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PAGEOS
PAGEOS (PAssive Geodetic Earth Orbiting Satellite) was a balloon satellite which was launched by NASA in June 1966. Design PAGEOS had a diameter of exactly , consisted of a thick mylar plastic film coated with vapour deposited aluminium enclosing a volume of and was used for the Weltnetz der Satellitentriangulation (Worldwide Satellite Triangulation Network) – a global cooperation organized by Hellmut Schmid (Switzerland & USA) 1969-1973. Finished in 1974, the network connected 46 stations (3000–5000 km distance) of all continents with an accuracy of 3–5 m (approx. 20 times better than terrestrial triangulations at that time). Orbit The PAGEOS spacecraft was placed into a polar orbit (inclination 85–86°) with a height of approx. 4000 km, which had gradually lowered during its 9 years of operation. The satellite partly disintegrated in July 1975, which was followed by a second break-up that occurred in January 1976 resulting in the release of a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAGEOS Satellite - GPN-2000-001896
PAGEOS (PAssive Geodetic Earth Orbiting Satellite) was a balloon satellite which was launched by NASA in June 1966. Design PAGEOS had a diameter of exactly , consisted of a thick mylar plastic film coated with vapour deposited aluminium enclosing a volume of and was used for the Weltnetz der Satellitentriangulation (Worldwide Satellite Triangulation Network) – a global cooperation organized by Hellmut Schmid (Switzerland & USA) 1969-1973. Finished in 1974, the network connected 46 stations (3000–5000 km distance) of all continents with an accuracy of 3–5 m (approx. 20 times better than terrestrial triangulations at that time). Orbit The PAGEOS spacecraft was placed into a polar orbit (inclination 85–86°) with a height of approx. 4000 km, which had gradually lowered during its 9 years of operation. The satellite partly disintegrated in July 1975, which was followed by a second break-up that occurred in January 1976 resulting in the release of a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balloon Satellite
A balloon satellite is inflated with gas after it has been put into orbit. It is also occasionally referred to as a "satelloon", which is a trademarked name owned by Gilmore Schjeldahl's G.T. Schjeldahl Company. List of balloon satellites abbreviations: * pcr = passive communications reflector, satellite reflects microwave signals. * ado = atmospheric density observations * spc = solar pressure calculations, estimate impact of solar wind on orbit. * tri = satellite triangulation, measuring the Earth's surface. * SC = Sensors and camera for earth curvature images Echo 1 and Echo 2 balloon satellites The first flying body of this type was Echo 1, which was launched into a high orbit on August 12, 1960, by the United States. It originally had a spherical shape measuring , with a thin metal-coated plastic shell made of Mylar. It served for testing as a "passive" communication and geodetic satellite. Its international COSPAR number was 6000901 (9th satellite launched in 1960, 1s ... [...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] |
Satellite Triangulation
Stellar triangulation is a method of geodesy and of its subdiscipline space geodesy used to measure Earth's geometric shape. Stars were first used for this purpose by the Finnish astronomer Yrjö Väisälä in 1959, who made astrometric photographs of the night sky at two stations together with a lighted balloon probe between them. Even this first step showed the potential of the method, as Väisälä got the azimuth between Helsinki and Turku (a distance of 150 km) with an accuracy of 1″. Soon the method was successfully tested by ballistic rockets and for some special satellites. Adequate computer programs were written for * the astrometric reduction of the photographic plates, * the intersection of the "observation planes" containing the stations and the targets, * and the least-squares adjustment of stellar-terrestrial networks with redundancy. The advantages of stellar triangulation were the possibility to cross far distances (terrestrial observations are restrict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echo 1
Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, were metalized balloon satellites acting as passive reflectors of microwave signals. Communication signals were transmitted from one location on Earth and bounced off the surface of the satellite to another Earth location. The first transmissions using Echo were sent from Goldstone, California to Holmdel, New Jersey on 12 August 1960. The last Echo satellite deorbited and burned up in the atmosphere on 7 June 1969.Astronautix.com, ''Echo'' Background The concept of using orbital satellites to relay communications predated space travel, first being advanced by |
Hellmut Schmid
