87-647: The Chinese Lunar Exploration Program ( CLEP ; Chinese : 中国探月工程 ; pinyin : Zhōngguó Tànyuè Gōngchéng ), also known as the Chang'e Project (Chinese: 嫦娥工程 ; pinyin: Cháng'é Gōngchéng ) after the Chinese Moon goddess Chang'e , is an ongoing series of robotic Moon missions by the China National Space Administration (CNSA). The program encompasses lunar orbiters , landers , rovers and sample return spacecraft , launched using
174-424: A computer vision system in which the data from a down-facing camera, as well as 2 ranging devices, were processed using specialized software. The software controlled the final stages of descent, adjusting the attitude of the spacecraft and the throttle of its main engine. The spacecraft hovered first at 100 meters (330 feet), then at 30 meters (98 feet), as it searched for a suitable spot to set down. The Yutu rover
261-488: A 3,000-kilometer (1,900-mile) VLBI antenna. A proprietary ground application system is responsible for downlink data reception. In 2019, China National Space Administration head Zhang Kejian announced that China is planning to build a scientific research station on the Moon's south pole "within the next 10 years". Ouyang Ziyuan , a geologist and chemical cosmologist , is the program's chief scientist. Ye Peijian serves as
348-408: A Greek root) were used by physicist and science-fiction author Geoffrey A. Landis in a story published in 1998, thus appearing before perinigricon and aponigricon (from Latin) in the scientific literature in 2002. The suffixes shown below may be added to prefixes peri- or apo- to form unique names of apsides for the orbiting bodies of the indicated host/ (primary) system. However, only for
435-434: A conversion table. While exercising such derivation, the following rules should be observed: Sample Derivations : The Series One List of Variant Characters reduces the number of total standard characters. First, amongst each set of variant characters sharing identical pronunciation and meaning, one character (usually the simplest in form) is elevated to the standard character set, and the rest are made obsolete. Then amongst
522-734: A deputy chief designer with the China Manned Space Agency (CMSA), publicly introduced a preliminary plan to land two astronauts on the Moon by the year 2030 using the Mengzhou crewed spacecraft and the Lanyue crewed lunar lander. On 28 September 2024, in Chongqing , the China Manned Space Agency (CMSA) unveiled the extravehicular lunar spacesuit and also solicited suggestions for a name for
609-487: A different epoch will generate differences. The time-of-perihelion-passage as one of six osculating elements is not an exact prediction (other than for a generic two-body model ) of the actual minimum distance to the Sun using the full dynamical model . Precise predictions of perihelion passage require numerical integration . The two images below show the orbits, orbital nodes , and positions of perihelion (q) and aphelion (Q) for
696-586: A laser altimeter provided by the German Aerospace Center (DLR), which mapped the lunar topography with high precision. It also used ESA’s deep space network for communication and navigation during its extended mission to the asteroid 4179 Toutatis. Chang’e 3: The first Chinese lunar lander and rover, launched in 2013. It carried a lunar ultraviolet telescope (LUT) developed by the National Astronomical Observatories of China (NAOC) and
783-599: A newly coined phono-semantic compound : Removing radicals Only retaining single radicals Replacing with ancient forms or variants : Adopting ancient vulgar variants : Readopting abandoned phonetic-loan characters : Copying and modifying another traditional character : Based on 132 characters and 14 components listed in Chart 2 of the Complete List , the 1,753 derived characters found in Chart 3 can be created by systematically simplifying components using Chart 2 as
870-464: A practice which has always been present as a part of the Chinese writing system. The official name tends to refer to the specific, systematic set published by the Chinese government, which includes not only simplifications of individual characters, but also a substantial reduction in the total number of characters through the merger of formerly distinct forms. According to Chinese palaeographer Qiu Xigui ,
957-404: A single standardized character, usually the simplest among all variants in form. Finally, many characters were left untouched by simplification and are thus identical between the traditional and simplified Chinese orthographies. The Chinese government has never officially announced the completion of the simplification process after the bulk of characters were introduced by the 1960s. In the wake of
