Launch of ‘Cloud-Proof’ Earth Observation Spy Satellite RISAT-2B (Download PDF)


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The Indian Space Research Organisation (ISRO) launched an earth observation spy satellite RISAT-2B on 22 May 2019. This spy satellite can take high resolution images of the earth during day and night. The satellite can work under cloudy conditions to keep an eye on terror camps across the border in Pakistan. This satellite will replace its predecessor RISAT-2. RISAT-2 has been actively used by India for monitoring terror camps across the border so as to thwart infiltration bids by the terrorists. The RISAT satellite was first launched in the year 2009.

This is image show in all Season Satellite

This is Image Show in All Season Satellite

This is image show in all Season Satellite

RISAT 2B Features & Overview

  • For surveillance purpose Radar imaging is important, as it does not require sunlight or clear skies to be able to observe its target.

  • A spacecraft equipped with SAR can observe at night and its radio waves can propagate through cloudy skies.

  • The RISAT-2B satellite uses X-band synthetic aperture radar for the first time.

  • Its X-band synthetic aperture radar can give added details such as size of objects on Earth, structures, movement and change.

  • The satellite will be able to detect objects with dimensions of as little as a metre since it has high resolution.

  • This capacity to study small objects and also movement could be useful for surveillance.

  • The satellite could be used for civil and strategic purposes.

  • RISAT-2B will have an inclined orbit of 37 degrees, which will allow more frequent observations over the Indian subcontinent.

  • With ISRO planning to launch four more such radar imaging satellites in a year, its ability to monitor crops and floods as well as engage in military surveillance will be greatly enhanced.

  • Unlike visible light, microwaves have longer wavelength and so will not be susceptible to atmospheric scattering.

  • Microwave radiation can thus easily pass through the cloud cover, haze and dust, and image the ground.

  • With the use of Microwave radiation RISAT-2B satellite will be able to image under almost all weather and environmental conditions.

  • It will be able to image the ground during both day and night since it doesn’t rely on visible light.

  • RISAT-2B will be transmitting hundreds of microwave pulses each second towards the ground and receiving the signals reflected by the objects using radar.

  • The moisture and texture of the object will determine the strength of the microwave signal that gets reflected.

  • While the strength of the reflected signal will help determine different targets, the time between the transmitted and reflected signals will help determine the distance to the object.

  • A Synthetic Aperture Radar (SAR) or SAR, is a coherent mostly airborne or space borne side looking radar system which utilizes the flight path of the platform to simulate an extremely large antenna, and that generates high-resolution remote sensing imagery.

  • The signal processing uses magnitude and phase of the received signals over successive pulses from elements of a synthetic aperture.

  • After a given number of cycles, the stored data is recombined to create a high-resolution image of the terrain being over flown.


  • Crop monitoring during the monsoon season,

  • Forestry mapping for forest fires and deforestation,

  • Flood mapping as part of the national disaster management programme.

  • Well Capable of collecting ground imageries during rains and despite dust, clouds or darkness and during all seasons thereby ensuring continuous and reliable data.

- Published/Last Modified on: August 7, 2019


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