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INSAT-4B is an Indian communications satellite which forms part of the Indian National Satellite System. Launched in 2007, it is operated in geostationary orbit at a longitude of 93.48° east.[3]

Mission typeCommunications
COSPAR ID2007-007A
SATCAT no.30793
Mission duration12 years
Spacecraft properties
Launch mass3,028 kilograms (6,676 lb)
Dry mass1,335 kilograms (2,943 lb)
Start of mission
Launch date11 March 2007, 22:03 (2007-03-11UTC22:03Z) UTC[1]
RocketAriane 5ECA
Launch siteKourou ELA-3
Orbital parameters
Reference systemGeocentric
Longitude93.48° E (Relocated to 111.2° E on 18 December 2017)
Semi-major axis42,163.57 kilometres (26,199.23 mi)
Perigee altitude35,776 kilometres (22,230 mi)
Apogee altitude35,809 kilometres (22,251 mi)
Inclination0.07 degrees
Period23.93 hours
Epoch11 November 2013, 22:16:22 UTC[2]

Built by the Indian Space Research Organisation, INSAT-4B is based upon the I-3K satellite bus. It had a mass at launch of 3,028 kilograms (6,676 lb), with a dry mass of 1,335 kilograms (2,943 lb) and was expected to operate for twelve years. Two solar arrays power the satellite, while its communications payload consists of twelve C and twelve Ku band transponders.[4]

Arianespace was contracted to launch INSAT-4B using an Ariane 5 ECA carrier rocket. The launch occurred on 11 March 2007 at 22:03 UTC, from ELA-3 at Kourou.[1] The Skynet 5A military communications satellite for the British Ministry of Defence was launched aboard the same rocket.

INSAT-4B was successfully inserted into geosynchronous transfer orbit, from which it raised itself into geostationary orbit using a liquid-fuelled apogee motor.[4] It received the International Designator 2007-007A and Satellite Catalog Number 30793.[5] As of 11 November 2013, it is in an orbit with a perigee of 35,776 kilometres (22,230 mi), an apogee of 35,809 kilometres (22,251 mi), inclination of 0.07 degrees and an orbital period of 23.93 hours.[2]

Partial power failureEdit

On 10 July 2010 INSAT-4B suffered a disruption in power supply from one of the two solar panels, rendering half of its transponder capacity useless. After review the cause of malfunction was found out to be electric arcing in slip ring of one of the solar panels.[6] Similar partial power supply failure also affected Eutelsat W2M now known as Afghansat 1 and caused delay in launch of GSAT-8 due to required design changes in relevant power systems of satellite bus.[7][8]


On 11 November 2017, INSAT-4B maneuvered to lower its altitude and drifted eastward to reach new slot at 111.2°E on 18 December 2017.[9]


  1. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 12 November 2013.
  2. ^ a b "INSAT 4B Satellite details 2007-007A NORAD 30793". N2YO. 11 November 2013. Retrieved 12 November 2013.
  3. ^ "UCS Satellite Database". Union of Concerned Scientists. 1 September 2013. Retrieved 12 November 2013.
  4. ^ a b Krebs, Gunter. "Insat 4A, 4B". Gunter's Space Page. Retrieved 12 November 2013.
  5. ^ McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 12 November 2013.
  6. ^ Radhakrishnan, Koppillil (2016). My Odyssey: Memoirs of the Man behind the Mangalyaan Mission. Penguin UK. p. 190. ISBN 9385990381.
  7. ^ "'India losing satellites due to failure of imported components'". 2010-07-11. Retrieved 2017-12-19.
  8. ^ "Report number 22 by Comptroller Auditor General" (PDF). Retrieved 19 December 2017.
  9. ^ "Archived TLE data from". Retrieved 19 December 2017.