1.
Fobos-Grunt
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Fobos-Grunt or Phobos-Grunt was an attempted Russian sample return mission to Phobos, one of the moons of Mars. Fobos-Grunt also carried the Chinese Mars orbiter Yinghuo-1 and the tiny Living Interplanetary Flight Experiment funded by the Planetary Society, efforts to reactivate the craft were unsuccessful, and it fell back to Earth in an uncontrolled re-entry on 15 January 2012, over the Pacific Ocean west of Chile. The return vehicle was to have returned to Earth in August 2014, funded by the Russian Federal Space Agency and developed by Lavochkin and the Russian Space Research Institute, Fobos-Grunt was the first Russian-led interplanetary mission since the failed Mars 96. The last successful interplanetary missions were the Soviet Vega 2 in 1985–1986, Fobos-Grunt was designed to become the first spacecraft to return a macroscopic sample from an extraterrestrial body since Luna 24 in 1976. The cost of the project was 1.5 billion rubles, project funding for the timeframe 2009–2012, including post-launch operations, was about 2.4 billion rubles. The total cost of the mission was to have been 5 billion rubles, Zakharov had described the Phobos sample return project as possibly the most difficult interplanetary one to date. The initial spacecraft design was to be similar to the probes of the Fobos program launched in the late 1980s, development of the spacecraft started in 2001 and the preliminary design was completed in 2004. For years, the project stalled as a result of low levels of financing of the Russian space program and this changed in the summer of 2005, when the new government plan for space activities in 2006–2015 was published. Fobos-Grunt was now one of the programs flagship missions. With substantially improved funding, the date was set for October 2009. The 2004 design was revised a couple of times and international partners were invited to join the project, in June 2006, NPO Lavochkin announced that it had begun manufacturing and testing the development version of the spacecrafts onboard equipment. Yinghuo-1 weighed 115 kg and would have released by the main spacecraft into a Mars orbit. NPO Lavochkin was the main contractor developing its components. The Chief Designer of Fobos-Grunt was Maksim Martynov, in late 2012, after a 10–11. 5-month cruise, Yinghuo-1 would have separated and entered an 800×80,000 km equatorial orbit with a period of three days. The spacecraft was expected to remain on Martian orbit for one year, Yinghuo-1 would have focused mainly on the study of the external environment of Mars. Space center researchers expected to use photographs and data to study the field of Mars. A second Chinese payload, the Soil Offloading and Preparation System, was integrated in the lander, SOPSYS was a microgravity grinding tool developed by the Hong Kong Polytechnic University. The experiment would have tested one aspect of transpermia, the hypothesis that life could survive space travel, the Bulgarian Academy of Sciences contributed with a radiation measurement experiment on Fobos-Grunt
2.
Robotic spacecraft
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A robotic spacecraft is an uncrewed spacecraft, usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost, in addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spaceflight technology, many artificial satellites are robotic spacecraft, as are many landers and rovers. The first robotic spacecraft was launched by the Soviet Union on 22 July 1951, four other such flights were made through the fall of 1951. The first artificial satellite, Sputnik 1, was put into a 215-by-939-kilometer Earth orbit by the USSR) on 4 October 1957, on 3 November 1957, the USSR orbited Sputnik 2. Weighing 113 kilograms, Sputnik 2 carried the first living animal into orbit, since the satellite was not designed to detach from its launch vehicles upper stage, the total mass in orbit was 508.3 kilograms. In a close race with the Soviets, the United States launched its first artificial satellite, Explorer 1, into a 193-by-1, 373-nautical-mile orbit on 31 January 1958. Explorer I was a 80. 75-inch long by 6. 00-inch diameter cyllynder weighing 30.8 pounds, compared to Sputnik 1, a 58-centimeter sphere which weighed 83.6 kilograms. Explorer 1 carried sensors which confirmed the existence of the Van Allen belts, on 17 March 1958, the US orbited its second satellite, Vanguard 1, which was about the size of a grapefruit, and remains in a 360-by-2, 080-nautical-mile orbit as of 2016. Nine other countries have successfully launched satellites using their own vehicles, France, Australia, Japan and China, the United Kingdom, India, Israel, Iran. In spacecraft design, the United States Air Force considers a vehicle to consist of the mission payload, the bus provides physical structure, thermal control, electrical power, attitude control and telemetry, tracking and commanding. JPL divides the system of a spacecraft into subsystems. These include, This is the backbone structure. It, provides overall mechanical integrity of the spacecraft ensures spacecraft components are supported and can withstand launch loads This is sometimes referred to as the command, components in the telecommunications subsystem include radio antennas, transmitters and receivers. These may be used to communicate with stations on Earth. The supply of power on spacecraft generally come from photovoltaic cells or from a radioisotope thermoelectric generator. Other components of the subsystem include batteries for storing power and distribution circuitry that connects components to the power sources, spacecraft are often protected from temperature fluctuations with insulation
3.