Hellmut H. Schmid (12 September 1914 – 27 April 1998) was Professor of geodesy and photogrammetry on the ETH Zürich (Switzerland), where he emerited in 1985. In the 1950s, he worked on research projects of space exploration in the United States. Between 1968 and 1974, he promoted the first intercontinental network of satellite geodesy. Focal points of his research in Europa * Geodetic measurement methods at the V2 project in Peenemünde (~1942) * Beginnings of satellite geodesy 1959 * Theory of analytical photogrammetry and matrix/ IT developments (1950s, USA) * High precision evaluation of photogram (ca. 1965-1978) * Worldwide Satellite Triangulation Network (1969-1973 (publ. 1974): first regular intercontinental network, 46 stations (3000–5000 km apart), pioneering accuracy (±3m) * Contributions to the least-squares adjustment, network optimization, Block triangulation * Optimization of coordinate transformations (~1975) * Development of 3D intersection meth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passive Satellites
Passive may refer to: * Passive voice, a grammatical voice common in many languages, see also Pseudopassive * Passive language, a language from which an interpreter works * Passivity (behavior), the condition of submitting to the influence of one's superior * Passive-aggressive behavior, resistance to following through with expectations in interpersonal or occupational situations * Passive income, income resulting from cash flow received on a regular basis * Passive immunity, the transfer of active humoral immunity * Passive experience, observation lacking recipricol interaction; and wrought with delusion of control. Science and technology * Passivation (chemistry), process of making a material "passive" in relation to another material prior to using the materials together * Passivity (engineering) a property of engineering systems, particularly in analog electronics and control systems * Passive solar building design, which uses (or avoids) sunlight as an energy source without ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites Formerly Orbiting Earth
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] |
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] |
World Geodetic System
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also describes the associated Earth Gravitational Model (EGM) and World Magnetic Model (WMM). The standard is published and maintained by the United States National Geospatial-Intelligence Agency. Definition The coordinate origin of WGS 84 is meant to be located at the Earth's center of mass; the uncertainty is believed to be less than . The WGS 84 meridian of zero longitude is the IERS Reference Meridian, European Organisation for the Safety of Air Navigation and IfEN: WGS 84 Implementation Manual, p. 13. 1998 5.3 arc seconds or east of the Greenwich meridian at the latitude of the Royal Observatory. (This is related to the fact that the local gravity field at Greenwich doesn't point exactly through the Earth's center of mass, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Ellipsoid
An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy, and the geosciences. Various different ellipsoids have been used as approximations. It is a spheroid (an ellipsoid of revolution) whose minor axis (shorter diameter), which connects the geographical North Pole and South Pole, is approximately aligned with the Earth's axis of rotation. The ellipsoid is defined by the ''equatorial axis'' (''a'') and the ''polar axis'' (''b''); their radial difference is slightly more than 21 km, or 0.335% of ''a'' (which is not quite 6,400 km). Many methods exist for determination of the axes of an Earth ellipsoid, ranging from meridian arcs up to modern satellite geodesy or the analysis and interconnection of continental geodetic networks. Amongst the different set of data used in national surveys are several of special importance: the Bessel ellipsoid of 1841, the internation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polaris
Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris ( Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98, it is the brightest star in the constellation and is readily visible to the naked eye at night. The position of the star lies less than 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the Northern Sky makes it useful for navigation. As the closest Cepheid variable its distance is used as part of the cosmic distance ladder. The revised '' Hipparcos'' stellar parallax gives a distance to Polaris of about , while the successor mission ''Gaia'' gives a distance of about . Calculations by other methods vary widely. Although appearing to the naked eye as a single point of light, Polaris is a triple star system, composed of the primary, a yellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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