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Comet Rendezvous Asteroid Flyby
The Comet Rendezvous Asteroid Flyby (CRAF) was a cancelled plan for a NASA-led exploratory mission designed by the Jet Propulsion Laboratory during the mid-to-late 1980s and early 1990s, that planned to send a spacecraft to encounter an asteroid, and then to rendezvous with a comet and fly alongside it for nearly three years. The project was eventually canceled when it went over budget; most of the money still left was redirected to its twin spacecraft, ''Cassini–Huygens'', destined for Saturn, so it could survive Congressional budget cutbacks. Most of CRAF's scientific objectives were later accomplished by the smaller NASA spacecraft ''Stardust'' and Deep Impact, and by ESA's flagship ''Rosetta'' mission. Overview Designed to be the first of the planned Mariner Mark II series of spacecraft, CRAF was to closely examine a comet during a part of its orbit around the Sun. It was to launch a heavily instrumented penetrator/lander into the comet's nucleus to measure temperatures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRAF
CRAF may refer to: * Canadian Charter of Rights and Freedoms * Civil Reserve Air Fleet * Comet Rendezvous Asteroid Flyby * Committee on Radio Astronomy Frequencies * Cuban Revolutionary Armed Forces See also * C-Raf RAF proto-oncogene serine/threonine-protein kinase, also known as proto-oncogene c-RAF or simply c-Raf or even Raf-1, is an enzyme that in humans is encoded by the ''RAF1'' gene. The c-Raf protein is part of the ERK1/2 pathway as a MAP kinase ..., a human enzyme encoded by the RAF1 gene {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
22P/Kopff
Comet Kopff or 22P/Kopff is a periodic comet in the Solar System. Discovered on August 23, 1906, it was named after August Kopff who discovered the comet. The comet was missed on its November 1912 return, but was recovered on its June 1919 return and has been seen at every apparition since. Close approaches to Jupiter in 1938 and 1943 decreased the perihelion distance and orbital period. 22P/Kopff’s last perihelion passage was 18 March 2022. On 13 July 2028 it will pass from Earth. Observations 22P/Kopff was discovered at Königstuhl Observatory on Heidelberg, Germany. Kopff analyzed photographic plates which he exposed on August 20, 1903, against pre-discovery images of the same region. On August 23, 1903, Kopff concluded it to be a comet with an estimated apparent magnitude of 11. On mid-September 1906, the short-period nature of the comet was recognized by a team headed by Kiel Ebell of the Berkeley Astronomical Department. The comet was missed when it made a return on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photograph
A photograph (also known as a photo, image, or picture) is an image created by light falling on a photosensitive surface, usually photographic film or an electronic image sensor, such as a CCD or a CMOS chip. Most photographs are now created using a smartphone/camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating such images is called photography. Etymology The word ''photograph'' was coined in 1839 by Sir John Herschel and is based on the Greek φῶς ('' phos''), meaning "light," and γραφή (''graphê''), meaning "drawing, writing," together meaning "drawing with light." History The first permanent photograph, a contact-exposed copy of an engraving, was made in 1822 using the bitumen-based " heliography" process developed by Nicéphore Niépce. The first photographs of a real-world scene, made using a camera obscura, followed a few years later at Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
449 Hamburga
Hamburga (minor planet designation: 449 Hamburga) is a carbonaceous asteroid from the background population of the intermediate asteroid belt, approximately 75 kilometers in diameter. It was discovered by German astronomers Max Wolf and Friedrich Schwassmann at Heidelberg Observatory on 31 October 1899, and later named after the city of Hamburg in Germany. 449 was a proposed target for the 1980s-1990s space probe mission proposal CRAF. Description ''Hamburga'' is classified as a C-type asteroid and is probably composed of carbonaceous material. It is named for the city of Hamburg in Germany. The name was announced in 1901 during a festival held by the Mathematical Society of Hamburg. 449 Hamburga was identified as one of three asteroids that were likely to be a parent body for chondrites along with 304 Olga and 335 Roberta. All three asteroids were known to have low-albedo (not reflect as much light) and be close to "meteorite producing resonances". Chrondrites are the mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet of the Solar System#Inner solar system, inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type asteroid, C-type, M-type asteroid, M-type, and S-type asteroid, S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres (dwarf planet), Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trajectory
A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete trajectory is defined by position and momentum, simultaneously. The mass might be a projectile or a satellite. For example, it can be an orbit — the path of a planet, asteroid, or comet as it travels around a central mass. In control theory, a trajectory is a time-ordered set of states of a dynamical system (see e.g. Poincaré map). In discrete mathematics, a trajectory is a sequence (f^k(x))_ of values calculated by the iterated application of a mapping f to an element x of its source. Physics of trajectories A familiar example of a trajectory is the path of a projectile, such as a thrown ball or rock. In a significantly simplified model, the object moves only under the influence of a uniform gravitational force field. This c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Launch Window
In the context of spaceflight, launch period is the collection of days and launch window is the time period on a given day during which a particular rocket must be launched in order to reach its intended target. If the rocket is not launched within a given window, it has to wait for the window on the next day of the period. Launch periods and launch windows are very dependent on both the rocket's capability and the orbit to which it is going. A launch period refers to the days that the rocket can launch to reach its intended orbit. A mission could have a period of 365 days in a year, a few weeks each month, a few weeks every 26 months (e.g. Mars launch periods), or a short period time that won't be repeated. A launch window indicates the time frame on a given day in the launch period that the rocket can launch to reach its intended orbit. This can be as short as a second (referred to as an instantaneous window) or even the entire day. For operational reasons, the window almost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Assist
In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense. Gravity assistance can be used to accelerate a spacecraft, that is, to increase or decrease its speed or redirect its path. The "assist" is provided by the motion of the gravitating body as it pulls on the spacecraft. Any gain or loss of kinetic energy and velocity by a passing spacecraft is correspondingly lost or gained by the gravitational body, in accordance with Newton's Third Law. The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon and it was used by interplanetary probes from Mariner 10 onward, including the two Voyager probes' notable flybys of Jupiter and Saturn. Explanation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never far from the Sun, either as morning star or evening star. Aside from the Sun and Moon, Venus is the brightest natural object in Earth's sky, capable of casting visible shadows on Earth at dark conditions and being visible to the naked eye in broad daylight. Venus is the second largest terrestrial object of the Solar System. It has a surface gravity slightly lower than on Earth and has a very weak induced magnetosphere. The atmosphere of Venus, mainly consists of carbon dioxide, and is the densest and hottest of the four terrestrial planets at the surface. With an atmospheric pressure at the planet's surface of about 92 times the sea level pressure of Earth and a mean temperature of , the carbon dioxide gas at Venus's surface is in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centaur (rocket Stage)
The Centaur is a family of rocket propelled upper stages produced by U.S. launch service provider United Launch Alliance, with one main active version and one version under development. The diameter Common Centaur/Centaur III flies as the upper stage of the Atlas V launch vehicle, and the diameter Centaur V is being developed as the upper stage of ULA's new Vulcan rocket. Centaur was the first rocket stage to use liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, a high-energy combination that is ideal for upper stages but has significant handling difficulties. Characteristics Common Centaur is built around stainless steel pressure stabilized balloon propellant tanks with thick walls. It can lift payloads of up to . The thin walls minimize the mass of the tanks, maximizing the stage's overall performance. A common bulkhead separates the LOX and LH2 tanks, further reducing the tank mass. It is made of two stainless steel skins separated by a fiberglass honeyco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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