Spacecraft
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A spacecraft is a vehicle, or machine designed to fly in outer space. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, space colonization, planetary exploration, on a sub-orbital spaceflight, a spacecraft enters space and then returns to the surface, without having gone into an orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies, robotic spacecraft used to support scientific research are space probes. Robotic spacecraft that remain in orbit around a body are artificial satellites. Only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2, orbital spacecraft may be recoverable or not. By method of reentry to Earth they may be divided in non-winged space capsules, Sputnik 1 was the first artificial satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957, the launch ushered in new political, military, technological, and scientific developments, while the Sputnik launch was a single event, it marked the start of the Space Age. Apart from its value as a technological first, Sputnik 1 also helped to identify the upper atmospheric layers density and it also provided data on radio-signal distribution in the ionosphere. Pressurized nitrogen in the satellites false body provided the first opportunity for meteoroid detection, Sputnik 1 was launched during the International Geophysical Year from Site No. 1/5, at the 5th Tyuratam range, in Kazakh SSR. The satellite travelled at 29,000 kilometers per hour, taking 96.2 minutes to complete an orbit and this altitude is called the Kármán line. In particular, in the 1940s there were several test launches of the V-2 rocket, as of 2016, only three nations have flown manned spacecraft, USSR/Russia, USA, and China. The first manned spacecraft was Vostok 1, which carried Soviet cosmonaut Yuri Gagarin into space in 1961, there were five other manned missions which used a Vostok spacecraft. The second manned spacecraft was named Freedom 7, and it performed a sub-orbital spaceflight in 1961 carrying American astronaut Alan Shepard to an altitude of just over 187 kilometers, there were five other manned missions using Mercury spacecraft. Other Soviet manned spacecraft include the Voskhod, Soyuz, flown unmanned as Zond/L1, L3, TKS, China developed, but did not fly Shuguang, and is currently using Shenzhou. Except for the shuttle, all of the recoverable manned orbital spacecraft were space capsules. Manned space capsules The International Space Station, manned since November 2000, is a joint venture between Russia, the United States, Canada and several other countries, some reusable vehicles have been designed only for manned spaceflight, and these are often called spaceplanes. The first example of such was the North American X-15 spaceplane, the first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19,1963. The first partially reusable spacecraft, a winged non-capsule, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarins flight
4.