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#17328526572041044-463: A time relative to seasons, since this determines the contribution of the elliptical orbit to seasonal variations. The variation of the seasons is primarily controlled by the annual cycle of the elevation angle of the Sun, which is a result of the tilt of the axis of the Earth measured from the plane of the ecliptic . The Earth's eccentricity and other orbital elements are not constant, but vary slowly due to
1131-435: Is 236 years early, less accurately shows Eris coming to perihelion in 2260. 4 Vesta came to perihelion on 26 December 2021, but using a two-body solution at an epoch of July 2021 less accurately shows Vesta came to perihelion on 25 December 2021. Trans-Neptunian objects discovered when 80+ AU from the Sun need dozens of observations over multiple years to well constrain their orbits because they move very slowly against
1218-448: Is a complex three-vector control process. The Chang'e satellites need to adjust their attitude very carefully to maintain an optimal angle towards all three bodies. During the second phase of the program, in which the spacecraft were required to soft-land on the lunar surface, it was necessary to devise a system of automatic hazard avoidance in order that the landers would not attempt to touch down on unsuitable terrain. Chang'e 3 utilized
1305-440: Is actually more complex than eliminated ones. An example is the character 搾 which is eliminated in favor of the variant form 榨 . The 扌 'HAND' with three strokes on the left of the eliminated 搾 is now seen as more complex, appearing as the ⽊ 'TREE' radical 木 , with four strokes, in the chosen variant 榨 . Not all characters standardised in the simplified set consist of fewer strokes. For instance,
1392-504: Is also equipped with front-facing stereo cameras and hazard avoidance technology. Chang’e 1: The first Chinese lunar orbiter, launched in 2007. It carried a European Space Agency (ESA) instrument called D-CIXS, which measured the elemental composition of the lunar surface. It also received tracking and data relay support from ESA’s ground stations in Australia and Spain. Chang’e 2: The second Chinese lunar orbiter, launched in 2010. It carried
1479-454: Is derived. Merging homophonous characters: Adapting cursive shapes ( 草書楷化 ): Replacing a component with a simple arbitrary symbol (such as 又 and 乂 ): Omitting entire components : Omitting components, then applying further alterations : Structural changes that preserve the basic shape Replacing the phonetic component of phono-semantic compounds : Replacing an uncommon phonetic component : Replacing entirely with
1566-399: Is lowest. Despite this, summers in the northern hemisphere are on average 2.3 °C (4 °F) warmer than in the southern hemisphere, because the northern hemisphere contains larger land masses, which are easier to heat than the seas. Perihelion and aphelion do however have an indirect effect on the seasons: because Earth's orbital speed is minimum at aphelion and maximum at perihelion,
1653-809: Is now discouraged. A State Language Commission official cited "oversimplification" as the reason for restoring some characters. The language authority declared an open comment period until 31 August 2009, for feedback from the public. In 2013, the List of Commonly Used Standard Chinese Characters was published as a revision of the 1988 lists; it included a total of 8105 characters. It included 45 newly recognized standard characters that were previously considered variant forms, as well as official approval of 226 characters that had been simplified by analogy and had seen wide use but were not explicitly given in previous lists or documents. Singapore underwent three successive rounds of character simplification , eventually arriving at
1740-540: Is used instead of 叠 in regions using traditional characters. The Chinese government stated that it wished to keep Chinese orthography stable. The Chart of Generally Utilized Characters of Modern Chinese was published in 1988 and included 7000 simplified and unsimplified characters. Of these, half were also included in the revised List of Commonly Used Characters in Modern Chinese , which specified 2500 common characters and 1000 less common characters. In 2009,
1827-489: The "line of nodes" where a planet's tilted orbit intersects the plane of reference; here they may be 'seen' as the points where the blue section of an orbit meets the pink. The chart shows the extreme range—from the closest approach (perihelion) to farthest point (aphelion)—of several orbiting celestial bodies of the Solar System : the planets, the known dwarf planets, including Ceres , and Halley's Comet . The length of
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#17328526572041914-473: The ⼓ ' WRAP ' radical used in the traditional character 沒 is simplified to ⼏ ' TABLE ' to form the simplified character 没 . By systematically simplifying radicals, large swaths of the character set are altered. Some simplifications were based on popular cursive forms that embody graphic or phonetic simplifications of the traditional forms. In addition, variant characters with identical pronunciation and meaning were reduced to
