INSAT-4CR
Encyclopedia
INSAT-4CR is 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 is stationed in geostationary orbit
at a lognitude of 74 degrees east, and is expected to operate for ten years, however this may have been reduced by the underperformance of the Geosynchronous Satellite Launch Vehicle
which placed it into orbit.
. A 2168 kilograms (4,779.6 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 operates in a geostationary orbit at a longitude of 74 degrees east, providing communications to India
. Broadcasting capacity on INSAT-4CR is allocated to Airtel Digital TV
and Sun Direct DTH
. At launch, the satellite was carrying 1218 kilograms (2,685.2 lb) of fuel, for raising itself into geostationary orbit, and subsequently operateing there for a planned twelve years. Increased expendature of fuel reaching geostationary orbit, due to launch underperformance, may have resulted in a loss of up to five years of operational life.
, GSLV-F04. The launch occurred at 12:51 UTC on 2 September 2007. 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 manoeuvring 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. As a result of these failures, the operational lifetime of the satellite was reportedly decreased by up to five years.
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
operated by ISRO as part of the Indian National Satellite System
Indian National Satellite System
INSAT or the Indian National Satellite System is a series of multipurpose Geo-stationary satellites launched by ISRO to satisfy the telecommunications, broadcasting, meteorology, and search and rescue operations....
. Launched in September 2007, it replaced the INSAT-4C satellite which had been lost in a launch failure the previous year. The satellite is stationed in geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
at a lognitude of 74 degrees east, and is expected to operate for ten years, however this may have been reduced by the underperformance of the Geosynchronous Satellite Launch Vehicle
Geosynchronous Satellite Launch Vehicle
The Geosynchronous Satellite Launch Vehicle is an expendable launch system operated by the Indian Space Research Organisation...
which placed it into orbit.
Spacecraft
INSAT-4CR was constructed by ISRO, and is based around the I2K satellite busSatellite bus
A satellite bus or spacecraft bus is the general model on which multiple-production satellite spacecraft are often based. The bus is the infrastructure of a spacecraft, usually providing locations for the payload .They are most commonly used for geosynchronous satellites, particularly...
. A 2168 kilograms (4,779.6 lb) spacecraft, it is equipped with twelve Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-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 operates in a geostationary orbit at a longitude of 74 degrees east, providing communications to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. Broadcasting capacity on INSAT-4CR is allocated to Airtel Digital TV
Airtel digital TV
Airtel digital TV is an Indian direct broadcast satellite service provider owned and operated by Bharti Airtel. Its satellite service, launched on 2008, transmits digital satellite television and audio to households in India. It uses MPEG-4 digital compression with DVB-S2 technology, transmitting...
and Sun Direct DTH
Sun Direct DTH
Sun Direct is an Indian direct broadcast satellite service provider. Its satellite service, launched on 2005, transmits digital satellite television and audio to households in India. Sun Direct uses MPEG-4 digital compression technology, transmitting on INSAT 4B at 93.5°E. and MEASAT-3 at 91.5°E...
. At launch, the satellite was carrying 1218 kilograms (2,685.2 lb) of fuel, for raising itself into geostationary orbit, and subsequently operateing there for a planned twelve years. Increased expendature of fuel reaching geostationary orbit, due to launch underperformance, may have resulted in a loss of up to five years of operational life.
Launch
INSAT-4CR was launched on 2 September 2007 by the fifth flight of the Geosynchronous Satellite Launch VehicleGeosynchronous Satellite Launch Vehicle
The Geosynchronous Satellite Launch Vehicle is an expendable launch system operated by the Indian Space Research Organisation...
, GSLV-F04. The launch occurred at 12:51 UTC on 2 September 2007. 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 manoeuvring 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
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
identified it several days later, however ISRO denied these claims. As a result of these failures, the operational lifetime of the satellite was reportedly decreased by up to five years.