Soviet Union
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The Soviet Union, officially the Union of Soviet Socialist Republics was a socialist state in Eurasia that existed from 1922 to 1991. It was nominally a union of national republics, but its government. The Soviet Union had its roots in the October Revolution of 1917 and this established the Russian Socialist Federative Soviet Republic and started the Russian Civil War between the revolutionary Reds and the counter-revolutionary Whites. In 1922, the communists were victorious, forming the Soviet Union with the unification of the Russian, Transcaucasian, Ukrainian, following Lenins death in 1924, a collective leadership and a brief power struggle, Joseph Stalin came to power in the mid-1920s. Stalin suppressed all opposition to his rule, committed the state ideology to Marxism–Leninism. As a result, the country underwent a period of rapid industrialization and collectivization which laid the foundation for its victory in World War II and postwar dominance of Eastern Europe. Shortly before World War II, Stalin signed the Molotov–Ribbentrop Pact agreeing to non-aggression with Nazi Germany, in June 1941, the Germans invaded the Soviet Union, opening the largest and bloodiest theater of war in history. Soviet war casualties accounted for the highest proportion of the conflict in the effort of acquiring the upper hand over Axis forces at battles such as Stalingrad. Soviet forces eventually captured Berlin in 1945, the territory overtaken by the Red Army became satellite states of the Eastern Bloc. The Cold War emerged by 1947 as the Soviet bloc confronted the Western states that united in the North Atlantic Treaty Organization in 1949. Following Stalins death in 1953, a period of political and economic liberalization, known as de-Stalinization and Khrushchevs Thaw, the country developed rapidly, as millions of peasants were moved into industrialized cities. The USSR took a lead in the Space Race with Sputnik 1, the first ever satellite, and Vostok 1. In the 1970s, there was a brief détente of relations with the United States, the war drained economic resources and was matched by an escalation of American military aid to Mujahideen fighters. In the mid-1980s, the last Soviet leader, Mikhail Gorbachev, sought to reform and liberalize the economy through his policies of glasnost. The goal was to preserve the Communist Party while reversing the economic stagnation, the Cold War ended during his tenure, and in 1989 Soviet satellite countries in Eastern Europe overthrew their respective communist regimes. This led to the rise of strong nationalist and separatist movements inside the USSR as well, in August 1991, a coup détat was attempted by Communist Party hardliners. It failed, with Russian President Boris Yeltsin playing a role in facing down the coup. On 25 December 1991, Gorbachev resigned and the twelve constituent republics emerged from the dissolution of the Soviet Union as independent post-Soviet states
5.
Mars
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Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is referred to as the Red Planet because the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet, Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan, there are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers, liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is about 6⁄1000 that of the Earths, except at the lowest elevations for short periods. The two polar ice caps appear to be largely of water. The volume of ice in the south polar ice cap, if melted. On November 22,2016, NASA reported finding a large amount of ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior, Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, Venus, the Moon, optical ground-based telescopes are typically limited to resolving features about 300 kilometers across when Earth and Mars are closest because of Earths atmosphere. Mars is approximately half the diameter of Earth with an area only slightly less than the total area of Earths dry land. Mars is less dense than Earth, having about 15% of Earths volume and 11% of Earths mass, the red-orange appearance of the Martian surface is caused by iron oxide, or rust. It can look like butterscotch, other common colors include golden, brown, tan. Like Earth, Mars has differentiated into a metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ±65 kilometers, consisting primarily of iron and this iron sulfide core is thought to be twice as rich in lighter elements than Earths. The core is surrounded by a mantle that formed many of the tectonic and volcanic features on the planet
6.