2001-490: The Cultural Revolution , a second round of simplified characters was promulgated in 1977—largely composed of entirely new variants intended to artificially lower the stroke count, in contrast to the first round—but was massively unpopular and never saw consistent use. The second round of simplifications was ultimately retracted officially in 1986, well after they had largely ceased to be used due to their unpopularity and
2088-658: The Long March series of rockets . A human lunar landing component may have been added to the program, after China publicly announced crewed lunar landing plans by the year 2030 during a conference in July 2023. The program's launches and flights are monitored by a telemetry, tracking, and command (TT&C) system, which uses 50-meter (160-foot) radio antennas in Beijing and 40-meter (130-foot) antennas in Kunming , Shanghai , and Ürümqi to form
2175-506: The Moon's south pole . The Phase IV program entered active development in 2023 following the successful completion of the previous three phases. In 2019, China was reviewing preliminary studies for a crewed lunar landing mission in the 2030s, and possibly building an outpost near the lunar south pole with international cooperation. On 12 July 2023, at the 9th China (International) Commercial Aerospace Forum in Wuhan , Hubei province, Zhang Hailian,
2262-542: The Qin dynasty (221–206 BC) the character meaning 'bright' was written as either 明 or 朙 —with either 日 'Sun' or 囧 'window' on the left, with the 月 'Moon' component on the right. Li Si ( d. 208 BC ), the Chancellor of Qin, attempted to universalize the Qin small seal script across China following the wars that had politically unified the country for
2349-402: The inner planets, situated outward from the Sun as Mercury, Venus, Earth, and Mars. The reference Earth-orbit is colored yellow and represents the orbital plane of reference . At the time of vernal equinox, the Earth is at the bottom of the figure. The second image (below-right) shows the outer planets, being Jupiter, Saturn, Uranus, and Neptune. The orbital nodes are the two end points of
2436-428: The precession of the axes .) The dates and times of the perihelions and aphelions for several past and future years are listed in the following table: The following table shows the distances of the planets and dwarf planets from the Sun at their perihelion and aphelion. These formulae characterize the pericenter and apocenter of an orbit: While, in accordance with Kepler's laws of planetary motion (based on
2523-520: The states of ancient China , with his chief chronicler having "[written] fifteen chapters describing" what is referred to as the " big seal script ". The traditional narrative, as also attested in the Shuowen Jiezi dictionary ( c. 100 AD ), is that the Qin small seal script that would later be imposed across China was originally derived from the Zhou big seal script with few modifications. However,
2610-472: The "Dot" stroke : The traditional components ⺥ and 爫 become ⺈ : The traditional component 奐 becomes 奂 : Apogee An apsis (from Ancient Greek ἁψίς ( hapsís ) 'arch, vault'; pl. apsides / ˈ æ p s ɪ ˌ d iː z / AP -sih-deez ) is the farthest or nearest point in the orbit of a planetary body about its primary body . The line of apsides (also called apse line, or major axis of
2697-461: The 1919 May Fourth Movement —many anti-imperialist intellectuals throughout China began to see the country's writing system as a serious impediment to its modernization. In 1916, a multi-part English-language article entitled "The Problem of the Chinese Language" co-authored by the Chinese linguist Yuen Ren Chao (1892–1982) and poet Hu Shih (1891–1962) has been identified as a turning point in
Chinese Lunar Exploration Program - Misplaced Pages Continue
2784-476: The 1986 General List of Simplified Chinese Characters , hereafter the General List . All characters simplified this way are enumerated in Chart 1 and Chart 2 in the 1986 Complete List . Characters in both charts are structurally simplified based on similar set of principles. They are separated into two charts to clearly mark those in Chart 2 as 'usable as simplified character components', based on which Chart 3
2871-508: The 1986 mainland China revisions. Unlike in mainland China, Singapore parents have the option of registering their children's names in traditional characters. Malaysia also promulgated a set of simplified characters in 1981, though completely identical to the mainland Chinese set. They are used in Chinese-language schools. All characters simplified this way are enumerated in Charts 1 and 2 of
