Envisat and Other Earth Resource Satellites History and Development (Especially for GATE-Geospatial 2022)

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Envisat (European Space Agency)

  • The Envisat (Environmental Satellite) satellite is an Earth-observing satellite built by the European Space Agency. It was launched on March 1,2002 aboard an Ariane 5 into a Sun synchronous polar orbit at a height of 790 km ( 10 km) . It orbits the Earth in about 101 minutes with a repeat cycle of 35 days.
EnviSat - EoPortal Directory - Satellite Missions
  • Envisat carries an array of nine Earth-observation instruments that gather information about the earth (land, water, ice, and atmosphere) using a variety of measurement principles.
  • The ASAR instrument onboard the satellite operated at C-band (5.3 GHz) and was capable of acquiring data in multiple modes (image, alternating polarization, wave, ScanSAR (wide swath) , and ScanSAR (global monitoring) ) at various incidence angles and in several polarizations. Envisat was launched as an Earth observation satellite.
  • Its objective was to service the continuity of European Remote-Sensing Satellite missions, providing additional observational parameters to improve environmental studies.
  • In working towards the global and regional objectives of the mission, numerous scientific disciplines currently use the data acquired from the different sensors on the satellite to study such things as atmospheric chemistry, ozone depletion, biological oceanography, ocean temperature and colour, wind waves, hydrology (humidity, floods) , agriculture and arboriculture, natural hazards, digital elevation modelling (using interferometry) , monitoring of maritime traffic, atmospheric dispersion modelling (pollution) , cartography and study of snow and ice.
  • Resourcesat 2A is a satellite dedicated to mapping natural resources, tracking agriculture, water resources, soil contamination, and the growth of Indian cities.
    • It is a follow-up to the Resource sat 1 and Resource sat 2 spacecraft launched by India in 2003 and 2011.
    • Designed for a five-year mission, RESOURCESAT 2A carries three cameras to take visible and near-infrared pictures, and India՚s space agency said the new craft will extend the data pipeline previously fed by Resource sat 2 launched in 2011.
  • Cartosat 2B is India՚s third satellite with a peak imaging resolution of less than one meter. The 1,530 pound (694 kg) spacecraft՚s black-and-white camera has a resolution of 0.8 meters, or approximately 2.6 feet, giving users close views of cities, neighborhoods, natural resources and military sites around the world.
    • The imagery will have applications in resource mapping, urban planning, transportation studies, water monitoring, and crop inventories, according to ISRO.
    • Cartosat 2C is a military Indian satellite able to resolve objects on the ground as small as 60 centimeters (2 feet) .
    • ISRO did not disclose the Cartosat 2 series satellite՚s capabilities or reveal a specific name for the imaging platform. With a launch weight of 1,604 pounds (more than 727 kilograms) , the satellite carries visible cameras to capture black-and-white and color imagery during a five-year mission.
    • The imagery sent by the CARTOSAT 2C will be useful for cartographic applications, urban and rural applications, coastal land use and regulation, utility management like road network monitoring, water distribution, creation of land use maps, precision study, change detection to bring out geographical and manmade features, and various other Land Information System (LIS) and Geographical Information System (GIS) applications
  • Gaofen 8 is an optical satellite with a high resolution imaging payload. Reportedly, the duties of the satellite are country surveying, disaster response, agriculture mapping, city planning, land ownership marking and road network planning.
  • HYSIS (Hyper Spectral Imaging Spectrometer) is a small Indian earth observation satellite to study the earth՚s surface in visible, near infrared and shortwave infrared regions of the electromagnetic spectrum. Developed by ISRO.
  • Nusat 4 (Ada, Aleph-1 4) and NUSAT 5 (Maryam, Aleph-1 5) are 2 Argentinian satellites part of the Aleph-1 constellation that is being developed and operated by Satellogic S. A.
    • The Aleph-1 constellation will consist of up to 25 satellites. The two satellites are almost identical to each other and have a mass of 37 kg, with dimensions .
    • The primary objective of the mission is to commercially provide earth observation images to the general public in the visible and infrared parts of the spectrum.
  • Tansat is a Chinese satellite designed to track greenhouse gases in Earth՚s atmosphere. Using a near-infrared spectrometer, the Tansat satellite will track regional and global concentrations of carbon dioxide down to four parts per million, generating monthly maps of where the densest greenhouse gas levels are distributed worldwide.
    • The Tansat spacecraft can turn to point its instruments straight down at Earth, pivot to aim toward the sun՚s glint off ocean and land surfaces, and conduct targeted observations of carbon-emitting cities and heavy industrial regions. The satellite will cover every part of the planet at least once every 16 days during its three-year mission.
  • Ziyuan 3 - 2 is a civilian Earth imaging craft to be operated by China՚s Satellite Surveying and Mapping Application Center, a follow-up mission to the first Ziyuan 3 mapping spacecraft launched in January 2012.
    • Ziyuan 3 - 2 will be used in land resources surveys, natural disaster prevention, agricultural development, water resources management and urban planning, among other tasks.
    • Ziyuan 3 - 2՚s cameras will collect high-resolution imagery in 3D and in color, with the ability to resolve objects on Earth՚s surface less than 3 meters (10 feet) in size. The satellite is designed for a five-year mission.
  • Sentinel 2B is a European environmental and Earth observation spacecraft, the fifth Copernicus satellite to launch since deployments began in 2014.
    • The Sentinel 2 satellites provide the Copernicus program՚s optical component, specializing in mapping land surfaces, monitoring crops and forests, and detecting pollution in lakes, streams and coastal waters.
    • Sentinel 2A and 2B are roughly analogous to the U. S. government՚s Landsat satellite series, but with the ability to image the entire planet at faster tempos, a characteristic known as revisit time.
    • Sentinel 2B՚s orbit is positioned 180 degrees away from Sentinel 2A, and the satellites together will see every point on the planet at least once every five days. The revisit time will be cut to around three days at Europe՚s latitude, and as short as one day in parts of Scandinavia and Canada.
  • Oceansat-2 is an Indian remote sensing satellite envisaged to provide service continuity for the operational users of OCM (Ocean Color Monitor) data as well as to enhance the application potential in other areas.
    • The main objectives of OceanSat-2 are to study surface winds and ocean surface strata, observation of chlorophyll concentrations, monitoring of phytoplankton blooms, study of atmospheric aerosols and suspended sediments in the water.

