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G-jitter
G-jitter references forms of periodic or quasisteady residual acceleration encountered in a spacecraft floating through the micro-gravity confines of space. Such variations slightly change the orientation and magnitude of a body force in a low-gravity testing environment,Nelson, Emily S. "An examination of anticipated g-jitter on space station and its effects on materials processes." (1994). https://ntrs.nasa.gov/search.jsp?R=19950006290 which can either marginally or gravely affect the result of precision-heavy dependent experiments conducted on board a space station. These accelerations are often the result of routine crew activity and equipment operation and the aerodynamic and aeromechanical forces on the spacecraft itself. Using current theoretical methods and previously collected experimental data, it is impossible to predict the exact behavior of a g-jitter acceleration, but with the aforementioned data, it is possible to notice and account for qualitative trends that hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro-g Environment
The term micro-g environment (also μg, often referred to by the term microgravity) is more or less synonymous with the terms ''weightlessness'' and ''zero-g'', but emphasising that g-forces are never exactly zero—just very small (on the International Space Station (ISS), for example, the small g-forces come from tidal effects, gravity from objects other than the Earth, such as astronauts, the spacecraft, and the Sun, air resistance, and astronaut movements that impart momentum to the space station). The symbol for microgravity, ''μg'', was used on the insignias of Space Shuttle flights STS-87 and STS-107, because these flights were devoted to microgravity research in low Earth orbit. The most commonly known microgravity environment can be found aboard the ISS which is located in low-earth orbit at an altitude of around 400 km, orbiting Earth approximately 15 times per day in what is considered free fall. The effects of free fall also enable the creation of short-du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Space Station Star Trails - JSC2012E052679
International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * ''International'' (The Three Degrees album), 1975 *''International'', 2018 album by L'Algérino Songs * The Internationale, the left-wing anthem * "International" (Chase & Status song), 2014 * "International", by Adventures in Stereo from ''Monomania'', 2000 * "International", by Brass Construction from ''Renegades'', 1984 * "International", by Thomas Leer from ''The Scale of Ten'', 1985 * "International", by Kevin Michael from ''International'' (Kevin Michael album), 2011 * "International", by McGuinness Flint from ''McGuinness Flint'', 1970 * "International", by Orchestral Manoeuvres in the Dark from '' Dazzle Ships'', 1983 * "International (Serious)", by Estelle from '' All of Me'', 2012 Politics * Political international, any transnational organization of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodic Function
A periodic function is a function that repeats its values at regular intervals. For example, the trigonometric functions, which repeat at intervals of 2\pi radians, are periodic functions. Periodic functions are used throughout science to describe oscillations, waves, and other phenomena that exhibit periodicity. Any function that is not periodic is called aperiodic. Definition A function is said to be periodic if, for some nonzero constant , it is the case that :f(x+P) = f(x) for all values of in the domain. A nonzero constant for which this is the case is called a period of the function. If there exists a least positive constant with this property, it is called the fundamental period (also primitive period, basic period, or prime period.) Often, "the" period of a function is used to mean its fundamental period. A function with period will repeat on intervals of length , and these intervals are sometimes also referred to as periods of the function. Geometrically, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Force
In physics, a body force is a force that acts throughout the volume of a body. Springer site - Book 'Solid mechanics'preview paragraph 'Body forces'./ref> Forces due to gravity, electric fields and magnetic fields are examples of body forces. Body forces contrast with contact forces or surface forces which are exerted to the surface of an object. Normal forces and shear forces between objects are surface forces as they are exerted to the surface of an object. All cohesive surface attraction and contact forces between objects are also considered as surface forces. Fictitious forces such as the centrifugal force, Euler force, and the Coriolis effect are other examples of body forces. Definition Qualitative A body force is simply a type of force, and so it has the same dimensions as force, L] sup>−2. However, it is often convenient to talk about a body force in terms of either the force per unit volume or the force per unit mass. If the force per unit volume is of interest, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Manufacturing
Space manufacturing is the production of tangible goods beyond Earth. Since most production capabilities are limited to low Earth orbit, the term in-orbit manufacturing is also frequently used. There are several rationales supporting in-space manufacturing: * The space environment, in particular the effects of microgravity and vacuum, enable the research of and production of goods that could otherwise not be manufactured on Earth. * The extraction and processing of raw materials from other astronomical bodies, also called In-Situ Resource Utilisation (ISRU) could enable more sustainable space exploration missions at reduced cost compared to launching all required resources from Earth. * Raw materials could be transported to low Earth orbit where they could be processed into goods that are shipped to Earth. By replacing terrestrial production on Earth, this seeks to preserve the Earth. * Raw materials of very high value, for example gold, silver, or platinum, could be transpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tidal Acceleration
Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite (e.g. the Moon) and the primary planet that it orbits (e.g. Earth). The acceleration causes a gradual recession of a satellite in a prograde orbit away from the primary, and a corresponding slowdown of the primary's rotation. The process eventually leads to tidal locking, usually of the smaller body first, and later the larger body (e.g. theoretically with Earth in 50 billion years). The Earth–Moon system is the best-studied case. The similar process of tidal deceleration occurs for satellites that have an orbital period that is shorter than the primary's rotational period, or that orbit in a retrograde direction. The naming is somewhat confusing, because the average speed of the satellite relative to the body it orbits is ''decreased'' as a result of tidal acceleration, and ''increased'' as a result of tidal deceleration. This conundrum occurs because a positive acceleration at one instan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diurnal Cycle
A diurnal cycle (or diel cycle) is any pattern that recurs every 24 hours as a result of one full rotation of the planet Earth around its axis. Earth's rotation causes surface temperature fluctuations throughout the day and night, as well as weather changes throughout the year. The diurnal cycle depends mainly on incoming solar radiation. Climate and atmosphere In climatology, the diurnal cycle is one of the most basic forms of climate patterns, including variations in diurnal temperature and rainfall. Diurnal cycles may be approximately sinusoidal or include components of a truncated sinusoid (due to the Sun's rising and setting) and thermal relaxation ( Newton cooling) at night. The diurnal cycle also has a great impact on carbon dioxide levels in the atmosphere, due to processes such as photosynthesis and cellular respiration. Biological effects Diurnal cycles of light and temperature can result in similar cycles in biological processes, such as photosynthesis i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Phenomena
Solar phenomena are natural phenomena which occur within the atmosphere of the Sun. These phenomena take many forms, including solar wind, radio wave flux, solar flares, coronal mass ejections, coronal heating and sunspots. These phenomena are believed to be generated by a helical dynamo, located near the center of the Sun's mass, which generates strong magnetic fields, as well as a chaotic dynamo, located near the surface, which generates smaller magnetic field fluctuations. The total sum of all solar fluctuations is referred to as solar variation. The collective effect of all solar variations within the Sun's gravitational field is referred to as space weather. A major weather component is the solar wind, a stream of plasma released from the Sun's upper atmosphere. It is responsible for the aurora, natural light displays in the sky in the Arctic and Antarctic. Space weather disturbances can cause solar storms on Earth, disrupting communications, as well as geomagnetic storm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euler Force
In classical mechanics, the Euler force is the fictitious tangential force that appears when a non-uniformly rotating reference frame is used for analysis of motion and there is variation in the angular velocity of the reference frame's axes. The Euler acceleration (named for Leonhard Euler), also known as azimuthal acceleration or transverse acceleration is that part of the absolute acceleration that is caused by the variation in the angular velocity of the reference frame. Intuitive example The Euler force will be felt by a person riding a merry-go-round. As the ride starts, the Euler force will be the apparent force pushing the person to the back of the horse; and as the ride comes to a stop, it will be the apparent force pushing the person towards the front of the horse. A person on a horse close to the perimeter of the merry-go-round will perceive a greater apparent force than a person on a horse closer to the axis of rotation. Mathematical description The direction and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine Wave
A sine wave, sinusoidal wave, or just sinusoid is a curve, mathematical curve defined in terms of the ''sine'' trigonometric function, of which it is the graph of a function, graph. It is a type of continuous wave and also a Smoothness, smooth periodic function. It occurs often in mathematics, as well as in physics, engineering, signal processing and many other fields. Formulation Its most basic form as a function of time (''t'') is: y(t) = A\sin(2 \pi f t + \varphi) = A\sin(\omega t + \varphi) where: * ''A'', ''amplitude'', the peak deviation of the function from zero. * ''f'', ''frequency, ordinary frequency'', the ''Real number, number'' of oscillations (cycles) that occur each second of time. * ''ω'' = 2''f'', ''angular frequency'', the rate of change of the function argument in units of radians per second. * \varphi, ''phase (waves), phase'', specifies (in radians) where in its cycle the oscillation is at ''t'' = 0. When \varphi is non-zero, the entire waveform appears to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum—or random, such as the movement of a tire on a gravel road. Vibration can be desirable: for example, the motion of a tuning fork, the Reed (music), reed in a woodwind instrument or harmonica, a mobile phone, or the cone of a loudspeaker. In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For example, the vibrational motions of engines, electric motors, or any Machine, mechanical device in operation are typically unwanted. Such vibrations could be caused by Engine balance, imbalances in the rotating parts, uneven friction, or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations. The studies of sound and vibration are closely related. Sound, or pressure waves, are ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Orbiter
The Space Shuttle orbiter is the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the discontinued Space Shuttle program. Operated from 1977 to 2011 by NASA, the U.S. space agency, this vehicle could carry astronauts and payloads into low Earth orbit, perform in-space operations, then re-enter the atmosphere and land as a glider, returning its crew and any on-board payload to the Earth. Six orbiters were built for flight: ''Enterprise'', '' Columbia'', '' Challenger'', ''Discovery'', ''Atlantis'', and '' Endeavour''. All were built in Palmdale, California, by the Pittsburgh, Pennsylvania-based Rockwell International company. The first orbiter, ''Enterprise'', made its maiden flight in 1977. An unpowered glider, it was carried by a modified Boeing 747 airliner called the Shuttle Carrier Aircraft and released for a series of atmospheric test flights and landings. ''Enterprise'' was partially disassembled and retired aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
