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GPS Occultation
Radio occultation (RO) is a remote sensing technique used for measuring the physical properties of a planetary atmosphere or ring system. Atmospheric radio occultation Atmospheric radio occultation relies on the detection of a change in a radio signal as it passes through a planet's atmosphere, i.e. as it is occulted by the atmosphere. When electromagnetic radiation passes through the atmosphere, it is refracted (or bent). The magnitude of the refraction depends on the gradient of refractivity normal to the path, which in turn depends on the density gradient. The effect is most pronounced when the radiation traverses a long atmospheric limb path. At radio frequencies the amount of bending cannot be measured directly; instead the bending can be calculated using the Doppler shift of the signal given the geometry of the emitter and receiver. The amount of bending can be related to the refractive index by using an Abel transform on the formula relating bending angle to refractivity. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refracted
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelength ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spire Global
Spire Global, Inc. is a space-to-cloud data and analytics company that specializes in the tracking of global data sets powered by a large constellation of nanosatellites, such as the tracking of maritime, aviation and weather patterns. The company currently operates a fleet of more than 110 CubeSats, the second largest commercial constellation by number of satellites, and the largest by number of sensors. The satellites are integrally designed and built in-house. It has launched more than 140 satellites to orbit since its creation. The company has offices in San Francisco, Boulder, Washington DC, Glasgow, Luxembourg, Singapore, and Cambridge (Ontario). History Early Years Spire was originally known as NanoSatisfi Inc. NanoSatisfi was founded in June 2012 in San Francisco by International Space University graduates Peter Platzer, Jeroen Cappaert and Joel Spark as part of ArduSat, a project aiming to “democratize access to space”. Tests for early prototypes were conducte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MetOp
Metop (Meteorological Operational satellite) is a series of three polar-orbiting meteorological satellites developed by the European Space Agency (ESA) and operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The satellites form the space segment component of the overall EUMETSAT Polar System (EPS), which in turn is the European half of the EUMETSAT / NOAA Initial Joint Polar System (IJPS). The satellites carry a payload comprising 11 scientific instruments and two which support Cospas-Sarsat Search and Rescue services. In order to provide data continuity between Metop and NOAA Polar Operational Environmental Satellites (POES), several instruments are carried on both fleets of satellites. Metop-A, launched on 19 October 2006, is Europe's first polar orbiting satellite used for operational meteorology. With respect to its primary mission of providing data for Numerical Weather Prediction, studies have shown that ''Metop-A'' data ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sentinel-6 Michael Freilich
The Sentinel-6 Michael Freilich (S6MF) is a radar altimeter satellite developed in partnership between several European and American organizations. It is part of the Jason satellite series and is named after Michael Freilich. S6MF includes synthetic-aperture radar altimetry techniques to improve ocean topography measurements, in addition to rivers and lakes. Spacecraft The Sentinel-6 program includes two identical satellites, to be launched five years apart, Sentinel-6 Michael Freilich, which launched on 21 November 2020, and Sentinel-6B, which will launch in 2025. These satellites will measure sea level change from space, which have been measured without interruption since 1992. Formerly called ''Sentinel-6A'' and ''Jason-CS A'' (''Jason Continuity of Service-A''), it was renamed in honor of the former director of NASA Earth Science Division, Michael Freilich, who was instrumental in advancing space-based ocean measurements. It follows the most recent U.S.-European s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceansat
Oceansat is a series of earth observation satellites built, launched, and operated by Indian Space Research Organisation, and dedicated to oceanography and atmospheric studies. Oceansat satellites facilitate a range of applications including documenting chlorophyll concentration, phytoplankton blooms, atmospheric aerosols and particulate matter as well as marine weather forecast to predict cyclones. Satellites Oceansat-1 OceanSat-1 was the first Indian satellite built specifically for oceanographic applications. The satellite carried an Ocean Colour Monitor (OCM) and a multi-frequency scanning microwave radiometer. Oceansat-1 was launched on board a PSLV rocket on 26 May 1999. It was capable of detecting eight spectrums ranging from 400 nm to 885 nm, all in the visible or near infrared spectrums. The second, the Multi-frequency Scanning Microwave Radiometer, collects data by measuring microwave radiation passing through the atmosphere over the ocean. This off ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Recovery And Climate Experiment
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The GRACE Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. By measuring gravity anomalies, GRACE showed how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE was a collaborative endeavor involving the Center for Space Research at the University of Texas at Austin, NASA's Jet Propulsion Laboratory, the German Aerospace Center and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory was responsible for the overall mission management under the NASA ESSP (Earth System Science Pathfinder) program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CHAMP (satellite)
Challenging Minisatellite Payload (CHAMP) was a German satellite launched July 15, 2000 from Plesetsk, Russia and was used for atmospheric and ionospheric research, as well as other geoscientific applications, such as GPS radio occultation, gravity field determination, and studying the Earth's magnetic field. CHAMP was managed by GeoForschungsZentrum (GFZ) Potsdam. The spacecraft is the first application of Astrium's "Flexbus" platform; GRACE was the second. A heavily modified version flew as the GOCE mission. Spacecraft Instruments An onboard BlackJack Global Positioning System (GPS) Flight Receiver, provided by JPL, enables the use of satellite to satellite tracking for vehicle positioning. To remove the effect of external, non-gravitational forces (e.g., atmospheric drag, solar radiation pressure) the satellite features an internal 3-axis STAR accelerometer. Independent verification of orbital position is enabled by a passive Laser Retro Reflector (LRR), which al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FORMOSAT-7/COSMIC-2
COSMIC-2 also known as FORMOSAT-7, is the constellation of satellites for meteorology, ionosphere, climatology, and space weather research. FORMOSAT-7 is a joint US-Taiwanese project including National Space Organization (NSPO) on the Taiwanese side and the National Oceanic and Atmospheric Administration (NOAA) and the United States Air Force (USAF) on the US side. FORMOSAT-7 is the successor of FORMOSAT-3 The six satellites of the constellation were launched 25 June 2019 on a Falcon Heavy rocket. They reached their designated mission orbits in February 2021, after eighteen months of gradual orbital adjustments. Full operational capability was achieved in October 2021. Pre-launch On the morning of 14 April 2019, President Tsai Ing-wen traveled to Hsinchu City to take part in send-off activities for the Formosat-7 satellite. She commended the hard work and accomplishments of the research and development team, and hailed Formosat-7 as a milestone in promoting Taiwan's technologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CLARREO
CLARREO (Climate Absolute Radiance and Refractivity Observatory) is a high-priority NASA decadal survey mission, originally selected as such by the National Research Council in 2007.National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. National Academies Press, Washington, D.C., 426pp, 2007. The CLARREO mission is intended to provide a metrology laboratory in orbit to accurately quantify and attribute Earth's climate change (see List of climate research satellites). The mission is also designed to transfer its high accuracy to other spaceborne sensors. It would serve as a reference calibration standard in orbit, making climate trends apparent in their data sets by 2055, within a 30-year time frame after its planned launch in the 2020's. These measurements may go on to enable testing, validation, and improvement of climate model prediction. Due to funding cuts in announced for the 2012 budget, the CLARREO mission ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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