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Lissajous Orbit
In orbital mechanics, a Lissajous orbit (), named after Jules Antoine Lissajous, is a quasi-periodic orbital trajectory that an object can follow around a Lagrangian point of a three-body system without requiring any propulsion. Lyapunov orbits around a Lagrangian point are curved paths that lie entirely in the plane of the two primary bodies. In contrast, Lissajous orbits include components in this plane and perpendicular to it, and follow a Lissajous curve. Halo orbits also include components perpendicular to the plane, but they are periodic, while Lissajous orbits are usually not. In practice, any orbits around Lagrangian points , , or are dynamically unstable, meaning small departures from equilibrium grow over time. As a result, spacecraft in these Lagrangian point orbits must use their propulsion systems to perform orbital station-keeping. Although they are not perfectly stable, a modest effort of station keeping keeps a spacecraft in a desired Lissajous orbit for a long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilkinson Microwave Anisotropy Probe
The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP and Explorer 80), was a NASA spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang. Headed by Professor Charles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University. The WMAP spacecraft was launched on 30 June 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorer program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002), who had been a member of the mission's science team. After nine years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by European Space Agency ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herschel Space Observatory
The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA). It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Telescope in 2021. Herschel carries a mirror and instruments sensitive to the far infrared and submillimetre wavebands (55–672 µm). Herschel was the fourth and final cornerstone mission in the Horizon 2000 programme, following ''SOHO''/'' Cluster II'', ''XMM-Newton'' and ''Rosetta''. The observatory was carried into orbit by an Ariane 5 in May 2009, reaching the second Lagrangian point (L2) of the Earth–Sun system, from Earth, about two months later. Herschel is named after Sir William Herschel, the discoverer of the infrared spectrum and planet Uranus, and his sister and collaborator Caroline Herschel. The observatory was capable of seeing the coldest and dustiest objects in space; for example, cool cocoons where stars form and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Scientific
World Scientific Publishing is an academic publisher of scientific, technical, and medical books and journals headquartered in Singapore. The company was founded in 1981. It publishes about 600 books annually, along with 135 journals in various fields. In 1995, World Scientific co-founded the London-based Imperial College Press together with the Imperial College of Science, Technology and Medicine. Company structure The company head office is in Singapore. The Chairman and Editor-in-Chief is Dr Phua Kok Khoo, while the Managing Director is Doreen Liu. The company was co-founded by them in 1981. Imperial College Press In 1995 the company co-founded Imperial College Press, specializing in engineering, medicine and information technology, with Imperial College London. In 2006, World Scientific assumed full ownership of Imperial College Press, under a license granted by the university. Finally, in August 2016, ICP was fully incorporated into World Scientific under the new imprint ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libration Point Orbit
In orbital mechanics, a libration point orbit (LPO) is a quasiperiodic orbit around a Lagrange point. Libration is a form of orbital motion exhibited, for example, in the Earth–Moon system. Trojan bodies also exhibit libration dynamics. Two varieties of libration point orbits amenable to Lyapunov stability are halo orbits and Lissajous orbits The James Webb Space Telescope (JWST) is in a libration point orbit around the L2 Langrange point of the Sun, and Earth-Moon barycenters. Because libration point orbits are quasiperiodic, the telescope must make frequent small burns to maintain proximity to the L2 point, as part of orbital station keeping In astrodynamics, orbital station-keeping is keeping a spacecraft at a fixed distance from another spacecraft or celestial body. It requires a series of orbital maneuvers made with thruster burns to keep the active craft in the same orbit as its ..., limiting the lifespan of the telescope due to depletion of fuel reserves. Early simulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andy Weir
Andrew Taylor Weir (born June 16, 1972) is an American novelist and former computer programmer. His 2011 novel '' The Martian'' was adapted into the 2015 film of the same name directed by Ridley Scott. He received the John W. Campbell Award for Best New Writer in 2016 and his 2021 novel '' Project Hail Mary'' was a finalist for the 2022 Hugo Award for Best Novel. Early life Weir was raised in Milpitas, California. His father, John Weir, was a physicist at Sandia National Laboratories, and his mother was an electrical engineer. He was an only child, and his parents divorced when he was eight. Weir grew up reading classic science fiction such as the works of Arthur C. Clarke and Isaac Asimov. At the age of 15, he began working as a computer programmer for Sandia. After high school, Weir studied computer science at the University of California, San Diego, though he did not graduate. He worked as a programmer for several software companies, including AOL, Palm, MobileIron, and Bli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artemis (novel)