2958-556: The Chang'e missions imposed strict requirements for environmental adaptability and reliability of the probes and their instruments. The high-radiation environment in Earth-Moon space required hardened electronics to prevent electromagnetic damage to spacecraft instruments. The extreme temperature range, from 130 degrees Celsius (266 degrees Fahrenheit) on the side of the spacecraft facing the Sun to −170 degrees Celsius (−274 degrees Fahrenheit) on
3045-470: The Chinese government published a major revision to the list which included a total of 8300 characters. No new simplifications were introduced. In addition, slight modifications to the orthography of 44 characters to fit traditional calligraphic rules were initially proposed, but were not implemented due to negative public response. Also, the practice of unrestricted simplification of rare and archaic characters by analogy using simplified radicals or components
3132-457: The Earth reaches aphelion currently in early July, approximately 14 days after the June solstice . The aphelion distance between the Earth's and Sun's centers is currently about 1.016 71 AU or 152,097,700 km (94,509,100 mi). The dates of perihelion and aphelion change over time due to precession and other orbital factors, which follow cyclical patterns known as Milankovitch cycles . In
3219-446: The Earth, Moon and Sun systems are the unique suffixes commonly used. Exoplanet studies commonly use -astron , but typically, for other host systems the generic suffix, -apsis , is used instead. The perihelion (q) and aphelion (Q) are the nearest and farthest points respectively of a body's direct orbit around the Sun . Comparing osculating elements at a specific epoch to those at
3306-399: The Earth, Moon and Sun. All onboard detectors must be kept facing the lunar surface in order to complete their scientific missions, communication antennas have to face the Earth in order to receive commands and transfer scientific data, and solar panels must be oriented toward the Sun in order to acquire power. During lunar orbit, the Earth, the Moon and the Sun also move, so attitude control
3393-527: The Earth, Sun, stars, and the Galactic Center respectively. The suffix -jove is occasionally used for Jupiter, but -saturnium has very rarely been used in the last 50 years for Saturn. The -gee form is also used as a generic closest-approach-to "any planet" term—instead of applying it only to Earth. During the Apollo program , the terms pericynthion and apocynthion were used when referring to orbiting
3480-532: The European Space Agency’s tracking station. Chang’e-5: The first mission to return lunar samples since 1976, with international cooperation in telemetry, tracking, and command from the European Space Agency, Argentina, Namibia, Pakistan, and other countries and organizations. It also carried a French magnetic field detector. Scientists from various countries, including Australia, Russia, France,
3567-801: The International Lunar Observatory Association (ILOA), which performed the first astronomical observations from the lunar surface. It also received data relay support from NASA’s Lunar Reconnaissance Orbiter (LRO) for the landing of the Chang’e 3 probe. Chang’e-4: The first mission to land and explore the far side of the Moon, with four international scientific payloads from the Netherlands, Germany, Sweden, and Saudi Arabia. It also received support from NASA’s LRO team, Russia’s radioisotope heat source, China’s deep space station in Argentina, and
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3654-545: The Moon ; they reference Cynthia, an alternative name for the Greek Moon goddess Artemis . More recently, during the Artemis program , the terms perilune and apolune have been used. Regarding black holes, the term peribothron was first used in a 1976 paper by J. Frank and M. J. Rees, who credit W. R. Stoeger for suggesting creating a term using the greek word for pit: "bothron". The terms perimelasma and apomelasma (from
3741-457: The Moon and during operations in lunar orbit. The distance across China from east to west is 5,000 kilometers (3,100 miles), forming another challenge to TT&C continuity. At present, the combination of the TT&;C system and the Chinese astronomical observation network has met the needs of the Chang'e program, but only by a small margin. The complexity of the space environment encountered during
3828-586: The People's Republic, the idea of a mass simplification of character forms first gained traction in China during the early 20th century. In 1909, the educator and linguist Lufei Kui formally proposed the use of simplified characters in education for the first time. Over the following years—marked by the 1911 Xinhai Revolution that toppled the Qing dynasty , followed by growing social and political discontent that further erupted into
