On 26 April 2012, India’s first indigenous all-weather radar imaging satellite (RISAT-1), whose images will facilitate agriculture and disaster management, was launched via PSLV-C19. Radar Satellite-1 (RISAT-1) is a state of the art Microwave Remote Sensing Satellite carrying a Synthetic Aperture Radar (SAR) Payload operating in C-band (5.35 GHz), which enables imaging of the surface features during both day and night under all weather condition.

Uses of RISAT -1

Besides use in the agriculture sector, RISAT-1 could also be used to keep round-the-clock vigil on the country’s borders; however, ISRO said that it would not be used for defence applications. RISAT-2, primarily a spy spacecraft, is already doing that job.

  • RISAT-1’s capability to take images in all weather conditions including fog and haze would be a boon for regions perennially under cloud cover.
  • The satellite carries a C-band Synthetic Aperture Radar (SAR) payload, operating in a multi-polarisation and multi-resolution mode to provide images with coarse, fine and high spatial resolutions respectively.
  • The unique characteristics of SAR enable applications in agriculture, particularly paddy monitoring in kharif season and management of natural disasters like flood and cyclone. The satellite would be particularly useful in Kharif season when cloud-covered atmosphere is frequent. Images taken from the spacecraft of agricultural crops would enable planners with regard to production estimation and forecast.

RISAT-1 : Important Points

  • 1,858 kg RISAT-1 is India’s first microwave remote sensing satellite.
  • RISAT-1 has capability to take images of the earth during day and night as well as in cloudy conditions. Till now, India depended on images from a Canadian satellite as existing domestic remote sensing spacecraft cannot take pictures of earth during cloud cover.
  • The PSLV C-19 was the 20th successive successful flight of PSLV India had in April 2009 launched a Radar Imaging Satellite (RISAT-2) with all weather capability but it was bought from Israel for USD 110 million largely for surveillance purposes.
  • ISRO used PSLV-XL, high-end version, only third such instance, for recent launch. The XL version was earlier used for Chandrayaan-1 and GSAT-12 missions.


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