''Artemis'' is a 2017 science fiction novel written by Andy Weir. It takes place in the late 2080s in Artemis, the first and so far only city on the Moon. It follows the life of porter and smuggler Jasmine "Jazz" Bashara as she gets caught up in a conspiracy for control of the city. The audiobook edition (published by Amazon.com) is narrated by Rosario Dawson. Plot In Artemis, the first city on the Moon, porter and part-time smuggler Jasmine "Jazz" Bashara is offered an opportunity by a regular client, wealthy businessman Trond Landvik, to assist him with a new business venture. While meeting with Trond, Jazz briefly encounters an associate of his named Jin Chu who attempts to conceal a case marked with the name ZAFO. Trond intends to take over Sanchez Aluminum, which currently enjoys a lucrative permanent contract with the city for free energy in exchange for providing the city's entire oxygen supply as a by-product from aluminum production. Trond asks Jazz to sabotage the com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen Baxter (author)
Stephen Baxter (born 13 November 1957) is an English hard science fiction author. He has degrees in mathematics and engineering. Writing style Strongly influenced by SF pioneer H. G. Wells, Baxter has been Vice-President of the international H. G. Wells Society since 2006. His fiction falls into three main categories of original work plus a fourth category, extending other authors' writing; each has a different basis, style, and tone. Baxter's "Future History" mode is based on research into hard science. It encompasses the Xeelee Sequence, which consists of nine novels (including the ''Destiny's Children'' trilogy and Vengeance/Redemption duology that is set in alternate timeline), plus three volumes collecting the 52 short pieces (short stories and novellas) in the series, all of which fit into a single timeline stretching from the Big Bang singularity of the past to his ''Timelike Infinity'' singularity of the future. These stories begin in the present day and end when th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur C
Arthur is a common male given name of Brythonic origin. Its popularity derives from it being the name of the legendary hero King Arthur. The etymology is disputed. It may derive from the Celtic ''Artos'' meaning “Bear”. Another theory, more widely believed, is that the name is derived from the Roman clan '' Artorius'' who lived in Roman Britain for centuries. A common spelling variant used in many Slavic, Romance, and Germanic languages is Artur. In Spanish and Italian it is Arturo. Etymology The earliest datable attestation of the name Arthur is in the early 9th century Welsh-Latin text ''Historia Brittonum'', where it refers to a circa 5th to 6th-century Briton general who fought against the invading Saxons, and who later gave rise to the famous King Arthur of medieval legend and literature. A possible earlier mention of the same man is to be found in the epic Welsh poem ''Y Gododdin'' by Aneirin, which some scholars assign to the late 6th century, though this is still a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunstorm (novel)
''Sunstorm'' is a 2005 science fiction novel co-written by British writers Arthur C. Clarke and Stephen Baxter. It is the second book in the series '' A Time Odyssey''. The books in this series are often likened to the ''Space Odyssey'' series, although the ''Time Odyssey'' novels ostensibly deal with time where the ''Space Odyssey'' novels dealt with space. The first book in the series was '' Time's Eye''. Plot summary ''Sunstorm'' opens with the last chapter of '' Time's Eye'' as its initial chapter, and Bisesa Dutt is in London, reunited with her daughter. It is 9 June 2037, the day after her helicopter was shot down in the North Western Frontier Province of Pakistan. The five years that she spent on Mir, an alternate Earth, are now only memories (though the fact that her body has aged five years since 8 June 2037, will eventually serve as some confirmation of her story). In the meantime, a major solar event occurs on 9 June, disrupting virtually all of the E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, extraterrestrial life, sentient artificial intelligence, cybernetics, certain forms of immortality (like mind uploading), and the singularity. Science fiction predicted several existing inventions, such as the atomic bomb, robots, and borazon, whose names entirely match their fictional predecessors. In addition, science fiction might serve as an outlet to facilitate future scientific and technological innovations. Science fiction can trace its roots to ancient mythology. It is also related to fantasy, horror, and superhero fiction and contains many subgenres. Its exact definition has long been disputed among authors, critics, scholars, and readers. Science fiction, in literature, film, television, and other media, has beco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo Orbit
A halo orbit is a periodic, three-dimensional orbit near one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is that it can be orbited by a Lissajous orbit or a halo orbit. These can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal force on a spacecraft. Halo orbits exist in any three-body system, e.g., a Sun–Earth–orbiting satellite system or an Earth–Moon–orbiting satellite system. Continuous "families" of both northern and southern halo orbits exist at each Lagrange point. Because halo orbits tend to be unstable, stationkeeping may be required to keep a satellite on the orbit. Most satellites in halo orbit serve scientific purposes, for example as space telescopes. Definition and history Robert W. Farquhar first used the name "halo" in 1966 for orbits arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chang'e 4
Chang'e 4 (; ) is a robotic spacecraft mission, part of the second phase of the Chinese Lunar Exploration Program. China achieved humanity's first soft landing on the far side of the Moon, on 3 January 2019. A communication relay satellite, , was first launched to a halo orbit near the Earth–Moon L2 point in May 2018. The robotic lander and ''Yutu-2'' () rover were launched on 7 December 2018 and entered lunar orbit on 12 December 2018, before landing on the Moon's far side. The mission is the follow-up to Chang'e 3, the first Chinese landing on the Moon. The spacecraft was originally built as a backup for Chang'e 3 and became available after Chang'e 3 landed successfully in 2013. The configuration of Chang'e 4 was adjusted to meet new scientific and performance objectives. Like its predecessors, the mission is named after Chang'e, the Chinese Moon goddess. In November 2019, Chang’e 4 mission team was awarded Gold Medal by the Royal Aeronautical Society. In October ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
