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Reaction Control System
A reaction control system (RCS) is a spacecraft system that uses Thrusters (spacecraft), thrusters to provide Spacecraft attitude control, attitude control and translation (physics), translation. Alternatively, reaction wheels can be used for attitude control, rather than RCS. Use of diverted engine thrust to provide stable attitude control of a V/STOL, short-or-vertical takeoff and landing aircraft below conventional winged flight speeds, such as with the Hawker Siddeley Harrier#Controls and handling, Harrier "jump jet", may also be referred to as a reaction control system. Reaction control systems are capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow control of rotation (aircraft principal axes, roll, pitch, and yaw). Reaction control systems often use combinations of large and small (vernier thruster, vernier) thrusters, to allow different levels of response. Uses Spacecr ...
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LM RCS
The abbreviation LM or lm may refer to: Places * County Leitrim, Ireland (vehicle plate code LM) * Le Mans, a place in France * Limburg-Weilburg, Germany (vehicle plate code LM) * Liptovský Mikuláš, Slovakia (vehicle plate code LM) * Lourenço Marques, Pearl of the Indian Ocean, Mozambique * Lower Mainland, a region in British Columbia, Canada * Lower Manhattan, Southern part of Manhattan, New York Arts, entertainment, and media * Little Mix, a British four-piece girl group * LM (magazine), ''LM'' (magazine), a defunct British computer game magazine * ''Living Marxism'' magazine, published under the name ''LM'' between 1997 and 2000 * Long metre or Long Measure, a hymn-metre with four lines of 8 syllables Brands and enterprises * L&M, a brand of cigarettes * Ledgewood Mall, a shopping mall in New Jersey * Legg Mason, a U.S. investment management firm; NYSE ticker symbol * Lockheed Martin, a U.S. defense contractor In transportation * ALM Antillean Airlines, a Netherlands Anti ...
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Ullage Motor
Ullage motors (also known as ullage engines or ullage rockets) are relatively small, independently fueled rocket engines that may be fired prior to main engine ignition, when the vehicle is in a zero-g situation. The resulting acceleration causes liquid in the rocket's main tanks to settle towards the aft end, ensuring uninterrupted flow to the fuel and oxidizer pumps. Description Cryogenic-liquid-fueled rockets keep their propellants in insulated tanks. These tanks are never completely filled to allow for expansion. In weightlessness, micro-gravity conditions the cryogenic liquids are without a free surface, and exist in a slushy state between solid, liquid, and gas. In this mixed state, ullage gases may be sucked into the engines, which is undesirable, as it displaces useful propellant, reduces efficiency, and may damage the engines. Small rocket engines, called "ullage motors", are sometimes used to settle the propellant before main engine ignition to allow the formation of a ...
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Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ...
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Center Of Mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point) is the unique point at any given time where the weight function, weighted relative position (vector), position of the distributed mass sums to zero. For a rigid body containing its center of mass, this is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the Phys ...
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Project Gemini
Project Gemini () was the second United States human spaceflight program to fly. Conducted after the first American crewed space program, Project Mercury, while the Apollo program was still in early development, Gemini was conceived in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966. Gemini's objective was the development of space travel techniques to support the Apollo mission to Moon landing, land astronauts on the Moon. In doing so, it allowed the United States to catch up and overcome the lead in human spaceflight capability the Soviet Union had obtained in the early years of the Space Race, by demonstrating mission endurance up to just under 14 days, longer than the eight days required for a round trip to the Moon; methods of performing extravehicular activity (EVA) without tiring; and the orbital maneuvers necessary to achieve space rendezv ...
