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Kosmos 954
Kosmos 954 (russian: Космос 954) was a reconnaissance satellite launched by the Soviet Union in 1977. A malfunction prevented safe separation of its onboard nuclear reactor; when the satellite reentered the Earth's atmosphere the following year, it scattered radioactive debris over northern Canada, some of the debris landing in the Great Slave Lake next to Fort Resolution, NWT. This prompted an extensive multiyear cleanup operation known as Operation Morning Light, which the Canadian government billed the Soviet Union for over Can$6 million, and for which the USSR eventually paid just Can$3 million in compensation. Launch and operation The satellite was part of the Soviet Union's RORSAT programme, a series of reconnaissance satellites which observed ocean traffic, including surface vessels and nuclear submarines, using active radar. It was assigned the Kosmos number 954 and was launched on 18 September 1977 at 13:55 UTC from the Baikonur Cosmodrome, on a Tsyklon-2 ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos (satellite)
Kosmos (russian: Ко́смос, , meaning " (outer) space" or " Kosmos") is a designation given to many satellites operated by the Soviet Union and subsequently Russia. Kosmos 1, the first spacecraft to be given a Kosmos designation, was launched on 16 March 1962. History The first Soviet satellites orbiting Earth were named Sputnik, Polyot (starting in 1963), Elektron (in 1964), Proton (in 1965), and Molniya (in 1965), but most have been called Kosmos since Kosmos 1 on 16 March 1962. The program has included uncrewed tests of crewed spacecraft and satellites for scientific research and military purposes. , 2548 Kosmos satellites have been launched. The spacecraft do not form a single programme, but instead consist of almost all Soviet and Russian military satellites, as well as a number of scientific satellites, and spacecraft which failed during or immediately after launch, but still reached orbit. Most Soviet and subsequently Russian military satellites were given Kosm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baker Lake (Nunavut)
Baker Lake (Inuktitut: ; 'where the river widens') is a lake in the Kivalliq Region, Nunavut, Canada. It is fed by the Thelon River from the west and the Kazan River from the south. It outflows into Chesterfield Inlet. The lake is approximately in size. It has several named bays, and a few islands. In 1762 William Christopher reached Baker Lake via Chesterfield Inlet. The Inuit hamlet of Baker Lake, Nunavut, Baker Lake is at the west end of the lake near the mouth of the Thelon River. Although the Inuit had been in the area for some time, the first outside presence was the Royal North-West Mounted Police post at the east end of the lake in 1915. This was followed in 1916 by the Hudson's Bay Company post set up at the Kazan River delta until 1930 when it moved to its present location. Fauna The lake's area is home to Beverly and Qamanirjuaq Caribou herds, as well as other wildlife associated with northern Canada's Arctic. See also *List of lakes of Nunavut *List of lakes of Cana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Slave Lake
Great Slave Lake (french: Grand lac des Esclaves), known traditionally as Tıdeè in Tłı̨chǫ Yatıì (Dogrib), Tinde’e in Wıìlıìdeh Yatii / Tetsǫ́t’ıné Yatıé (Dogrib / Chipewyan), Tu Nedhé in Dëne Sųłıné Yatıé (Chipewyan), and Tucho in Dehcho Dene Zhatıé (Slavey), is the second-largest lake in the Northwest Territories of Canada (after Great Bear Lake), the deepest lake in North America at , and the tenth-largest lake in the world by area. It is long and wide. It covers an area of in the southern part of the territory. Its given volume ranges from to and up to making it the 10th or 12th largest by volume. The lake shares its name with the First Nations peoples of the Dene family called Slavey by their enemies the Cree. Towns situated on the lake include (clockwise from east) Łutselk'e, Fort Resolution, Hay River, Hay River Reserve, Behchokǫ̀, Yellowknife, Ndilǫ, and Dettah. The only community in the East Arm is Łutselk'e, a hamlet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graveyard Orbit
A graveyard orbit, also called a junk orbit or disposal orbit, is an orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellites are moved into such orbits at the end of their operational life to reduce the probability of colliding with operational spacecraft and generating space debris. Overview A graveyard orbit is used when the change in velocity required to perform a de-orbit maneuver is too large. De-orbiting a geostationary satellite requires a delta-v of about , whereas re-orbiting it to a graveyard orbit only requires about . For satellites in geostationary orbit and geosynchronous orbits, the graveyard orbit is a few hundred kilometers beyond the operational orbit. The transfer to a graveyard orbit beyond geostationary orbit requires the same amount of fuel as a satellite needs for about three months of stationkeeping. It also requires a reliable attitude control d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reactor Core
