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Mission typeCommunications
COSPAR ID2007-037A Edit this at Wikidata
SATCAT no.32050
Mission durationPlanned: 12 years
Achieved: 13 years, 2 months, 22 days
Spacecraft properties
Launch mass2,168 kilograms (4,780 lb)
Power3000 W
Start of mission
Launch date2 September 2007, 12:51 (2007-09-02UTC12:51Z) UTC
RocketGSLV Mk.I F04
Launch siteSatish Dhawan SLP
End of mission
DisposalMoved to a graveyard orbit
Deactivated24 November 2020 (2020-11-25)
Orbital parameters
Reference systemGeocentric
Longitude48°E (10 Feb 2017 to 24 Nov 2020)
74°E (till 12 Jan 2017)
Perigee altitude35,026 kilometres (21,764 mi)[1]
Apogee altitude36,235 kilometres (22,515 mi)[1]
Inclination0.15 degrees[1]
Period1,428.12 minutes[1]
Epoch14 September 2007[1]
Band12 Ku band
Coverage areaIndia
TWTA power140 watts
EIRP51.5 decibel-watts

INSAT-4CR was a communications satellite operated by ISRO as part of the Indian National Satellite System. Launched in September 2007, it replaced the INSAT-4C satellite which had been lost in a launch failure the previous year. The satellite was initially stationed in geostationary orbit at a longitude of 74 degrees east, with expected operational life of at least ten years, however this may have been reduced by the underperformance of the Geosynchronous Satellite Launch Vehicle which placed it into orbit. INSAT-4CR is planned to be replaced by GSAT-31, which was launched on February 6, 2019.


INSAT-4CR was constructed by ISRO, and is based around the I-2K satellite bus.[2] A 2,168-kilogram (4,780 lb) spacecraft, it is equipped with twelve Ku band transponders operating at a frequency of 36 MHz, with 140 Watt travelling wave tube amplifiers. The satellite has an effective isotropic radiated power of 51.5 dBW. An additional Ku band signal is used as a beacon for tracking.

INSAT-4CR operated in a geostationary orbit at a longitudes of 74° East and 48° East, providing communications to India.[3] Broadcasting capacity on INSAT-4CR was allocated to Airtel Digital TV and Sun Direct DTH. At launch, the satellite was carrying 1,218 kilograms (2,685 lb) of fuel,[2] for raising itself into geostationary orbit, and subsequently operating there for a planned twelve years.[4] Increased expenditure of fuel reaching geostationary orbit, due to launch underperformance, may have resulted in a loss of up to five years of operational life.[5]


INSAT-4CR was launched on 2 September 2007 by the fifth flight of the Geosynchronous Satellite Launch Vehicle, GSLV-F04. The launch occurred at 12:51 UTC on 2 September 2007.[6] The third stage of the carrier rocket underperformed, resulting in the satellite being placed into a lower than planned orbit.

As a result of the underperformance during its launch, INSAT-4CR had to expend maneuvering and station keeping propellant to raise its orbit by more than had originally been planned. It was subsequently reported by Indian news agencies that ISRO had lost track of the satellite's orbit, and could not locate the spacecraft until NASA identified it several days later, however, ISRO denied these claims.[5][7] As a result of these failures, the operational lifetime of the satellite was reportedly decreased by up to five years.

End of life and replacement[edit]

Towards the end of its service life INSAT-4CR was relocated from 74°E[8] to 48°E slot on 10 February 2017[9] where it stayed until being retired and placed into graveyard orbit on 24 November 2020.[10] Services of INSAT-4CR were handed over to GSAT-31.


  1. ^ a b c d e McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved 3 May 2018.
  2. ^ a b Krebs, Gunter. "Insat 4C, 4CR". Gunter's Space Page. Retrieved 29 November 2011.
  3. ^ "INSAT 4CR". The Satellite Encyclopedia. Retrieved 29 November 2011.
  4. ^ "INSAT-4CR". ISRO. Archived from the original on 18 August 2013. Retrieved 29 November 2011.
  5. ^ a b Ram, Arun (15 December 2007). "Isro satellite 'disappears', loses five years of life". DNA. Retrieved 29 November 2011.
  6. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 29 November 2011.
  7. ^ "ISRO refutes INSAT-4CR 'disappearance' story". Hindustan Times. Archived from the original on 5 June 2011. Retrieved 29 November 2011.
  8. ^ "Historical satellite position data for INSAT-4CR for the month of January 2017". www.satellite-calculations.com. Archived from the original on 21 March 2021. Retrieved 21 March 2021.
  9. ^ "Historical satellite position data for INSAT-4CR for the month of February 2017". www.satellite-calculations.com. Archived from the original on 21 March 2021. Retrieved 21 March 2021.
  10. ^ "Historical satellite position data for INSAT-4CR for the month of November 2020". www.satellite-calculations.com. Archived from the original on 21 March 2021. Retrieved 21 March 2021.