3915-458: The Sun is 0.7 million km, and the radius of Jupiter (the largest planet) is 0.07 million km, both too small to resolve on this image. Currently, the Earth reaches perihelion in early January, approximately 14 days after the December solstice . At perihelion, the Earth's center is about 0.983 29 astronomical units (AU) or 147,098,070 km (91,402,500 mi) from the Sun's center. In contrast,
4002-584: The US to China and build a crewed lunar lander. Simplified Chinese characters Simplified Chinese characters are one of two standardized character sets widely used to write the Chinese language , with the other being traditional characters . Their mass standardization during the 20th century was part of an initiative by the People's Republic of China (PRC) to promote literacy, and their use in ordinary circumstances on
4089-648: The United States, the United Kingdom, and Sweden, have participated in scientific research involving Chinese lunar samples. In November 2017, China and Russia signed an agreement on cooperative lunar and deep space exploration. The agreement includes six sectors, covering lunar and deep space, joint spacecraft development, space electronics, Earth remote sensing data, and space debris monitoring. Russia may also look to develop closer ties with China in human spaceflight, and even shift its human spaceflight cooperation from
4176-425: The actual closest approach between the Sun's and the Earth's centers (which in turn defines the timing of perihelion in a given year). Because of the increased distance at aphelion, only 93.55% of the radiation from the Sun falls on a given area of Earth's surface as does at perihelion, but this does not account for the seasons , which result instead from the tilt of Earth's axis of 23.4° away from perpendicular to
4263-444: The body of epigraphic evidence comparing the character forms used by scribes gives no indication of any real consolidation in character forms prior to the founding of the Qin. The Han dynasty (202 BC – 220 AD) that inherited the Qin administration coincided with the perfection of clerical script through the process of libian . Eastward spread of Western learning Though most closely associated with
4350-447: The broadest trend in the evolution of Chinese characters over their history has been simplification, both in graphical shape ( 字形 ; zìxíng ), the "external appearances of individual graphs", and in graphical form ( 字体 ; 字體 ; zìtǐ ), "overall changes in the distinguishing features of graphic[al] shape and calligraphic style, [...] in most cases refer[ring] to rather obvious and rather substantial changes". The initiatives following
4437-407: The chosen variants, those that appear in the "Complete List of Simplified Characters" are also simplified in character structure accordingly. Some examples follow: Sample reduction of equivalent variants : Ancient variants with simple structure are preferred : Simpler vulgar forms are also chosen : The chosen variant was already simplified in Chart 1 : In some instances, the chosen variant
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#17328526572044524-595: The confusion they caused. In August 2009, China began collecting public comments for a revised list of simplified characters; the resulting List of Commonly Used Standard Chinese Characters lists 8,105 characters, including a few revised forms, and was implemented for official use by China's State Council on 5 June 2013. In Chinese, simplified characters are referred to by their official name 简化字 ; jiǎnhuàzì , or colloquially as 简体字 ; jiǎntǐzì . The latter term refers broadly to all character variants featuring simplifications of character form or structure,
4611-422: The conservation of angular momentum ) and the conservation of energy, these two quantities are constant for a given orbit: where: Note that for conversion from heights above the surface to distances between an orbit and its primary, the radius of the central body has to be added, and conversely. The arithmetic mean of the two limiting distances is the length of the semi-major axis a . The geometric mean of
4698-638: The country. In 1935, the first official list of simplified forms was published, consisting of 324 characters collated by Peking University professor Qian Xuantong . However, fierce opposition within the KMT resulted in the list being rescinded in 1936. Work throughout the 1950s resulted in the 1956 promulgation of the Chinese Character Simplification Scheme , a draft of 515 simplified characters and 54 simplified components, whose simplifications would be present in most compound characters. Over
4785-526: The distance measured between the barycenter of the 2-body system and the center of mass of the orbiting body. However, in the case of a spacecraft , the terms are commonly used to refer to the orbital altitude of the spacecraft above the surface of the central body (assuming a constant, standard reference radius). The words "pericenter" and "apocenter" are often seen, although periapsis/apoapsis are preferred in technical usage. The words perihelion and aphelion were coined by Johannes Kepler to describe
