|
GOCE
The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) was the first of European Space Agency, ESA's Living Planet Programme satellite, heavy satellites intended to map in unprecedented detail the Earth's gravity field. The spacecraft's primary instrumentation was a highly sensitive gravity Gravity gradiometry, gradiometer consisting of three pairs of accelerometers which measured gravitational gradients along three orthogonal axes. Launched on 17 March 2009, GOCE mapped the deep structure of the Earth's Mantle (geology), mantle and probed hazardous volcanic regions. It brought new insight into ocean behaviour; this in particular, was a major driver for the mission. By combining the gravity data with information about sea surface height gathered by other satellite altimeters, scientists were able to track the direction and speed of Geostrophic current, geostrophic ocean currents. The low orbit and high accuracy of the system greatly improved the known accuracy and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geoid
The geoid ( ) is the shape that the ocean surface would take under the influence of the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent. This surface is extended through the continents (such as might be approximated with very narrow hypothetical canals). According to Carl Friedrich Gauss, who first described it, it is the "mathematical figure of the Earth", a smooth but irregular surface whose shape results from the uneven distribution of mass within and on the surface of Earth. It can be known only through extensive gravitational measurements and calculations. Despite being an important concept for almost 200 years in the history of geodesy and geophysics, it has been defined to high precision only since advances in satellite geodesy in the late 20th century. The geoid is often expressed as a geoid undulation or geoidal height above a given reference ellipsoid, which is a slightly flattene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockot
Rokot ( meaning ''Rumble'' or ''Boom''), also transliterated Rockot, was a Soviet Union (later Russian) space launch vehicle that was capable of launching a payload of into a Earth orbit with 63° inclination. It was based on the UR-100N (SS-19 Stiletto) intercontinental ballistic missile (ICBM), supplied and operated by Khrunichev State Research and Production Space Center. The first launches started in the 1990s from Baikonur Cosmodrome out of a silo. Later commercial launches commenced from Plesetsk Cosmodrome using a launch ramp specially rebuilt from one for the Kosmos-3M launch vehicle. The cost of the launcher itself was about US$15 million in 1999; The contract with European Space Agency (ESA) for launching Swarm in September 2013 was worth €27.1 million (US$36 million). Specifications Rokot's total mass was 107 tonnes, its length 29 metres and its maximum diameter 2.5 metres. The liquid-fueled launch vehicle comprised three stages. The lower two were based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Moisture And Ocean Salinity
Soil Moisture and Ocean Salinity (SMOS) is a satellite which forms part of ESA's Living Planet Programme. It is intended to provide new insights into Earth's water cycle and climate. In addition, it is intended to provide improved weather forecasting and monitoring of snow and ice accumulation.ESA's water mission SMOS European Space AgencySMOS Project Team The Soil Moisture and Ocean Salinity (SMOS) Mission European Space AgencySMOS Special Issue of ESA Bulleti [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Gradiometry
Gravity gradiometry is the study of variations (gravitational anomaly, ''anomalies'') in the Earth's gravity field via measurements of the spatial gradient of gravitational acceleration. The gravity gradient tensor is a 3x3 tensor; it is given in coordinates by the Jacobian matrix of the acceleration vector (g=[g_x g_y g_z]^T), totaling 9 Scalar (physics), scalar quantities: : G=\nabla g = \begin \partial/\partial & \partial/\partial & \partial/\partial\\ \partial/\partial & \partial/\partial & \partial/\partial\\ \partial/\partial & \partial/\partial & \partial/\partial \end It has dimension (physics), dimension of square reciprocal time, in unit of measurement, units of s−2 (or mm−1s−2). Gravity gradiometry is used by oil and mineral prospectors to measure the density of the Bedrock, subsurface, effectively by measuring the rate of change of gravitational acceleration due to underlying rock properties. From this information it is possible to build a picture of subsurface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living Planet Programme
The Living Planet Programme (LPP) is a programme within the European Space Agency which is managed by the Earth Observation Programmes Directorate. LPP consists of two classes of Earth observation missions (listed below) including research missions known as Earth Explorers, and the Earth Watch class of missions whose objective is to develop support operational applications such as numerical weather forecasting or resource management. List of Earth Explorer missions Selected missions Launched missions * GOCE – Gravity Field and Steady-State Ocean Circulation Explorer; it was launched on 17 March 2009. It reentered the atmosphere on 11 November 2013. * SMOS – Soil Moisture and Ocean Salinity satellite will study ocean salinity and soil moisture; it was launched on 2 November 2009. * CryoSat – a program designed to map the Earth's ice cover. ** CryoSat-1 was lost in 2005 when the Russian Rokot launch vehicle malfunctioned and was terminated. ** CryoSat-2 was launched on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mann Eddy
The Mann Eddy is a very small feature of ocean currents in the Atlantic. It is a persistent clockwise circulation in the middle of the North Atlantic ocean, specifically "a mesoscale anticyclone, adjacent to the path of the North Atlantic Current (NAC) in the Newfoundland basin". The eddy has persisted since its initial discovery in 1967. The peak in the Eddy Kinetic Energy (EKE) associated with the Mann Eddy lies at around 43°N 43°W, within the North Atlantic Current travelling to the North along the Grand Banks The Grand Banks of Newfoundland are a series of underwater plateaus south-east of the island of Newfoundland on the North American continental shelf. The Grand Banks are one of the world's richest fishing grounds, supporting Atlantic cod, swordfi .... The oceanographer Dr Rory Bingham from Newcastle University (UK) describes it as "a persistent pocket of water in the Atlantic that just goes around and around." References Physical oceanography Currents of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Propulsion