Natural satellite
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A natural satellite or moon is, in the most common usage, an astronomical body that orbits a planet or minor planet. In the Solar System there are six planetary satellite systems containing 178 known natural satellites, four IAU-listed dwarf planets are also known to have natural satellites, Pluto, Haumea, Makemake, and Eris. As of January 2012, over 200 minor-planet moons have been discovered, the Earth–Moon system is unique in that the ratio of the mass of the Moon to the mass of Earth is much greater than that of any other natural-satellite–planet ratio in the Solar System. At 3,474 km across, Earths Moon is 0.27 times the diameter of Earth, the first known natural satellite was the Moon, but it was considered a planet until Copernicus introduction of heliocentrism in 1543. Until the discovery of the Galilean satellites in 1610, however, galileo chose to refer to his discoveries as Planetæ, but later discoverers chose other terms to distinguish them from the objects they orbited. The first to use of the satellite to describe orbiting bodies was the German astronomer Johannes Kepler in his pamphlet Narratio de Observatis a se quatuor Iouis satellitibus erronibus in 1610. He derived the term from the Latin word satelles, meaning guard, attendant, or companion, the term satellite thus became the normal one for referring to an object orbiting a planet, as it avoided the ambiguity of moon. In 1957, however, the launching of the artificial object Sputnik created a need for new terminology, to further avoid ambiguity, the convention is to capitalize the word Moon when referring to Earths natural satellite, but not when referring to other natural satellites. A few recent authors define moon as a satellite of a planet or minor planet, there is no established lower limit on what is considered a moon. Small asteroid moons, such as Dactyl, have also been called moonlets, the upper limit is also vague. Two orbiting bodies are described as a double body rather than primary. Asteroids such as 90 Antiope are considered double asteroids, but they have not forced a clear definition of what constitutes a moon, some authors consider the Pluto–Charon system to be a double planet. In contrast, irregular satellites are thought to be captured asteroids possibly further fragmented by collisions, most of the major natural satellites of the Solar System have regular orbits, while most of the small natural satellites have irregular orbits. The Moon and possibly Charon are exceptions among large bodies in that they are thought to have originated by the collision of two large proto-planetary objects. The material that would have placed in orbit around the central body is predicted to have reaccreted to form one or more orbiting natural satellites. As opposed to planetary-sized bodies, asteroid moons are thought to form by this process. Triton is another exception, although large and in a close, circular orbit, its motion is retrograde, most regular moons in the Solar System are tidally locked to their respective primaries, meaning that the same side of the natural satellite always faces its planet. The only known exception is Saturns natural satellite Hyperion, which rotates chaotically because of the influence of Titan
7.
Deimos (moon)
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Deimos is the smaller and outer of the two natural satellites of the planet Mars, the other being Phobos. Deimos has a radius of 6.2 km and takes 30.3 hours to orbit Mars. The name Deimos is pronounced /ˈdaɪmɒs/ DY-mos, /deɪmɒs/, or sometimes /ˈdiːməs/ DEE-məs or like the Greek Δεῖμος, in Greek mythology, Deimos was the twin brother of Phobos and personified terror. Deimos is 23,460 km from Mars, much further than Marss other moon, Deimos was discovered by Asaph Hall, Sr. at the United States Naval Observatory in Washington, D. C on 12 August 1877, at about 07,48 UTC. Hall also discovered Phobos on 18 August 1877, at about 09,14 GMT and it is named after Deimos, a figure representing dread in Greek Mythology. The names, at first spelled Phobus and Deimus, were suggested by Henry Madan, Science Master of Eton, from Book XV of the Iliad, where Ares summons Dread and Fear. Deimos, like Marss other moon, Phobos, has spectra, albedos, like most bodies of its size, Deimos is highly non-spherical with triaxial dimensions of 15 ×12.2 ×11 km, making it 0.56 times the size of Phobos. Deimos is composed of rich in carbonaceous material, much like C-type asteroids. It is cratered, but the surface is smoother than that of Phobos. The regolith is highly porous and has a density of only 1.471 g/cm3. It has a velocity of 5.6 m/s and an apparent magnitude of 12.45. Only two geological features on Deimos have been given names, the craters Swift and Voltaire are named after writers who speculated on the existence of two Martian moons before Phobos and Deimos were discovered. DEIMOS Deimoss orbit is circular and is close to Marss equatorial plane. Deimos is possibly an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this hypothesis is still controversial and disputed. At its brightest it would be about as bright as Venus is from Earth, with a small telescope, a Martian observer could see Deimoss phases, which take 1.2648 days to run their course. Unlike Phobos, which orbits so fast that it rises in the west and sets in the east, Deimos rises in the east. Because Deimoss orbit is close to Mars and has only a very small inclination to Marss equator. Deimos regularly passes in front of the Sun as seen from Mars and it is too small to cause a total eclipse, appearing only as a small black dot moving across the Sun
8.
