INSAT-4B was an Indian

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...

which forms part of the

Indian National Satellite System The Indian National Satellite System or INSAT, is a series of multipurpose geostationary satellites launched by the ISRO, Indian Space Research Organisation (ISRO) to satisfy telecommunications, broadcasting, meteorology, and search and rescu ...

. Launched in 2007, it was placed in

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular orbit, circular geosynchronous or ...

at a longitude of 93.48° East. Built by the

Indian Space Research Organisation The Indian Space Research Organisation (ISRO ) is India's national List of government space agencies, space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), ...

, INSAT-4B is based upon the I-3K

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are less customized than specially-produced satelli ...

. It had a mass at launch of , with a dry mass of and was expected to operate for twelve years. Two solar arrays power the satellite, while its communications payload consists of twelve C and twelve transponders.

Arianespace Arianespace SA is a French company founded in March 1980 as the world's first commercial launch service provider. It operates two launch vehicles: Vega C, a Small-lift launch vehicle, small-lift rocket, and Ariane 6, a Medium-lift launch vehicl ...

was contracted to launch INSAT-4B using an

Ariane 5 ECA Ariane 5 is a retired European Heavy-lift launch vehicle, heavy-lift space launch vehicle operated by Arianespace for the European Space Agency (ESA). It was launched from the Guiana Space Centre (CSG) in French Guiana. It was used to deliver p ...

carrier rocket. The launch occurred on 11 March 2007 at 22:03 UTC, from

ELA-3 ELA-3 () is a launch complex at the Guiana Space Centre in French Guiana. The complex was first used in June 1996 in support of the now retired Ariane 5 Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespac ...

at Kourou. The Skynet 5A military communications satellite for the British

Ministry of Defence A ministry of defence or defense (see American and British English spelling differences#-ce.2C -se, spelling differences), also known as a department of defence or defense, is the part of a government responsible for matters of defence and Mi ...

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. It received the International Designator 2007-007A and

Satellite Catalog Number The Satellite Catalog Number (SATCAT), also known as NORAD Catalog Number, NORAD ID, USSPACECOM object number, is a sequential nine-digit number assigned by the United States Space Command (USSPACECOM), and previously the North American Aerospac ...

30793. As of 11 November 2013, it is in an orbit with a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

of , an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

of ,

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 0.07 degrees and an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 23.93 hours.

Partial power failure

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. 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.

Relocation

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. On 20 August 2019, altitude of INSAT-4B was raised and it was relocated to new 83°E slot on 12 October 2019. On 15 February 2020, altitude of INSAT-4B was lowered and it was relocated to new 85.5°E slot on 20 February 2020.

Decommissioning

Towards the end of its life INSAT-4B was placed in

Graveyard orbit A graveyard orbit, also called a junk orbit or disposal orbit, is an Orbit (physics), orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellit ...

under post mission disposal procedure and subsequently decommissioned on 24 January 2022, in accordance with the space debris mitigation guidelines recommended by UN and the Inter Agency Space Debris Coordination Committee (IADC).

References

{{Orbital launches in 2007 Spacecraft launched in 2007 INSAT satellites 2007 in India Spacecraft decommissioned in 2022