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  • Indian National Satellite (INSAT) system is a multi-agency, multipurpose application satellite system for domestic communication, meteorology observation & data relay, nationwide direct satellite TV broadcasting & radio-programme distribution.
  • Also provides services in the areas of disaster warning a distress alert i.e. search & rescue missions. INSAT system was commissioned with the launch of INSAT-1B in August 1983 (INSAT-1A, the first satellite was launched in April 1982 but could not fulfil the mission).
  • INSAT is the largest domestic communication system in the Asia Pacific Region with more than ten satellites in service — INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT, INSAT-4A, INSAT-4B, INSAT­40 AND INSAT-4CR.
  • It is a joint venture of the Department of Space, Department of Telecommunications, India Meteorological Department, All India Radio (AIR) and Doordarshan.
  • The overall coordination and management of INSAT system rests with the Secretary-level INSAT Coordination Committee.
  • The INSAT-1 series satellites were built by Ford Aerospace Corporation of the USA under contract with the Department of Space.
  • Of the four satellites of the INSAT-1 series, INSAT-1D is still operational. Now it is well past its nominal life and is already in an inclined orbit, the inclination amounting to more than 1°.
  • This handicap necessitates continuous tracking by ground systems, which service operators prefer not to undertake for reasons of reliability.
  • INSAT satellites provide 199 transponders in various bands (C, S, Extended C and Ku) to serve the television and communication needs of India.
  • Some of the satellites also have the Very High Resolution Radiometer (VHRR), CCD cameras for metrological imaging. KALPANA-1 is an exclusive meteorological satellite.
  • The satellites also incorporate transponder for receiving distress alert signals for search and rescue missions in the South Asian and Indian Ocean Region, as ISRO is a member of the Cospas-Sarsat programme.
  • The satellites are monitored and controlled by Master Control Facilities that exist in Hassan and Bhopal.
  • The INSAT system is Geo-synchronous (GS) in nature as opposed to that of the RSS, which are Sun-synchronous.
  • A GS Satellite is a common satellite rotating in circular equatorial orbit at a fixed altitude of about 36,000 km, goes around the earth once in about 24 hours.
  • As the earth takes the same time to rotate on its axis, the satellite appears stationery and hence the name Geo-Synchronous Satellite (GSS).
  • The Communication satellites are normally GSS. The high equatorial altitude gives them coverage of maximum surface area of the earth by spending minimum fuel and thus, such an orbit is chosen to lengthen the life of the satellite.
  • Moreover, GS movement allows the sat to have a continuous view of the same part of the earth, thereby giving continuous application benefits.

Given below are details of in service geo stationary satellites:


  • It is the last of the five satellites in INSAT-2 series. It carries seventeen C-band and lower extended C-band transponders providing zonal and global coverage with an Effective Isotropic Radiated Power (EIRP) of 36 dBW.
  • It also carries a Very High Resolution Radiometer (VHRR) with imaging capacity in the visible, thermal infrared and water vapour channels.
  • It also has with it a Charge Coupled Device (CCD) camera providing 1×1 km ground resolution in the Visible, Near Infrared and Shortwave Infrared bands.


  • The multipurpose satellite, INSAT-3A, was launched by Ariane in April 2003. It carries with it 12 Normal C-band transponders, 6 Ku-band transponders, a Very High Resolution Radiometer (VHRR), a CCD camera, a Data Relay Transponder (DRT) and a satellite aided search and rescue payload.


  • Launched in January 2002, INSAT-3C is positioned at 74 degree East longitude. INSAT-3C payloads include 24 Normal C-band transponders, six Extended C-band transponders, two S-band transponders and an MSS payload similar to that on INSAT­3B.


  • INSAT-3D is a meteorological, data relay and satellite aided search and rescue satellite developed by the Indian Space Research Organisation and was launched successfully on 26 July 2013 using an Ariane 5 ECA launch vehicle from French Guiana.
  • The satellite has many new technology elements like star sensor, micro stepping Solar Array Drive Assembly (SADA) to reduce the spacecraft disturbances and Bus Management Unit (BMU) for control and telecom and telemetry function.
  • It also incorporates new features of bi-annual rotation and Image and Mirror motion compensations for improved performance of the meteorological payloads.
  • The satellite has 3 payloads: Meteorological (MET), Data Relay Transponder (DRT), and Satellite Aided Search and Rescue (SAS&R). INSAT-3D was launched along with AlphaSat, which is Europe’s largest telecommunication satellite.


  • Launched in September 2003. INSAT-3E is positioned at 55 degree East longitude and carries 24 Normal C-band transponders and 12 Extended C-band transponders.
  • The satellite has been decommissioned and gone out of service from April 2014.


  • KALPANA-1 is an exclusive meteorological satellite launched by PSLV in September 2002.
  • It carries very high resolution radiometer (VHRR) and a data relay transponder (DRT) payloads to provide meteorological services Its original name was METSAT


  • Launched by the second flight of GSLV in May 2003 GSAT-2 is located at 48 degree East longitude and carries four Normal C-band transponders, two Ku-band transponders and a MSS payload.