Planet
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The term planet is ancient, with ties to history, astrology, science, mythology, and religion. Several planets in the Solar System can be seen with the naked eye and these were regarded by many early cultures as divine, or as emissaries of deities. As scientific knowledge advanced, human perception of the planets changed, in 2006, the International Astronomical Union officially adopted a resolution defining planets within the Solar System. This definition is controversial because it excludes many objects of mass based on where or what they orbit. The planets were thought by Ptolemy to orbit Earth in deferent, at about the same time, by careful analysis of pre-telescopic observation data collected by Tycho Brahe, Johannes Kepler found the planets orbits were not circular but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by space probes has found that Earth and the planets share characteristics such as volcanism, hurricanes, tectonics. Planets are generally divided into two types, large low-density giant planets, and smaller rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System, in order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites, several thousands of planets around other stars have been discovered in the Milky Way. e. in the habitable zone. On December 20,2011, the Kepler Space Telescope team reported the discovery of the first Earth-sized extrasolar planets, Kepler-20e and Kepler-20f, orbiting a Sun-like star, Kepler-20. A2012 study, analyzing gravitational microlensing data, estimates an average of at least 1.6 bound planets for every star in the Milky Way, around one in five Sun-like stars is thought to have an Earth-sized planet in its habitable zone. The idea of planets has evolved over its history, from the lights of antiquity to the earthly objects of the scientific age. The concept has expanded to include not only in the Solar System. The ambiguities inherent in defining planets have led to much scientific controversy, the five classical planets, being visible to the naked eye, have been known since ancient times and have had a significant impact on mythology, religious cosmology, and ancient astronomy. In ancient times, astronomers noted how certain lights moved across the sky, as opposed to the fixed stars, ancient Greeks called these lights πλάνητες ἀστέρες or simply πλανῆται, from which todays word planet was derived. In ancient Greece, China, Babylon, and indeed all pre-modern civilizations, it was almost universally believed that Earth was the center of the Universe and that all the planets circled Earth. The first civilization known to have a theory of the planets were the Babylonians
9.
Vega 1
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Vega 1 is a Soviet space probe part of the Vega program. The spacecraft was a development of the earlier Venera craft and they were designed by Babakin Space Centre and constructed as 5VK by Lavochkin at Khimki. The craft was powered by large solar panels and instruments included an antenna dish, cameras, spectrometer, infrared sounder, magnetometers. The 4,920 kg craft was launched by a Proton 8K82K rocket from Baikonur Cosmodrome, Tyuratam, both Vega 1 and 2 were three-axis stabilized spacecraft. The spacecraft were equipped with a dual bumper shield for dust protection from Halleys comet, the descent module arrived at Venus on 11 June 1985, two days after being released from the Vega 1 flyby probe. The module, a 1500 kg,240 cm diameter sphere, contained a surface lander, the flyby probe performed a gravitational assist maneuver using Venus, and continued its mission to intercept the comet. The surface lander was identical to that of Vega 2 as well as the previous six Venera missions, the objective of the probe was the study of the atmosphere and the exposed surface of the planet. Several of these tools were developed in collaboration with French scientists. The lander successfully touched down at 7. 2°N177. 8°E /7.2,177.8 in the Mermaid Plain north of Aphrodite Terra, due to excessive turbulence, some surface experiments were inadvertently activated 20 km above the surface. Only the mass spectrometer was able to return data, the Vega 1 Lander/Balloon capsule entered the Venus atmosphere at 2,06,10 UT on 11 June 1985 at roughly 11 km/s. At approximately 2,06,25 UT the parachute attached to the landing craft cap opened at an altitude of 64 km, the cap and parachute were released 15 seconds later at 63 km altitude. The balloon package was pulled out of its compartment by parachute 40 seconds later at 61 km altitude, a second parachute opened at an altitude of 55 km,200 seconds after entry, extracting the furled balloon. The balloon was inflated 100 seconds later at 54 km and the parachute, the ballast was jettisoned when the balloon reached roughly 50 km and the balloon floated back to a stable height between 53 and 54 km some 15 to 25 minutes after entry. The mean stable height was 53.6 km, with a pressure of 535 mbar, the balloon drifted westward in the zonal wind flow with an average speed of about 69 m/s at nearly constant latitude. The probe crossed the terminator from night to day at 12,20 UT on 12 June after traversing 8500 km and it is not known how much farther the balloon travelled after the final communication. After their encounters, the Vegas motherships used the gravity of Venus, also known as a gravity assist, images started to be returned on March 4,1986, and were used to help pinpoint Giottos close flyby of the comet. The early images from Vega showed two bright areas on the comet, which were interpreted as a double nucleus. The bright areas would later turn out to be two jets emitting from the comet, the images also showed the nucleus to be dark, and the infrared spectrometer readings measured a nucleus temperature of 300 K to 400 K, much warmer than expected for an ice body
10.