4872-447: The economic problems in China during that time. Lu Xun , one of the most prominent Chinese authors of the 20th century, stated that "if Chinese characters are not destroyed, then China will die" ( 漢字不滅，中國必亡 ). During the 1930s and 1940s, discussions regarding simplification took place within the ruling Kuomintang (KMT) party. Many members of the Chinese intelligentsia maintained that simplification would increase literacy rates throughout
4959-512: The first time. Li prescribed the 朙 form of the word for 'bright', but some scribes ignored this and continued to write the character as 明 . However, the increased usage of 朙 was followed by proliferation of a third variant: 眀 , with 目 'eye' on the left—likely derived as a contraction of 朙 . Ultimately, 明 became the character's standard form. The Book of Han (111 AD) describes an earlier attempt made by King Xuan of Zhou ( d. 782 BC ) to unify character forms across
5046-465: The following decade, the Script Reform Committee deliberated on characters in the 1956 scheme, collecting public input regarding the recognizability of variants, and often approving forms in small batches. Parallel to simplification, there were also initiatives aimed at eliminating the use of characters entirely and replacing them with pinyin as an official Chinese alphabet, but this possibility
5133-431: The form of various payloads and a robotic station is invited by China. The first phase entailed the launch of two lunar orbiters , and is now effectively complete. The second phase is ongoing, and incorporates spacecraft capable of soft-landing on the Moon and deploying lunar rovers . The third phase included a lunar sample-return mission . Phase IV is the development of an autonomous lunar research station near
5220-430: The founding of the Qin dynasty (221–206 BC) to universalize the use of their small seal script across the recently conquered parts of the empire is generally seen as being the first real attempt at script reform in Chinese history. Before the 20th century, variation in character shape on the part of scribes, which would continue with the later invention of woodblock printing , was ubiquitous. For example, prior to
5307-550: The history of the Chinese script—as it was one of the first clear calls for China to move away from the use of characters entirely. Instead, Chao proposed that the language be written with an alphabet, which he saw as more logical and efficient. The alphabetization and simplification campaigns would exist alongside one another among the Republican intelligentsia for the next several decades. Recent commentators have echoed some contemporary claims that Chinese characters were blamed for
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#17328526572045394-483: The horizontal bars correspond to the extreme range of the orbit of the indicated body around the Sun. These extreme distances (between perihelion and aphelion) are the lines of apsides of the orbits of various objects around a host body. Distances of selected bodies of the Solar System from the Sun. The left and right edges of each bar correspond to the perihelion and aphelion of the body, respectively, hence long bars denote high orbital eccentricity . The radius of
5481-402: The host Earth . Earth's two apsides are the farthest point, aphelion , and the nearest point, perihelion , of its orbit around the host Sun. The terms aphelion and perihelion apply in the same way to the orbits of Jupiter and the other planets , the comets , and the asteroids of the Solar System . There are two apsides in any elliptic orbit . The name for each apsis is created from
5568-528: The mainland has been encouraged by the Chinese government since the 1950s. They are the official forms used in mainland China and Singapore , while traditional characters are officially used in Hong Kong , Macau , and Taiwan . Simplification of a component—either a character or a sub-component called a radical —usually involves either a reduction in its total number of strokes , or an apparent streamlining of which strokes are chosen in what places—for example,
5655-402: The orbit) is the line connecting the two extreme values . Apsides pertaining to orbits around the Sun have distinct names to differentiate themselves from other apsides; these names are aphelion for the farthest and perihelion for the nearest point in the solar orbit. The Moon 's two apsides are the farthest point, apogee , and the nearest point, perigee , of its orbit around
5742-463: The orbital motions of the planets around the Sun. The words are formed from the prefixes peri- (Greek: περί , near) and apo- (Greek: ἀπό , away from), affixed to the Greek word for the Sun, ( ἥλιος , or hēlíos ). Various related terms are used for other celestial objects . The suffixes -gee , -helion , -astron and -galacticon are frequently used in the astronomical literature when referring to
