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Experimental Geodetic Payload
Ajisai (Japanese: あじさい, meaning "Hydrangea") is a Japanese satellite sponsored by NASDA, launched in 1986 on the first flight of the H-I rocket. It is also known as the Experimental Geodetic Satellite (EGS), as it carried the Experimental Geodetic Payload (EGP). History EGP was launched from the Tanegashima Space Center on August 12, 1986 at 20:45 GMT (August 13, 05:45 local time). The launch vehicle was the first H-I rocket. After launch, the spacecraft was given the International Designator 1986-061A and Satellite Catalog Number 16908. Structure EGP is entirely passive, and operates by reflecting sunlight or ground-based lasers.Curtis, Anthony R (1989). ''Space Almanac,'' Arcsoft Publishers. The satellite is a 685-kg hollow sphere with a diameter of 2.15 meters, and the surface is covered with 318 mirrors for reflecting sunlight and 1436 corner reflectors for reflecting laser beams. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrangea
''Hydrangea'', () commonly named the hortensia, is a genus of over 75 species of flowering plants native to Asia and the Americas. By far the greatest species diversity is in eastern Asia, notably China, Korea, and Japan. Most are shrubs tall, but some are small trees, and others lianas reaching up to by climbing up trees. They can be either deciduous or evergreen, though the widely cultivated temperate species are all deciduous. ''Hydrangea'' is derived from Greek and means ‘water vessel’ (from ''húdōr'' "water" + ''ángos'' or ''angeîon'' "vessel"), in reference to the shape of its seed capsules. The earlier name, ''Hortensia'', is a Latinised version of the French given name Hortense, honoring French astronomer and mathematician Nicole-Reine Hortense Lepaute. This claim is disputed in page 88 on citation 10 at Nicole-Reine Hortense Lepaute page, which says: "Larousse considers this an injustice, and remarks that it has led many persons to the erroneous notion tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degree (angle), degrees. For a satellite orbiting a planet, the plane of reference is usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites Of Japan
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by propulsion, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Laser Ranging Satellites
In satellite laser ranging (SLR) a global network of observation stations measures the round trip time of flight of ultrashort pulses of light to satellites equipped with retroreflectors. This provides instantaneous range measurements of millimeter level precision which can be accumulated to provide accurate measurement of orbits and a host of important scientific data. The laser pulse can also be reflected by the surface of a satellite without a retroreflector, which is used for tracking space debris. Satellite laser ranging is a proven geodetic technique with significant potential for important contributions to scientific studies of the earth/atmosphere/ocean system. It is the most accurate technique currently available to determine the geocentric position of an Earth satellite, allowing for the precise calibration of radar altimeters and separation of long-term instrumentation drift from secular changes in ocean topography. Its ability to measure the variations over time in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Passive Satellites
List of passive satellites is a listing of inert or mostly inert satellites, mainly of the Earth. This includes various reflector type satellites typically used for geodesy and atmospheric measurements. Passive satellites *Calsphere **Calsphere 1A **Calsphere 2 **Calsphere 3 **Calsphere 4 **Calsphere 4A **Calsphere 5 *Dragsphere 1 *Dragsphere 2 *Enoch * Explorer 9 *GFZ-1 *Humanity Star * LCS-1 *PAGEOS *PAMS-STU, see STS-77 *POPACS *Reflector * PasComSat *Rigid Sphere 1 (AVL-802H) *Rigid Sphere 2 *Sfera Dedicated laser ranging satellites Mostly passive satellites *Starshine 3, see Athena I * Echo project **Echo 1 (Echo 1A) **Echo 2 * Elon Musk's Tesla Roadster * Hayabusa2 **Deployable camera 3 (DCAM3) **Small Carry-On Impactor (SCI) **Target Marker B **Target Marker A **Target Marker E (Explorer) **Target Marker C (Sputnik/Спутник) * Tianwen-1 ** Tianwen-1 Deployable Camera 1 ** Tianwen-1 Remote Camera **Tianwen-1 Deployable Camera 2 See also * List of laser ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starlette And Stella
Starlette (''Satellite de taille adaptée avec réflecteurs laser pour les études de la terre'', or ) and Stella are nearly identical French geodetic and geophysical satellites. Starlette was launched on 6 February 1975 and Stella on 26 September 1993. Starlette was the first passive laser satellite developed. Background Starlette's development dates back to at least 1972, when scientists at the Centre national d'études spatiales (CNES) were trying to determine a payload for the upcoming first flight of the new Diamant BP4 rocket. After consulting with the Smithsonian Astrophysical Observatory, CNES scientists decided to create a small geodetic satellite optimized for tracking by laser ranging. The project was approved within a few months after a feasibility study by the French atomic agency CEA determined the dense uranium core could be made nearly non-radioactive by using depleted uranium. The Groupe de recherches en géodésie spatiale (GRGS; Space Geodesy Research Grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LAGEOS
LAGEOS, Laser Geodynamics Satellite or Laser Geometric Environmental Observation Survey, are a series of two scientific research satellites designed to provide an orbiting laser ranging benchmark for geodynamical studies of the Earth. Each satellite is a high-density passive laser reflector in a very stable medium Earth orbit (MEO). Function and operation The spacecraft are aluminum-covered brass spheres with diameters of and masses of , covered with 426 cube-corner retroreflectors, giving them the appearance of giant golf balls. Of these retroreflectors, 422 are made from fused silica glass while the remaining 4 are made from germanium to obtain measurements in the infrared for experimental studies of reflectivity and satellite orientation. They have no on-board sensors or electronics, and are not attitude-controlled. They orbit at an altitude of , well above low Earth orbit and well below geostationary orbit, at orbital inclinations of 109.8 and 52.6 degrees. Measurements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesy
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as '' planetary geodesy''). Geodynamical phenomena, including crustal motion, tides and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques and relying on datums and coordinate systems. The job title is geodesist or geodetic surveyor. History Definition The word geodesy comes from the Ancient Greek word ''geodaisia'' (literally, "division of Earth"). It is primarily concerned with positioning within the temporally varying gravitational field. Geodesy in the German-speaking world is divided into "higher geodesy" ( or ), which is concerned with measuring Earth on the global scale, and "practical geodes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars. For celestial objects in general, the sidereal period ( sidereal year) is referred to by the orbital period, determined by a 360° revolution of one body around its primary, e.g. Earth around the Sun, relative to the fixed stars projected in the sky. Orbital periods can be defined in several ways. The tropical period is more particularly about the position of the parent star. It is the basis for the solar year, and respectively the calendar year. The synodic period incorporates not only the orbital relation to the parent star, but also to other celestial objects, making it not a mere different approach to the orbit of an object around its parent, but a period of orbital relations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called Transponder (satellite communications), transponders. Many satellites use a Satellite bus, standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming Satellite constellation, constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio Broadcast relay station, relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Earth Orbit
A medium Earth orbit (MEO) is an geocentric orbit, Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO) – between above sea level.''Catalog of Earth Satellite Orbits'' NASA Earth Observatory. 4 September 2009. Accessed 2 May 2021. The boundary between MEO and LEO is an arbitrary altitude chosen by accepted convention, whereas the boundary between MEO and HEO is the particular altitude of a geosynchronous orbit, in which a satellite takes 24 hours to circle the Earth, the same period as the Earth’s own rotation. All satellites in MEO have an orbital period of less than 24 hours, with the minimum period (for a circular orbit at the lowest MEO altitude) about 2 hours. Satellites in MEO or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