Halley's Comet
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Halleys Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. Halley is the only known short-period comet that is visible to the naked eye from Earth. Halley last appeared in the parts of the Solar System in 1986. Halleys returns to the inner Solar System have been observed and recorded by astronomers since at least 240 BC, clear records of the comets appearances were made by Chinese, Babylonian, and medieval European chroniclers, but were not recognized as reappearances of the same object at the time. The comets periodicity was first determined in 1705 by English astronomer Edmond Halley, Comet Halley is commonly pronounced /ˈhæli/, rhyming with valley, or /ˈheɪli/, rhyming with daily. Spellings of Edmond Halleys name during his lifetime included Hailey, Haley, Hayley, Halley, Hawley, Halley was the first comet to be recognized as periodic. Until the Renaissance, the consensus on the nature of comets. This idea was disproved in 1577 by Tycho Brahe, who used parallax measurements to show that comets must lie beyond the Moon, many were still unconvinced that comets orbited the Sun, and assumed instead that they must follow straight paths through the Solar System. In 1687, Sir Isaac Newton published his Philosophiæ Naturalis Principia Mathematica, in which he outlined his laws of gravity and his work on comets was decidedly incomplete. Halley thus concluded that all three comets were, in fact, the same object returning every 76 years, a period that has since been amended to every 75–76 years. After a rough estimate of the perturbations the comet would sustain from the attraction of the planets. Halley died in 1742 before he could observe this himself, Halleys prediction of the comets return proved to be correct, although it was not seen until 25 December 1758, by Johann Georg Palitzsch, a German farmer and amateur astronomer. It did not pass through its perihelion until 13 March 1759 and this effect was computed prior to its return by a team of three French mathematicians, Alexis Clairaut, Joseph Lalande, and Nicole-Reine Lepaute. The confirmation of the return was the first time anything other than planets had been shown to orbit the Sun. It was also one of the earliest successful tests of Newtonian physics, the comet was first named in Halleys honour by French astronomer Nicolas Louis de Lacaille in 1759. Some scholars have proposed that first-century Mesopotamian astronomers already had recognized Halleys Comet as periodic and this theory notes a passage in the Bavli Talmud that refers to a star which appears once in seventy years that makes the captains of the ships err. It was necessary to use ancient Chinese comet observations to constrain their calculations, Halleys orbital period over the last 3 centuries has been between 75–76 years, although it has varied between 74–79 years since 240 BC. Its orbit around the Sun is highly elliptical, with an eccentricity of 0.967
11.