Other Earth Resource Satellites

  • Earth observation satellite or Earth remote sensing satellite is satellite specifically designed for Earth observation from orbit, similar to spy satellites but intended for non-military uses such as environmental monitoring, meteorology, map making.
  • NASA satellites help scientists study Earth and space. Satellites looking toward Earth provide information about clouds, oceans, land and ice. They also measure gases in the atmosphere, such as ozone and carbon dioxide, and the amount of energy that Earth absorbs and emits. Starting with IRS-1A in 1988, ISRO has launched many operational remote sensing satellites.
  • Today, India has one of the largest constellations of remote sensing satellites in operation. Currently, ⚹ thirteen ⚹ operational satellites are in Sun-synchronous orbit – RESOURCESAT-1,2, 2A CARTOSAT-1,2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, Megha-Tropiques, SARAL and SCATSAT-1, and ⚹ four ⚹ in Geostationary orbit- INSAT-3D, Kalpana & INSAT 3A, INSAT -3DR.
  • Varieties of instruments have been flown onboard these satellites to provide necessary data in a diversified spatial, spectral and temporal resolutions to cater to different user requirements in the country and for global usage.
  • The data from these satellites are used for several applications covering agriculture, water resources, urban planning, rural development, mineral prospecting, environment, forestry, ocean resources and disaster management

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