5829-429: The orbiting body when the latter is located: 1) at the periapsis point, or 2) at the apoapsis point (compare both graphics, second figure). The line of apsides denotes the distance of the line that joins the nearest and farthest points across an orbit; it also refers simply to the extreme range of an object orbiting a host body (see top figure; see third figure). In orbital mechanics , the apsides technically refer to
5916-588: The perihelion passage. For example, using an epoch of 1996, Comet Hale–Bopp shows perihelion on 1 April 1997. Using an epoch of 2008 shows a less accurate perihelion date of 30 March 1997. Short-period comets can be even more sensitive to the epoch selected. Using an epoch of 2005 shows 101P/Chernykh coming to perihelion on 25 December 2005, but using an epoch of 2012 produces a less accurate unperturbed perihelion date of 20 January 2006. Numerical integration shows dwarf planet Eris will come to perihelion around December 2257. Using an epoch of 2021, which
6003-409: The perturbing effects of the planets and other objects in the solar system (Milankovitch cycles). On a very long time scale, the dates of the perihelion and of the aphelion progress through the seasons, and they make one complete cycle in 22,000 to 26,000 years. There is a corresponding movement of the position of the stars as seen from Earth, called the apsidal precession . (This is closely related to
6090-570: The phase-modulated orbit. These accelerations were conducted 16, 24, and 48 hours into the missions, during which several orbit adjustments and attitude maneuvers were carried out so as to ensure the probes' capture by lunar gravity. After operating in the Earth-Moon orbit for 4–5 days, each probe entered a lunar acquisition orbit. After entering their target orbits, conducting three braking maneuvers and experiencing three different orbit phases, Chang'e 1 and Chang'e 2 carried out their missions. Lunar orbiters have to remain properly oriented with respect to
6177-409: The plane of Earth's orbit. Indeed, at both perihelion and aphelion it is summer in one hemisphere while it is winter in the other one. Winter falls on the hemisphere where sunlight strikes least directly, and summer falls where sunlight strikes most directly, regardless of the Earth's distance from the Sun. In the northern hemisphere, summer occurs at the same time as aphelion, when solar radiation
6264-482: The planet takes longer to orbit from June solstice to September equinox than it does from December solstice to March equinox. Therefore, summer in the northern hemisphere lasts slightly longer (93 days) than summer in the southern hemisphere (89 days). Astronomers commonly express the timing of perihelion relative to the First Point of Aries not in terms of days and hours, but rather as an angle of orbital displacement,
6351-466: The planets of the Solar System as seen from above the northern pole of Earth's ecliptic plane , which is coplanar with Earth's orbital plane . The planets travel counterclockwise around the Sun and for each planet, the blue part of their orbit travels north of the ecliptic plane, the pink part travels south, and dots mark perihelion (green) and aphelion (orange). The first image (below-left) features
6438-496: The prefixes ap- , apo- (from ἀπ(ό) , (ap(o)-) 'away from') for the farthest or peri- (from περί (peri-) 'near') for the closest point to the primary body , with a suffix that describes the primary body. The suffix for Earth is -gee , so the apsides' names are apogee and perigee . For the Sun, the 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
6525-467: The program was the operation of the TT&C system, because its transmission capability needed sufficient range to communicate with the probes in lunar orbit. China's standard satellite telemetry had a range of 80,000 kilometers (50,000 miles), but the distance between the Moon and the Earth can exceed 400,000 kilometers (250,000 miles) when the Moon is at apogee . In addition, the Chang'e probes had to carry out many attitude maneuvers during their flights to
6612-415: The program's chief commander and chief designer. Sun Jiadong , an aerospace engineer , is the program's general designer and Sun Zezhou is deputy general designer. The leading program manager is Luan Enjie. The Chinese Lunar Exploration Program is divided into four main operational phases, with each mission serving as a technology demonstrator in preparation for future missions. International cooperation in