Kilogram
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The kilogram or kilogramme is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype of the Kilogram. The avoirdupois pound, used in both the imperial and US customary systems, is defined as exactly 0.45359237 kg, making one kilogram approximately equal to 2.2046 avoirdupois pounds. Other traditional units of weight and mass around the world are also defined in terms of the kilogram, the gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimeter of water at the melting point of ice. The final kilogram, manufactured as a prototype in 1799 and from which the IPK was derived in 1875, had an equal to the mass of 1 dm3 of water at its maximum density. The kilogram is the only SI base unit with an SI prefix as part of its name and it is also the only SI unit that is still directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Three other base units and 17 derived units in the SI system are defined relative to the kilogram, only 8 other units do not require the kilogram in their definition, temperature, time and frequency, length, and angle. At its 2011 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant, the decision was originally deferred until 2014, in 2014 it was deferred again until the next meeting. There are currently several different proposals for the redefinition, these are described in the Proposed Future Definitions section below, the International Prototype Kilogram is rarely used or handled. In the decree of 1795, the term gramme thus replaced gravet, the French spelling was adopted in the United Kingdom when the word was used for the first time in English in 1797, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with kilogram having become by far the more common, UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling. In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has used to mean both kilogram and kilometer. In 1935 this was adopted by the IEC as the Giorgi system, now known as MKS system. In 1948 the CGPM commissioned the CIPM to make recommendations for a practical system of units of measurement. This led to the launch of SI in 1960 and the subsequent publication of the SI Brochure, the kilogram is a unit of mass, a property which corresponds to the common perception of how heavy an object is. Mass is a property, that is, it is related to the tendency of an object at rest to remain at rest, or if in motion to remain in motion at a constant velocity. Accordingly, for astronauts in microgravity, no effort is required to hold objects off the cabin floor, they are weightless. However, since objects in microgravity still retain their mass and inertia, the ratio of the force of gravity on the two objects, measured by the scale, is equal to the ratio of their masses. On April 7,1795, the gram was decreed in France to be the weight of a volume of pure water equal to the cube of the hundredth part of the metre
12.
NASA Deep Space Network
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It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected Earth-orbiting missions. DSN is part of the NASA Jet Propulsion Laboratory, similar networks are run by Europe, Russia, China, India, and Japan. DSN currently consists of three deep-space communications facilities placed approximately 120 degrees apart around the Earth and they are, the Goldstone Deep Space Communications Complex outside Barstow, California. Each facility is situated in semi-mountainous, bowl-shaped terrain to shield against radio frequency interference. All DSN antennas are steerable, high-gain, parabolic reflector antennas, the antennas and data delivery systems make it possible to, acquire telemetry data from spacecraft. Perform Very Long Baseline Interferometry observations, measure variations in radio waves for radio science experiments. Monitor and control the performance of the network, the antennas at all three DSN Complexes communicate directly with the Deep Space Operations Center located at the JPL facilities in Pasadena, California. In the early years, the control center did not have a permanent facility. It was a setup with numerous desks and phones installed in a large room near the computers used to calculate orbits. In July 1961, NASA started the construction of the permanent facility, the facility was completed in October 1963 and dedicated on May 14,1964. In the initial setup of the SFOF, there were 31 consoles,100 closed-circuit television cameras, currently, the operations center personnel at SFOF monitor and direct operations, and oversee the quality of spacecraft telemetry and navigation data delivered to network users. Tracking vehicles in space is quite different from tracking missions in low Earth orbit. Deep space missions are visible for long periods of time from a portion of the Earths surface. These few stations, however, require huge antennas, ultra-sensitive receivers, Deep space is defined in several different ways. According to a 1975 NASA report, the DSN was designed to communicate with spacecraft traveling approximately 16,000 km from Earth to the farthest planets of the solar system. JPL diagrams state that at an altitude of 30,000 km and this definition means that missions to the Moon, and the Earth–Sun Lagrangian points L1 and L2, are considered near space and cannot use the ITUs deep space bands. Other Lagrangian points may or may not be subject to rule due to distance. NASA was officially established on October 1,1958, to consolidate the separately developing space-exploration programs of the US Army, US Navy, the DSN was given responsibility for its own research, development, and operation in support of all of its users
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