|
Weak Stability Boundary
Weak stability boundary (WSB), including Low-energy transfer, is a concept introduced by Edward Belbruno in 1987. The concept explained how a spacecraft could change orbits using very little fuel. Weak stability boundary is defined for the three-body problem. This problem considers the motion of a particle P of negligible mass moving with respect to two larger bodies, P1, P2, modeled as point masses, where these bodies move in circular or elliptical orbits with respect to each other, and P2 is smaller than P1. The force between the three bodies is the classical Newtonian gravitational force. For example, P1 is the Earth, P2 is the Moon and P is a spacecraft; or P1 is the Sun, P2 is Jupiter and P is a comet, etc. This model is called the restricted three-body problem. The weak stability boundary defines a region about P2 where P is temporarily captured. This region is in position-velocity space. Capture means that the Kepler energy between P and P2 is negative. This is also call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-energy Transfer
A low-energy transfer, or low-energy trajectory, is a route in space that allows spacecraft to change orbits using significantly less fuel than traditional transfers. These routes work in the Earth–Moon system and also in other systems, such as between the moons of Jupiter. The drawback of such trajectories is that they take longer to complete than higher-energy (more-fuel) transfers, such as Hohmann transfer orbits. Low-energy transfers are also known as Weak Stability Boundary trajectories, and include ballistic capture trajectories. Low-energy transfers follow special pathways in space, sometimes referred to as the Interplanetary Transport Network. Following these pathways allows for long distances to be traversed for little change in velocity, or . Example missions Missions that have used low-energy transfers include: * ''Hiten'', from JAXA * '' SMART-1'', from ESA * ''Genesis'', from NASA. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hiten (spacecraft)
The Hiten spacecraft (ひてん, ), given the English name Celestial Maiden and known before launch as MUSES-A ( Mu Space Engineering Spacecraft A), part of the MUSES Program, was built by the Institute of Space and Astronautical Science of Japan and launched on January 24, 1990. It was Japan's first lunar probe, the first robotic lunar probe since the Soviet Union's Luna 24 in 1976, and the first lunar probe launched by a country other than the Soviet Union or the United States. The spacecraft was named after flying heavenly beings in Buddhism. Hiten was to be placed into a highly elliptical Earth orbit with an apogee of 476,000 km, which would swing past the Moon. However, the injection took place with a delta-v deficit of 50 m/s, resulting in an apogee of only 290,000 km. The deficiency was corrected and the probe continued on its mission. On the first lunar swing-by, Hiten released a small orbiter, Hagoromo (はごろも, named after the feather mantle of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schrödinger Equation
The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the subject. The equation is named after Erwin Schrödinger, who postulated the equation in 1925, and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933. Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics. Given a set of known initial conditions, Newton's second law makes a mathematical prediction as to what path a given physical system will take over time. The Schrödinger equation gives the evolution over time of a wave function, the quantum-mechanical characterization of an isolated physical system. The equation can be derived from the fact that the time-evolution operator must be unitary, and must therefore be generated by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
39P/Oterma
39P/Oterma is a currently inactive List of periodic comets, periodic comet with an orbital period of nearly 20 years that stays outside the orbit of Jupiter. The comet nucleus, nucleus has a diameter around 4–5 km. It was last observed in August 2021 and came to perihelion in July 2023 while 1.2 Astronomical unit, AU from Jupiter. It will finish the modest 39P/Oterma#CA2025, approach to Jupiter in January 2025 and will next come to perihelion in July 2042 at distance of 5.9 AU from the Sun. Opposition (astronomy), Opposition will occur on 11 November 2023. Discovery The comet was discovered by Liisi Oterma at Iso-Heikkilä Observatory, Turku University Observatory, Finland on a photo plate on 8 April 1943 as a faint object of 15th Apparent magnitude, magnitude in the constellation of Virgo (constellation), Virgo. Its orbit was calculated by Leland Cunningham, L. E. Cunningham and R. N. Thomas who derived an orbit with a small Orbital eccentricity, eccentricity, a Apsis, perihel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Resonance
In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationship is found between a pair of objects (binary resonance). The physical principle behind orbital resonance is similar in concept to pushing a child on a swing, whereby the orbit and the swing both have a natural frequency, and the body doing the "pushing" will act in periodic repetition to have a cumulative effect on the motion. Orbital resonances greatly enhance the mutual gravitational influence of the bodies (i.e., their ability to alter or constrain each other's orbits). In most cases, this results in an ''unstable'' interaction, in which the bodies exchange momentum and shift orbits until the resonance no longer exists. Under some circumstances, a resonant system can be self-correcting and thus stable. Examples are the 1:2:4 resonance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panspermia
