Why in News:

• The ISRO plans to send up atleast eight earth observatory satellites of varied hues and at the rate of almost a month between now and early 2020.

Background:

• Recently ISRO launched EMISAT, the country’s first electronic surveillance satellite. communication satellite GSAT-32 is also in the offing next year to replace GSAT-6A, which was lost in a failed launch.

Recently launched satellite for defence:

EMISAT:

• EMISAT was built by the Defence Research Development Organisation (DRDO).
• It will gather information on enemy radar positions from a sun-synchronous orbit at an altitude of about 750km. EMISAT will achieve this through electromagnetic spectrum measurement. So, the spacecraft
• carries a payload of DRDO’s prestigious Kautilya system for electromagnetic intelligence (ELINT) gathering. Space-based electronic intelligence (ELINT) will add to the situational awareness of the Armed Forces. This will provide location and information of hostile radars placed at the borders.
• This will be another dimension to the current land or aircraft-based ELINT.

GSAT:

• The GSAT satellites are indigenously developed communication satellite, used for digital audio, data and video broadcasting. As of 5 December 2018, 20 GSAT satellites of ISRO have been launched out of which 14 satellites are currently in service.

CARTOSAT:

• The Cartosat series of satellites are a earth observation satellites, indigenously built by India. The Cartosat series is a part of India remote sensing programme. They were specifically launched for Earth’s resource management and monitoring.

RISAT:

• The RISAT series are the first all-weather earth observation satellites from ISRO. They provide all-weather surveillance using synthetic aperture radars (SAR).