  • Configured for audio-visual medium employing digital interactive classroom lessons and multimedia content, EDUSAT was launched by GSLV in September 2004.
  • Its transponders and their ground coverage are specially configured to cater to the educational requirements.
  • The satellite carries a Ku-band transponder, five Ku-band spot beam transponders for South, West, Central, North and North East regional coverage and six Extended C-band transponders.


  • It was launched in December 2005 by the European Ariane launch vehicle. It carries 12 Ku-band transponders and 12 C-band transponders.
  • Tata Sky, a joint venture between the TATA Group and STAR uses INSAT-4A for distributing their Direct To Home Digital Television services across India. COMMUNICATION SATELLITE PROGRAMME (INSAT SYSTEM)


  • It was launched in March 2007 by the European Ariane launch vehicle. It carries 12 Ku-band and 12 C-band transponders.
  • The national space agency ISRO has allotted nearly seven Ku band transponders to Sun Direct; a DTH service provider from South India, and the other five to Doordarshan’s DD Direct.
  • 12 transponders in the C band are for TV, radio and telecommunication purposes


  • On July 7 2010, ISRO has reported a glitch in the operation of INSAT 4B. Power was not flowing from one of the solar panels to the satellite bus from July 7 night, which led to switching off 50 per cent of the transponders on board the satellite.


  • India launched the INSAT 40 on 10 July 2006 from Sriharikota .The heaviest satellite to be launched from the Indian soil, INSAT-4C weighed 2168 kg, and was designed to last for 10 years.
  • The satellite would have given a boost to Direct-to-Home television services, video picture transmission and digital satellite news gathering, and would have also provided space for connectivity.
  • However, the launch was unsuccessful as the GSLV-F02 carrying the satellite veered from its projected path 60 seconds after launch, and was self-destructed over the Bay of Bengal.
  • The failure is being attributed to pressure of one of the strap-on motors dropping to zero pressure in the first stage of operation, thus causing it to deviate it from its path by 10 degrees.


  • INSAT-4CR was launched on 2 September 2007 by GSLV-F04. It is a replacement satellite of INSAT-4C which was lost when GSLV-F02 failed and had to be destroyed on its course.
  • It carries 12 Ku-band transponders. It also incorporates a Ku-band Beacon as an aid to tracking the satellite.
  • On 8 September 2007 ISRO reported the satellite had reached a near geosynchronous orbit, and would be stabilized in its intended orbital position of 74 degrees E longitude by 15 September.
  • The satellite is designed for a mission life in of ten years. However, the ISRO later refuted this claim dismissing it as false. This satellite is used by /keel Digital TV and Sun Direct DTH to broadcast their DTH services.


  • GSAT-8, India’s advanced communication satellite, is a high power communication satellite being inducted in the INSAT system.
  • Weighing about 3100 kg at lift-off, GSAT-8 ;s configured to carry 24 high power transponders in Ku-band and a two-channel GPS Aided Geo Augmented Navigation (GAGAN) payload operating in L1 and L5 hands.


  • GSAT-12 is communication satellite developed by the ISRO, as part of INSAT system. GSAT-12 had been launched on 15 July 2011 from SDSC, Sriharikota.
  • The satellite had been injected by PSLV-C17(XL) into sub-Geosynchronous Transfer Orbit and later be transferred to Geostationary orbit of 36000km by a series of manoeuvres using on board Liquid engine motors.
  • GSA T- 12 is considered to be a replacement of the aged satellite INSAT-3B and provide services like tele-medicine, point of sale transactions and satellite Internet access.

GSAT — 10

  • GSAT-10 is an Indian communication satellite which was launched by Ariane-5ECA carrier rocket in 2012.
  • It will field C and Ka band transponders and includes a navigation payload to augment GAGAN (GPS Aided Geo Augmented Navigation) capacity.


  • GSAT-14 is an Indian communications satellite launched on 5 January 2014. It is expected to replace the GSAT-3 satellite, which was launched in 2004.
  • GSAT-14 was launched by a GSLV Mk II, which incorporated an Indian-built cryogenic engine on the third stage. GSAT-14 is part of the GSAT series of satellites.
  • Constructed by 1SRO, it is based around the I-2K satellite bus. The spacecraft has a design life of 12 years,
  • The satellite carries six Ku-band and six Extended C-band transponders to provide coverage of the whole of India.
  • The satellite is expected to provide enhanced broadcasting services over the GSAT-3 satellite. GSAT-14 also carries two Ka-band beacons which will be used to conduct research into how weather affects Ka-band satellite communications.
  • Fiber optic gyro, active pixel sun sensor, round type bolometer and field programmable gate array based earth sensors and thermal control coating experiments are new technologies which were flown as experiments in the satellite.
  • The satellite is powered by two solar arrays, generating 2,600 watts of power. The launch marked the first successful flight test of the CE-7.5, India’s first cryogenically-fuelled rocket engine. COMMUNICATION SATELLITE PROGRAMME (INSAT SYSTEM)



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