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Lunokhod 1
''Lunokhod 1'' ( Russian: Луноход-1 ("Moonwalker 1"), also known as Аппарат 8ЕЛ № 203 ("Device 8EL No. 203")) was the first of two robotic lunar rovers landed on the Moon by the Soviet Union as part of its Lunokhod program. The ''Luna 17'' spacecraft carried ''Lunokhod 1'' to the Moon in 1970. ''Lunokhod 1'' was the first remote-controlled robot "rover" to freely move across the surface of an astronomical object beyond the Earth. It was also the first wheeled craft on another celestial body. Lunokhod 0 (No.201), the previous and first attempt to do so, launched in February 1969 but failed to reach orbit. Although only designed for a lifetime of three lunar days (approximately three Earth months), ''Lunokhod 1'' operated on the lunar surface for eleven lunar days (321 Earth days) and traversed a total distance of 10.54 km. Rover description ''Lunokhod 1'' was a lunar vehicle formed of a tub-like compartment with a large convex lid on eight independently p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Rover
A lunar rover or Moon rover is a space exploration vehicle designed to move across the surface of the Moon. The Apollo Program's Lunar Roving Vehicle was driven on the Moon by members of three American crews, Apollo 15, 16, and 17. Other rovers have been partially or fully autonomous robots, such as the Soviet Union's Lunokhods and the Chinese '' Yutus''. Three countries have had operating rovers on the Moon: the Soviet Union, the United States and China. An Indian mission failed while Japan and Greece currently have planned missions. Past missions Lunokhod 1 Lunokhod 1 (Луноход) was the first of two polycrystalline-panel-powered robotic lunar rovers landed on the Moon by the Soviet Union as part of its Lunokhod program after a previous unsuccessful attempt of a launch probe with Lunokhod 0 (No.201) in 1969. The spacecraft which carried Lunokhod 1 was named Luna 17. The spacecraft soft-landed on the Moon in the Sea of Rains on November 1970. Lunokhod was the fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Soil
Lunar soil is the fine fraction of the regolith found on the surface of the Moon. Its properties can differ significantly from those of terrestrial soil. The physical properties of lunar soil are primarily the result of mechanical disintegration of basaltic and anorthositic rock, caused by continual meteoric impacts and bombardment by solar and interstellar charged atomic particles over billions of years. The process is largely one of mechanical weathering in which the particles are ground to progressively finer size over time. This situation contrasts fundamentally to terrestrial dirt formation, mediated by the presence of molecular oxygen (O2), humidity, atmospheric wind, and a robust array of contributing biological processes. ''Lunar soil'' typically refers to only the finer fraction of lunar regolith, which is composed of grains 1 cm in diameter or less, but is often used interchangeably. Lunar dust generally connotes even finer materials than ''lunar soil''. There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Orbit
In astronomy, lunar orbit (also known as a selenocentric orbit) is the orbit of an object around the Moon. As used in the space program, this refers not to the orbit of the Moon about the Earth, but to orbits by spacecraft around the Moon. The altitude at apoapsis (point farthest from the center of attraction) for a lunar orbit is known as apolune, apocynthion, or aposelene, while the periapsis (point closest to the center of attraction) is known as perilune, pericynthion, or periselene, from names or epithets of the moon goddess. Lunar orbit insertion (LOI) is the adjustment to achieve lunar orbit, as undertaken by Apollo spacecraft for example. Low lunar orbit (LLO) are orbits below altitude. They have a period of about 2 hours. They are of particular interest in exploration of the Moon, but suffer from gravitational perturbation effects that make most unstable, and leave only a few orbital inclinations possible for indefinite ''frozen orbits'', useful for long-term sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parking Orbit
A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a parking orbit is ''direct injection'', where the rocket fires continuously (except during staging) until its fuel is exhausted, ending with the payload on the final trajectory. The technology was first used by the Soviet Venera 1 mission to Venus. Reasons for use Geostationary spacecraft Geostationary spacecraft require an orbit in the plane of the equator. Getting there requires a geostationary transfer orbit with an apogee directly above the equator. Unless the launch site itself is quite close to the equator, it requires an impractically large amount of fuel to launch a spacecraft directly into such an orbit. Instead, the craft is placed with an upper stage in an inclined parking orbit. When the craft crosses the equator, the upper stage is fired to raise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating Temperature
