sun, its suffix is ''-helion'', so the names are ''aphelion'' and ''perihelion''. According to Newton's laws of motion, all periodic orbits are ellipses. The barycenter of the two bodies may lie well within the bigger body—e.g., the Earth–Moon barycenter is about 75% of the way from Earth's center to its surface. If, compared to the larger mass, the smaller mass is negligible (e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-orbital Spaceflight
A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the atmosphere or surface of the gravitating body from which it was launched, so that it will not complete one orbital revolution (it does not become an artificial satellite) or reach escape velocity. For example, the path of an object launched from Earth that reaches the Kármán line (at ) above sea level), and then falls back to Earth, is considered a sub-orbital spaceflight. Some sub-orbital flights have been undertaken to test spacecraft and launch vehicles later intended for orbital spaceflight. Other vehicles are specifically designed only for sub-orbital flight; examples include crewed vehicles, such as the X-15 and SpaceShipOne, and uncrewed ones, such as ICBMs and sounding rockets. Flights which attain sufficient velocity to go into low Earth orbit, and then de-orbit before completing their first full orbit, are not considered sub-orbital. Exa ... [...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 fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket
A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere. Multistage rockets are capable of attaining escape velocity from Earth and therefore can achieve unlimited maximum altitude. Compared with airbreathing engines, rockets are lightweight and powerful and capable of generating large accelerations. To control their flight, rockets rely on momentum, airfoils, auxiliary reaction engines, gimballed thrust, momentum wheels, deflection of the exhaust stream, propellant flow, spin, or gravity. Rockets for military and recreational uses date back to at least 13th-century Chin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as ''boats'' rather than ''ships'' irrespective of their size. Although experimental submarines had been built earlier, submarine design took off during the 19th century, and they were adopted by several navies. They were first widely used during World War I (1914–1918), and are now used in many navies, large and small. Military uses include attacking enemy surface ships (merchant and military) or other submarines, and for aircraft carrier protection, blockade running, nuclear deterrence, reconnaissance, conventional land attack (for example, using a cruise missile), and covert insertion o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navy
A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields. The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, deter or confront piracy, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of the navy also may incorporate nuclear deterrence by use of submarine-launched ballistic missiles. Naval operations can be broadly divided between riverine and littoral applications ( brown-water navy), open-ocean applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in a few cases the Powered lift, downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), Glider (aircraft), gliders, Powered paragliding, 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.'' Aircrew, Crewed aircraft are flown by an onboard Aircraft pilot, 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, Powered aircraft#Methods of propulsion, aircraft propulsion, usage and others. History Flying model craft an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transporter Erector Launcher
A transporter erector launcher (TEL) is a missile vehicle with an integrated tractor unit that can carry, elevate to firing position and launch one or more missiles. History Such vehicles exist for both surface-to-air missiles and surface-to-surface missiles. Early on, such missiles were launched from fixed sites and had to be loaded onto trucks for transport, making them more vulnerable to attack, since once they were spotted by the enemy they could not easily be relocated, and if they were it often took hours or even days to prepare them for launch once they reached their new site. Usually a number of TELs and TELARs are linked to one command post vehicle (CP or CPV). They may use target information from target acquisition, designation and guidance radar (TADAGR or TAR). Transporter erector launcher and radar A transporter erector launcher and radar (TELAR) is a type of TEL that also incorporates part or all of the radar system necessary for firing the surface-to-air mis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Reentry
Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entry of astronomical objects, space debris, or bolides; and ''controlled entry'' (or ''reentry'') of a spacecraft capable of being navigated or following a predetermined course. Technologies and procedures allowing the controlled atmospheric ''entry, descent, and landing'' of spacecraft are collectively termed as ''EDL''. Objects entering an atmosphere experience atmospheric drag, which puts mechanical stress on the object, and aerodynamic heating—caused mostly by compression of the air in front of the object, but also by drag. These forces can cause loss of mass (ablation) or even complete disintegration of smaller objects, and objects with lower compressive strength can explode. Crewed space vehicles must be slowed to subsonic spee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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