A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place and the heat is generated. Typically, the fuel will be low-enriched uranium contained in thousands of individual fuel pins. The core also contains structural components, the means to both moderate the neutrons and control the reaction, and the means to transfer the heat from the fuel to where it is required, outside the core. Water-moderated reactors Inside the core of a typical pressurized water reactor or boiling water reactor are fuel rods with a diameter of a large gel-type ink pen, each about 4 m long, which are grouped by the hundreds in bundles called "fuel assemblies". Inside each fuel rod, pellets of uranium, or more commonly uranium oxide, are stacked end to end. Also inside the core are control rods, filled with pellets of substances like boron or hafnium or cadmium that readily capture neutrons. When the control rods are lowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Catalog Number
The Satellite Catalog Number (SATCAT, also known as NORAD (North American Aerospace Defense) Catalog Number, NORAD ID, USSPACECOM object number or simply catalog number, among similar variants) is a sequential nine-digit number assigned by the United States Space Command (USSPACECOM) in the order of launch or discovery to all artificial objects in the orbits of Earth and those that left Earth's orbit. The first catalogued object, catalog number 1, is the Sputnik 1 launch vehicle, with the Sputnik 1 satellite having been assigned catalog number 2. __NOTOC__ Objects that fail to orbit or orbit for a short time are not catalogued. The minimum object size in the catalog is in diameter. , the catalog listed 54,200 objects, including 14,102 satellites that had been launched into orbit since 1957 of which 7,043 were still active. 24,146 of the objects were well tracked while 1,850 were lost. In addition USSPACECOM was also tracking 20,900 analyst objects. Analyst objects are variably tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Aerospace Defense Command
North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection for Canada and the continental United States. Headquarters for NORAD and the NORAD/ United States Northern Command (USNORTHCOM) center are located at Peterson Space Force Base in El Paso County, near Colorado Springs, Colorado. The nearby Cheyenne Mountain Complex has the Alternate Command Center. The NORAD commander and deputy commander (CINCNORAD) are, respectively, a United States four-star general or equivalent and a Canadian lieutenant-general or equivalent. Organization CINCNORAD maintains the NORAD headquarters at Peterson Space Force Base near Colorado Springs, Colorado. The NORAD and USNORTHCOM Command Center at Peterson SFB serves as a central collection and coordination facility for a worldwide system of sensors desig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and understanding of the exact mechanics of orbi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium-235
Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide. Uranium-235 has a half-life of 703.8 million years. It was discovered in 1935 by Arthur Jeffrey Dempster. Its fission cross section for slow thermal neutrons is about 584.3±1 barns. For fast neutrons it is on the order of 1 barn. Most but not all neutron absorptions result in fission; a minority result in neutron capture forming uranium-236. Natural decay chain :\begin \ce \begin \ce \\ \ce \end \ce \\ \ce \begin \ce \\ \ce \end \ce \end Fission properties The fission of one atom of uranium-235 releases () inside the reactor. That corresponds to 19.54 TJ/ mol, or 83.14 TJ/kg. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermionic Converter
A thermionic converter consists of a hot electrode which thermionically emits electrons over a potential energy barrier to a cooler electrode, producing a useful electric power output. Caesium vapor is used to optimize the electrode work functions and provide an ion supply (by surface ionization or electron impact ionization in a plasma) to neutralize the electron space charge. Definition From a physical electronic viewpoint, thermionic energy conversion is the direct production of electric power from heat by thermionic electron emission. From a thermodynamic viewpoint, it is the use of electron vapor as the working fluid in a power-producing cycle. A thermionic converter consists of a hot emitter electrode from which electrons are vaporized by thermionic emission and a colder collector electrode into which they are condensed after conduction through the inter-electrode plasma. The resulting current, typically several amperes per square centimeter of emitter surface, de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoapsis
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.g., f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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