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. An ion thruster creates a cloud of positive ions from a neutral gas by ionizing it to extract some electrons from its atoms. The ions are then accelerated using electricity to create thrust. Ion thrusters are categorized as either electrostatic or electromagnetic. Electrostatic thruster ions are accelerated by the Coulomb force along the electric field direction. Temporarily stored electrons are reinjected by a ''neutralizer'' in the cloud of ions after it has passed through the electrostatic grid, so the gas becomes neutral again and can freely disperse in space without any further electrical interaction with the thruster. By contrast, electromagnetic thruster ions are accelerated by the Lorentz force to accelerate all species (free electrons as well as positive and negative ions) in the same direction whatever their electric charge, and are specifically referred to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Surface Height
Ocean surface topography or sea surface topography, also called ocean dynamic topography, are highs and lows on the ocean surface, similar to the hills and valleys of Earth's land surface depicted on a topographic map. These variations are expressed in terms of average sea surface height (SSH) relative to Earth's geoid. The main purpose of measuring ocean surface topography is to understand the large-scale ocean circulation. Time variations Unaveraged or instantaneous sea surface height (SSH) is most obviously affected by the tidal forces of the Moon and by the seasonal cycle of the Sun acting on Earth. Over timescales longer than a year, the patterns in SSH can be influenced by ocean circulation. Typically, SSH anomalies resulting from these forces differ from the mean by less than ± at the global scale. Other influences include changing interannual patterns of temperature, salinity, waves, tides and winds. Ocean surface topography can be measured with high accuracy and pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Earth Orbit
A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around , while the farthest in LEO, before medium Earth orbit (MEO), have an altitude of 2,000 km, about one-third of the Earth radius, radius of Earth and near the beginning of the Van Allen radiation belt#Inner belt, inner Van Allen radiation belt. The term ''LEO region'' is used for the area of space below an altitude of (about one-third of Earth's radius). Objects in orbits that pass through this zone, even if they have an apogee further out or are sub-orbital spaceflight, sub-orbital, are carefully tracked since they present a collision risk to the many LEO satellites. No human spaceflights other than the lunar missions of the Apollo program (1968-1972) have gone beyond L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fins
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foil (fluid mechanics), foils that produce lift (force), lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fins are also used to Fin (extended surface), increase surface areas for heat transfer purposes, or simply as ornamentation. Fins first evolved on fish as a means of locomotion. Fish fins are used to generate thrust and control the subsequent motion. Fish and other aquatic animals, such as cetaceans, actively propel and steer themselves with pectoral fin, pectoral and Caudal fin, tail fins. As they swim, they use other fins, such as dorsal fin, dorsal and anal fins, to achieve stability and refine their maneuvering.Helfman G, Collette BB, Facey DE and Bowen BW (2009"Functional morphology of locomotion and feeding" Chapter 8, pp. 101–116. In:''The Diversity of Fishes: Biology'', John Wiley & Sons. . The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EADS Astrium
Astrium was a European aerospace company and subsidiary of the European Aeronautic Defence and Space Company (EADS), headquartered in Paris. It designed, developed and manufactured civil and military space systems and provided related services from 2006 to 2013. In 2012, Astrium had a turnover of €5.8 billion and 18,000 employees in France, Germany, the United Kingdom, Spain and the Netherlands. Astrium was a member of Institute of Space, its Applications and Technologies. In late 2013 Astrium was merged with Cassidian, the defence division of EADS, as well as Airbus Military to form Airbus Defence and Space. EADS itself was rebranded Airbus Group, with three divisions: Airbus Commercial Aircraft, Airbus Defence and Space, and Airbus Helicopters. Business structure During 2006–2013, the three main areas of activity within Astrium were: * Astrium Satellites for spacecraft and ground segment * EADS Astrium Space Transportation for launchers and orbital infrastructure * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gal (unit)
The gal (symbol: Gal), sometimes called galileo after Galileo Galilei, is a unit of acceleration typically used in precision gravimetry. BIPM ''SI brochure'', 8th ed. 2006Table 9: Non-SI units associated with the CGS and the CGS-Gaussian system of units. The gal is defined as 1 centimeter per second squared (1 cm/s2). The milligal (mGal) and microgal (μGal) are respectively one thousandth and one millionth of a gal. The gal is not part of the International System of Units (known by its French-language initials "SI"). In 1978 the CIPM decided that it was permissible to use the gal "with the SI until the CIPM considers that tsuse is no longer necessary". Use of the gal was deprecated by the standard ISO 80000-3:2006, now superseded. The gal is a derived unit, defined in terms of the centimeter–gram–second (CGS) base unit of length, the centimeter, and the second, which is the base unit of time in both the CGS and the modern SI system. In SI base units, 1 Gal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
