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Reaction 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 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 ( translational force). Reaction wheels are used primarily by spacecraft for three-axis attitude control, and do not require rockets or external applicators of torque, which reduces the 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. Doing so alters the spacecraft's rotational dynamics so that disturbance torques perpendicular to one axis of the satellite (the axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Wheel00
Reaction may refer to a process or to a response (other), response to an action, event, or exposure. Physics and chemistry *Chemical reaction *Nuclear reaction *Reaction (physics), as defined by Newton's third law *Chain reaction (other) Biology and medicine *Adverse drug reaction *Allergy, Allergic reaction *Reflex, neural reaction *Hypersensitivity, immune reaction *Intolerance (other) *Light reaction (other) Psychology *Emotional, reaction *Reactivity (psychology), Reactivity *Proactivity, opposite of reactive behaviour *Reactive attachment disorder Politics and culture *Reactionary, a political tendency *Reaction video *Commentary (other) Proper names and titles *Reaction (album), ''Reaction'' (album), a 1986 album by American R&B singer Rebbie Jackson **Reaction (song), "Reaction" (song), the title song from the Rebbie Jackson album *"Reaction", a single by Dead Letter Circus *''Reactions'', a 2018 album by The Mods (band), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beresheet
''Beresheet'' (, ''Bərēšīṯ'', "In the beginning"; Book of Genesis) was a demonstrator of a small robotic lunar lander and lunar probe operated by SpaceIL and Israel Aerospace Industries. Its aims included inspiring youth and promoting careers in science, technology, engineering, and mathematics (Science, technology, engineering, and mathematics, STEM), and landing its magnetometer, time capsule, and Retroreflector, laser retroreflector on the Moon. The lander's gyroscopes failed on 11 April 2019 causing the main engine to shut off, which resulted in the lander crashing on the Moon. Its final resting position is 32.5956°N, 19.3496°E. The lander was previously known as ''Sparrow'' and was officially renamed to ''Beresheet'' in December 2018. Its net mass was ; when fueled at launch, its mass was . It had been compared to a washing machine, as it stood at about the height of one at and was similar in width to large household appliances. It used seven ground stations for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-82
STS-82 was the 22nd flight of the Space Shuttle Space Shuttle Discovery, ''Discovery'' and the 82nd mission of the Space Shuttle program. It was NASA's second mission to service the Hubble Space Telescope, during which ''Discovery's'' crew repaired and upgraded the telescope's scientific instruments, increasing its research capabilities. ''Discovery'' launched from Kennedy Space Center, Florida, on February 11, 1997, returning to Earth on February 21, 1997, at Kennedy Space Center. Crew ''Discovery'' was crewed by a seven person team for the STS-82 mission. Spacewalks *''EVA 1'' Lee and Smith **Start: February 14, 1997 – 04:34 UTC **End: February 14, 1997 – 11:16 UTC **Duration: 6 hours, 42 minutes *''EVA 2'' Harbaugh and Tanner **Start: February 15, 1997 – 03:25 UTC **End: February 15, 1997 – 10:52 UTC **Duration: 7 hours, 27 minutes *''EVA 3'' Lee and Smith **Start: February 16, 1997 – 02:53 UTC **End: February 16, 1997 – 10:04 UTC **Duration: 7 hours, 11 minute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hubble Space Telescope
The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most versatile, renowned as a vital research tool and as a public relations boon for astronomy. The Hubble Space Telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories program, Great Observatories. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft. Hubble features a mirror, and its five main instruments observe in the ultraviolet, visible spectrum, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of atmosphere of Earth, Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ithaco
Collins Aerospace is an American technology company that is one of the world's largest suppliers of aerospace and defense products. It was formed in 2018 from the merger of Rockwell Collins and UTC Aerospace Systems. Headquartered in Charlotte, North Carolina, it is a subsidiary of RTX Corporation. History On November 26, 2018, United Technologies announced the completion of its Rockwell Collins acquisition, after which it merged its newly acquired business with UTC Aerospace Systems to form Collins Aerospace. This acquisition controversially led to multiple class action lawsuits being filed against the company alleging that the executives deliberately misled its shareholders on the nature of the acquisition. The new company reported $26 billion of combined sales in 2019 and is composed of 68,000 employees. In 2020 United Technologies merged with Raytheon Company to form Raytheon Technologies, which has since renamed itself to RTX Corporation. In July 2023, Collins agreed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling, they have a much lower coefficient of friction than if two flat surfaces were sliding against each other. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races. Common ball bearing designs include ''angular contact, axial, deep-groove,'' an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Weather
Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ionosphere, thermosphere, and exosphere. Though physically distinct, space weather is analogous to the terrestrial weather of Earth's atmosphere of Earth, atmosphere (troposphere and stratosphere). The term "space weather" was first used in the 1950s and popularized in the 1990s. Later, it prompted research into "space climate", the large-scale and long-term patterns of space weather. History For many centuries, the effects of space weather were noticed, but not understood. Displays of aurora (astronomy), auroral light have long been observed at high latitudes. Beginnings In 1724, George Graham (clockmaker), George Graham reported that the needle of a magnetic compass was regularly deflected from magnetic north over the course of each day. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequency, frequencies of 750–420 terahertz (unit), terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively ''optical radiation''. In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity (physics), intensity, propagation direction, frequency or wavelength spectrum, and polarization (waves), polarization. Its speed of light, speed in vacuum, , is one of the fundamental physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Momentum
In Newtonian mechanics, momentum (: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass and is its velocity (also a vector quantity), then the object's momentum (from Latin '' pellere'' "push, drive") is: \mathbf = m \mathbf. In the International System of Units (SI), the unit of measurement of momentum is the kilogram metre per second (kg⋅m/s), which is dimensionally equivalent to the newton-second. Newton's second law of motion states that the rate of change of a body's momentum is equal to the net force acting on it. Momentum depends on the frame of reference, but in any inertial frame of reference, it is a ''conserved'' quantity, meaning that if a closed system is not affected by external forces, its total momentum does not change. Momentum is also conserved in special relativity (with a mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Sail
Solar sails (also known as lightsails, light sails, and photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large surfaces. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The two spacecraft to successfully use the technology for propulsion were IKAROS, launched in 2010, and LightSail-2, launched in 2019. A useful analogy to solar sailing may be a sailing boat; the light exerting a force on the large surface 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 high speeds (relative to chemical rockets) and long operating lifetimes. Since they have few moving parts and use no propellant, they can potentially be used numerous times for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LightSail
LightSail is a project to demonstrate controlled solar sailing within low Earth orbit using a CubeSat. The project was developed by The Planetary Society, a global non-profit organization devoted to space exploration. It consists of two spacecraft — LightSail 1 and LightSail 2. LightSail 1 was an engineering demonstration mission designed to test its new sail deployment method in space, it did not perform solar sailing. LightSail 2 was a fully functional spacecraft intended to demonstrate true solar sailing and incorporated the lessons learned from LightSail 1. LightSail is a follow-on project to ''Cosmos 1'' — a solar-sail spacecraft designed by The Planetary Society in the early 2000s, which was destroyed during a launch failure in 2005. Both LightSail spacecraft measured (3U CubeSat) in their stowed configuration. After sail deployment, the total area of each spacecraft was . History In 2005, The Planetary Society attempted to send a solar sail satellite named ''Cosmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Webb Space Telescope
The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, List of the most distant astronomical objects, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as observation of the Population III star, first stars and the Galaxy formation and evolution, formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets. Although the Webb's mirror diameter is 2.7 times larger than that of the Hubble Space Telescope, it produces images of comparable optical resolution, resolution because it observes in the longer-wavelength infrared spectrum. The longer the wavelength of the spectrum, the larger the information-gathering surface required (mirrors in the infrared spectrum or antenna a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