Panspermia () is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraft carrying unintended contamination by microorganisms.Forward planetary contamination like '' Tersicoccus phoenicis'', that has shown resistance to methods usually used in spacecraft assembly clean rooms: Panspermia is a fringe theory with little support amongst mainstream scientists. Critics argue that it does not answer the question of the origin of life but merely places it on another celestial body. It is also criticized because it cannot be tested experimentally. Panspermia proposes (for example) that microscopic lifeforms which can survive the effects of space (such as extremophiles) can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Panspermia studies c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithopanspermia
Panspermia () is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraft carrying unintended contamination by microorganisms.Forward planetary contamination like ''Tersicoccus phoenicis'', that has shown resistance to methods usually used in spacecraft assembly clean rooms: Panspermia is a fringe theory with little support amongst mainstream scientists. Critics argue that it does not answer the question of the origin of life but merely places it on another celestial body. It is also criticized because it cannot be tested experimentally. Panspermia proposes (for example) that microscopic lifeforms which can survive the effects of space (such as extremophiles) can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Panspermia studies co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Cluster
Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clustered groups of stars, generally containing fewer than a few hundred members, and are often very young. Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy, but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound; they are then known as a stellar association, sometimes also referred to as a ''moving group''. Star clusters visible to the naked eye include the Pleiades, Hyades, and 47 Tucanae. Open cluster Open clusters are very different from globular clusters. Unlike the spherically distributed globulars, they are confined to the galactic plane, and are almost always found wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysics
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–''what'' they are, rather than ''where'' they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, ''astrophysicists'' apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BepiColombo
BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The mission comprises two satellites launched together: the Mercury Planetary Orbiter (MPO) and ''Mio'' (Mercury Magnetospheric Orbiter, MMO). The mission will perform a comprehensive study of Mercury, including characterization of its magnetic field, magnetosphere, and both interior and surface structure. It was launched on an Ariane 5 rocket on 20 October 2018 at 01:45 UTC, with an arrival at Mercury planned for on 5 December 2025, after a flyby of Earth, two flybys of Venus, and six flybys of Mercury. The mission was approved in November 2009, after years in proposal and planning as part of the European Space Agency's Horizon 2000+ programme; it is the last mission of the programme to be launched. Names ''BepiColombo'' is named after Giuseppe "Bepi" Colombo (1920–1984), a scientist, mathematician and engineer at the University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danuri
The Korea Pathfinder Lunar Orbiter (KPLO), officially Danuri, is South Korea's first lunar orbiter. The orbiter, its science payload and ground control infrastructure are technology demonstrators. The orbiter will also be tasked with surveying lunar resources such as water ice, uranium, helium-3, silicon, and aluminium, and produce a topographic map to help select future lunar landing sites. The mission was launched on 4 August 2022 on a Falcon 9 Block 5 launch vehicle. It was inserted into orbit around the Moon on 16 December 2022 (UTC). Name On 23 May 2022, the South Korean Ministry of Science and ICT officially named the Korea Pathfinder Lunar Orbiter (시험용 달 궤도선, 試驗用月軌道船) as "Danuri" (다누리). Danuri is a portmanteau of two Korean words, ''dal'' (달) which means moon and ''nurida'' (누리다) which means enjoy. According to the ministry, this new name implies a big hope and desire for the success of South Korea's first Moon mis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAPSTONE
CAPSTONE (Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) is a lunar orbiter that will test and verify the calculated orbital stability planned for the Lunar Gateway space station. The spacecraft is a 12-unit CubeSat that will also test a navigation system that will measure its position relative to NASA's Lunar Reconnaissance Orbiter (LRO) without relying on ground stations. It was launched on 28 June 2022, arrived in lunar orbit on 14 November 2022, and is scheduled to orbit for six months. Background The Lunar Gateway is an in-development space station being planned by several national space agencies since at least 2018, including NASA, European Space Agency (ESA) and Canadian Space Agency (CSA). The Gateway is planned to be placed in a novel lunar orbit that has not been used previously, where it is expected to serve as a communications hub, science laboratory, short-term habitation module, and holding area for rovers and other robo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.png "Click for more on -> Schrödinger Equation")