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating temperature). Outside this range of safe operating temperatures the device may fail. It is one component of reliability engineering. Similarly, biological systems have a viable temperature range, which might be referred to as an "operating temperature". Ranges Most devices are manufactured in several temperature grades. Broadly accepted grades are: *Commercial: 0 ° to 70 °C *Industrial: −40 ° to 85 °C *Military: −55 ° to 125 °C Nevertheless, each manufacturer defines its own temperature grades so designers must pay close attention to actual datasheet spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioisotope Heater Unit
Radioisotope heater units (RHU) are small devices that provide heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of a few grams of plutonium-238—although other radioactive isotopes could be used. The heat produced by these RHUs is given off continuously for several decades and, theoretically, for up to a century or more. In spacecraft, RHUs are used to keep other components at their operational temperatures, which may be very different to the temperature of other parts of the spacecraft. In the vacuum of space any part of the spacecraft which doesn't receive direct sunlight will cool down so much that electronics or delicate scientific instruments break down. They are simpler and more reliable than other ways of keeping components warm, such as electric heaters. Spacecraft use Most lunar and Martian surface probes use RHUs for heat, including many pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polonium-210
Polonium-210 (210Po, Po-210, historically radium F) is an isotope of polonium. It undergoes alpha decay to stable 206Pb with a half-life of 138.376 days (about months), the longest half-life of all naturally occurring polonium isotopes. First identified in 1898, and also marking the discovery of the element polonium, 210Po is generated in the decay chain of uranium-238 and radium-226. 210Po is a prominent contaminant in the environment, mostly affecting seafood and tobacco. Its extreme toxicity is attributed to intense radioactivity, capable of severely harming humans. History In 1898, Marie and Pierre Curie discovered a strongly radioactive substance in pitchblende and determined that it was a new element; it was one of the first radioactive elements discovered. Having identified it as such, they named the element polonium after Marie's home country, Poland. Willy Marckwald discovered a similar radioactive activity in 1902 and named it radio-tellurium, and at roughl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SVT2
SVT2 (SVT Två; commonly referred to as Tvåan), is one of the two main television channels broadcast by Sveriges Television in Sweden. Launched in 1969 by Sveriges Radio, the channel was until the 1990s the most watched in Sweden for many years, but now serves as SVT's specialist television network, carrying more highbrow and minority programming compared to the more mainstream SVT1. History Debate persisted throughout the 1960s over a second Swedish television channel, following the opening of ''Radiotjänst TV'' (later ''Sveriges Radio TV'') in 1956. Some wanted the new channel to be private and funded by advertising, but it was decided that the public service broadcaster, Sveriges Radio, would take responsibility. Sweden was the second Nordic country to launch a second TV channel, after Finland who did it in March 1965. ''TV2'' began broadcasting on Friday 5 December 1969 - an occasion known widely as the "channel split" (''kanalklyvningen''). While TV1 was broadcast on VH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cell
A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.Solar Cells chemistryexplained.com It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, , or resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Day
A lunar day is the period of time for Earth's Moon to complete one rotation on its axis with respect to the Sun. Due to tidal locking, it is the time the Moon takes to complete one orbit around Earth ( Earth rise to Earth set) plus about 2.2 more Earth days to return to the same Moon phase (due to the Moon's orbit around the Sun). The lunar day is roughly 29 Earth days, the length of a lunar month, and the time of which includes a full day-night cycle. Main definition Relative to the fixed stars on the celestial sphere, the Moon takes 27 Earth days, 7 hours, 43 minutes, 12 seconds to complete one orbit; however, since the Earth–Moon system advances around the Sun at the same time, the Moon must travel farther to return to the same phase. On average, this synodic period lasts 29 days, 12 hours, 44 minutes, 3 seconds, the length of a lunar month on Earth. The exact length varies over time because the speed of the Earth–Moon system around the Sun varies slightly du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances ( collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort puls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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