6699-430: The public and quickly fell out of official use. It was ultimately formally rescinded in 1986. The second-round simplifications were unpopular in large part because most of the forms were completely new, in contrast to the familiar variants comprising the majority of the first round. With the rescission of the second round, work toward further character simplification largely came to an end. In 1986, authorities retracted
6786-476: The same set of simplified characters as mainland China. The first round was promulgated by the Ministry of Education in 1969, consisting of 498 simplified characters derived from 502 traditional characters. A second round of 2287 simplified characters was promulgated in 1974. The second set contained 49 differences from the mainland China system; these were removed in the final round in 1976. In 1993, Singapore adopted
6873-461: The second round completely, though they had been largely fallen out of use within a year of their initial introduction. That year, the authorities also promulgated a final version of the General List of Simplified Chinese Characters . It was identical to the 1964 list save for 6 changes—including the restoration of 3 characters that had been simplified in the first round: 叠 , 覆 , 像 ; the form 疊
6960-504: The short term, such dates can vary up to 2 days from one year to another. This significant variation is due to the presence of the Moon: while the Earth–Moon barycenter is moving on a stable orbit around the Sun, the position of the Earth's center which is on average about 4,700 kilometres (2,900 mi) from the barycenter, could be shifted in any direction from it—and this affects the timing of
7047-547: The side facing away from the Sun, imposed strict requirements for temperature control in the design of the detectors. Given the conditions of the three-body system of the Earth, Moon and a space probe , the orbit design of lunar orbiters is more complicated than that of Earth-orbiting satellites, which only deal with a two-body system. The Chang'e 1 and Chang'e 2 probes were first sent into highly elliptical Earth orbits. After separating from their launch vehicles, they entered an Earth-Moon transfer orbit through three accelerations in
7134-405: The so-called longitude of the periapsis (also called longitude of the pericenter). For the orbit of the Earth, this is called the longitude of perihelion , and in 2000 it was about 282.895°; by 2010, this had advanced by a small fraction of a degree to about 283.067°, i.e. a mean increase of 62" per year. For the orbit of the Earth around the Sun, the time of apsis is often expressed in terms of
7221-861: The suit. In 2021, China and Russia announced they will be building a Moon base together, also formally invited more countries and international organizations to join their International Lunar Research Station (ILRS) project being developed by the two nations, as an alternative to the American Artemis Program . China announced on April 24 the International Lunar Research Station Cooperation Organization (ILRSCO) with members including: China, Russia, South Africa, Belarus, Azerbaijan, Venezuela, Pakistan and Egypt. Planned hard landing Planned soft landing The biggest challenge in Phase I of
7308-817: The traditional character 強 , with 11 strokes is standardised as 强 , with 12 strokes, which is a variant character. Such characters do not constitute simplified characters. The new standardized character forms shown in the Characters for Publishing and revised through the Common Modern Characters list tend to adopt vulgar variant character forms. Since the new forms take vulgar variants, many characters now appear slightly simpler compared to old forms, and as such are often mistaken as structurally simplified characters. Some examples follow: The traditional component 釆 becomes 米 : The traditional component 囚 becomes 日 : The traditional "Break" stroke becomes
7395-405: 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., for satellites), then the orbital parameters are independent of the smaller mass. When used as a suffix—that is, -apsis —the term can refer to the two distances from the primary body to
7482-491: The two distances is the length of the semi-minor axis b . The geometric mean of the two limiting speeds is which is the speed of a body in a circular orbit whose radius is a {\displaystyle a} . Orbital elements such as the time of perihelion passage are defined at the epoch chosen using an unperturbed two-body solution that does not account for the n-body problem . To get an accurate time of perihelion passage you need to use an epoch close to
7569-461: Was abandoned, confirmed by a speech given by Zhou Enlai in 1958. In 1965, the PRC published the List of Commonly Used Characters for Printing [ zh ] (hereafter Characters for Printing ), which included standard printed forms for 6196 characters, including all of the forms from the 1956 scheme. A second round of simplified characters was promulgated in 1977, but was poorly received by
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