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Space Capsule
A space capsule is a spacecraft designed to transport cargo, scientific experiments, and/or astronauts to and from space. Capsules are distinguished from other spacecraft by the ability to survive reentry and return a payload to the Earth's surface from orbit or sub-orbit, and are distinguished from other types of recoverable spacecraft by their blunt shape, not having wings and often containing little fuel other than what is necessary for a safe return. Capsule-based human spaceflight, crewed spacecraft such as Soyuz (spacecraft), Soyuz or Orion (spacecraft), Orion are often supported by a service or adapter module, and sometimes augmented with an extra module for extended space operations. Capsules make up the majority of crewed spacecraft designs, although one crewed spaceplane, the Space Shuttle, has flown in orbit. Current examples of crewed space capsules include Soyuz spacecraft, Soyuz, Shenzhou spacecraft, Shenzhou, and SpaceX Dragon 2, Dragon 2. Examples of new crew capsu ...
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Project Mercury
Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Union. Taken over from the US Air Force by the newly created civilian space agency NASA, it conducted 20 uncrewed developmental flights (some using animals), and six successful flights by astronauts. The program, which took its name from Roman mythology, cost $ (adjusted for inflation). The astronauts were collectively known as the " Mercury Seven", and each spacecraft was given a name ending with a "7" by its pilot. The Space Race began with the 1957 launch of the Soviet satellite Sputnik 1. This came as a shock to the American public, and led to the creation of NASA to expedite existing US space exploration efforts, and place most of them under civilian control. After the successful launch of the Explorer 1 satellite in 1958, crewed spac ...
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Momentum Wheel
A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through Angular momentum#Conservation of angular momentum, conservation of angular momentum. A reaction wheel can rotate only around its center of mass; it is not capable of moving from one place to another (translation (physics), translational force). Reaction wheels are used primarily by spacecraft for three-axis Spacecraft attitude control, attitude control, and do not require Rocket engine, rockets or external applicators of torque, which reduces the payload fraction, mass fraction needed for fuel. They provide a high pointing accuracy, and are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. A reaction wheel is sometimes operated at a constant (or near-constant) rotation speed, to provide a satellite with a large amount of stored angular momentum. D ...
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International Space Station
The International Space Station (ISS) is a large space station that was Assembly of the International Space Station, assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United States), Roscosmos (Russia), European Space Agency, ESA (Europe), JAXA (Japan), and Canadian Space Agency, CSA (Canada). As the largest space station ever constructed, it primarily serves as a platform for conducting scientific experiments in microgravity and studying the space environment. The station is divided into two main sections: the Russian Orbital Segment (ROS), developed by Roscosmos, and the US Orbital Segment (USOS), built by NASA, ESA, JAXA, and CSA. A striking feature of the ISS is the Integrated Truss Structure, which connect the station’s vast system of solar panels and Spacecraft thermal control, radiators to its pressurized modules. These modules support diverse functions, including scientific research, crew habitation, ...
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Hall Effect Thruster
In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. The Hall-effect thruster is classed as a moderate specific impulse (1,600s) space propulsion technology and has benefited from considerable theoretical and experimental research since the 1960s. Hall thrusters operate on a variety of propellants, the most common being xenon and krypton. Other propellants of interest include argon, bismuth, iodine, magnesium, zinc and adamantane. Hall thrusters are able to accelerate their exhaust to effective exhaust velocity, speeds between 10 and 80 km/s (1,00 ...
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Ion Thruster
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. An ion thruster creates a cloud of positive ions from a neutral gas by ionizing it to extract some electrons from its atoms. The ions are then accelerated using electricity to create thrust. Ion thrusters are categorized as either electrostatic or electromagnetic. Electrostatic thruster ions are accelerated by the Coulomb force along the electric field direction. Temporarily stored electrons are reinjected by a ''neutralizer'' in the cloud of ions after it has passed through the electrostatic grid, so the gas becomes neutral again and can freely disperse in space without any further electrical interaction with the thruster. By contrast, electromagnetic thruster ions are accelerated by the Lorentz force to accelerate all species (free electrons as well as positive and negative ions) in the same direction whatever their electric charge, and are specifically refer ...
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