Monday, December 19, 2016


ISRO’s latest satellite. INSAT-4A communication satellite, was successfully launched on December 22,2005 by the European Ariane-5 G launched vehicle of Arianespace, with 12 high power kuband transponders. INSAT-4A is the first satellite to meet the requirement of Direct-to-Home (DTH) television service apart from carrying 12 C-band transponders to augment the INSAT capacity for communication and TV services. Weighing 3080 kg at lift-off, INSAT-4A is the heaviest satellite of ISRO so far.
The 169th flight of Araine (Ariane 5G) with ISRO’s 3080 kg INSAT-4A and the co-passenger, meteorological satellite, MSG-2 of the European EUMENTAST, lifted off at 4:8 am Indian Standard Time (IST) form Kourou, French Guyana About 30 minutes after lift-off, INSAT-4A was placed in the Geosynchronous Transfer Orbit (GTO) in 3-axis stabilized mode. INSAT-4A is now orbiting the earth with perigee (nearest point to earth) of 622 km and an apogee (farthest point to earth) of 36152 km and an inclination of 4.02 deg with respect to the equator. The orbital period is about 10 hours 46 minutes.

Successful Launch
The Master Control Facility (MCF) at Hassan in Karnataka acquired the firs signal from INSAT-4A. The initial checks on the satellite indicated normal health of the satellite. MCF subsequently issued commands to the satellite to make the earth-viewing face to orient towards earth. The calibration of the gyros on board the satellite was also carried out. INSAT-4A is being tracked, monitored and controlled from MCF. During the initial phase of INSAT-4A operations, MCF also utilizes INMARSAT Organization’s Telemetry, Tracking and Command (TTC) ground stations at Beijing (China), Fucino (Italy) and Lake Cowichan (Canada). The Indian Space Research Organisation (ISRO) Telemetry, Tracking and Command Network (15 TRAC) ground station at Biak in Indonesia is also monitoring the satellite. The satellite’s orbit is being precisely monitoring the satellite. The Satellite’s orbit is being precisely determined by continuous ranging from the participating ground determined by continuous ranging from the participating ground stations. INSAT-4A has maneuvered to its final geostationary orbit, which is about 26,000 km. above the equator, by firing its 440 Newton Liquid Apogee Motor (LAM). When the satellite reaches near geosynchronous orbit, deployment of its solar panels and the two antennas will be carried out and the satellite put in its final –axis established mode. This will be followed by trim maneuvers to take satellite to its designated orbital slot. INSAT-4A positioned at 83 degree East longitude along with INSAT-2E and INSAT-3B.
INSAT-4A measures 15-16 meter when its solar arrays are fully deployed in orbit. The spacecraft propulsion system employs a 440 N Liquid Apogee Motor with 1500 kg of MON-3 (Mixed Oxides of Nitrogen) and MMH (Mono Methyl Hydrazine) to take the satellite from GTO and its final geosynchronous orbit. The satellite will be 3-axis body stabilized in orbit using sensors, momentum and reaction wheels, magnetic torques and eight 10 Newton and eight 22 Newton Reaction Control Thrusters. The satellite has two solar arrays together generating 5,550 watt of electrical power backed up by three 70 Ah Nickel Hydrogen Batteries. The satellite has two deployable antennas and one fixed antenna for various transmit and receive functions.
With ISRO Satellite Centre (SAC), Bangalore, as the lead centre, INSAT-4A was realized with major contributions from Space Applications Centre (SAC), Ahmedabad, Liquid Propulsion System Centre (LPSC) at Valiamala and Bangalore, Vikram Sarabhai Space Centre (VSSC) and ISRO Inertial System Unit (IISU), Thriuvananthapuram. Besides, several industries in both public and private sectors have contributed to the realization of INSAT-4A. MCF is responsible for initial phase and in-orbit operation of all geostationary satellites of ISRO. 

New Generation of Communication

The launch of the Indian Space Research Origination’s INSAT-4A telecommunications satellite inaugurates a new generation of domestic communication spacecraft. INSAT-4A will be used for Indian domestic governmental a commercial telecommunications. Its 12 Ku-Band transponders have already been sold to direct-broadcast television companies serving India, an illustration of the surgeon demand for satellite television in the subcontinent. The satellite also carried 12 C-bands transponders. It is a demand that several commercial satellite-fleet operators would like to serve. But India has a policy of obliging direct-broadcast satellite television companies to use India satellites unless those satellites are full. The Indian Space Research Organization plans three more INSAT-4 A satellites for launch by the end of 2008.
After the launch, ISRO chairman Madhavan Nair stated that the satellite ”will revolutionize” direct-to-Home (DTH) broadcasting in the country.
He said that launch is a milestone. “India spreads across 3,000 km (1875 miles) and to reach each and every village, satellite technology is the only possible way”. Mr. Nair hailed the spacecraft as the “most advanced, heaviest and powerful satellite” built by ISRO so far.
This is the first satellite in the INST-4 series. Although ISRO have its own launch vehicle, it does not have the technology to launch three-tone satellites. The organization had faced US sanction after India carried but a series of nuclear test in 1998. The sanctions have since been removed on all except three organizations attached to ISRO, which continue to face the restrictions. The 12 transponders on INSAT-4A have already been booked by Tata Sky to provide DTH services in India. Tata Sky proposes to provide 150 channels to its transponders provided by Indian satellites will increase to 150. Apart from Tata Sky, several other Indian players like Anil Ambani’s company and the Sun TV group are waiting for space on INSAT series of satellites to start their DTH service that have been announced earlier. 
The satellite, which has design life of 12 years, itself, cost Rs. 230 crore, while the launch and insurance added up to another Rs.300 crore. The Ariane rocket also put into space MSG-2, a weather satellite for the European Organization Eumestat. ISRO is a long-standing client of Arianespace and used the agency way back in 1981 to launch its experimental satellite Apple. INSAT-4A is the 12th satellite to be launched by Ariane and ISRO plans to use Arianespace to launch INSAT-4B as well.
The launch of the Metosat 9 stellite called MSG-2 before launch for Europe’s meteorological satellite organization, the 18 nation Eumatsat, will give Europe a backup satellites to join its twin, Metosat 8, which is already operational. These two satellites are the first of the four Metosat Second Generation Spacecraft, which provide imagery from 12 spectral channels every 15 minutes. The four Metosat Second Generation Satellites will provide climate and weather data through 2018.The total program is valued at 2 billion euros ($2.86 billion), including the production, launch and operations of the four satellites.
The MSG-2 platform is a spinstabilised spacecraft developed by Alcatel Alenia Space to provide high resolution images of the earth’s weather activity for the European Meteorological Satellite Organisation (EUMETSAT). The 2,084 kg satellite also will measure the planets radiation balance for information on climate change.
Indian National Satellite (INSAT) System
The INSAT series consists of --- INSAT-2E,INSAT 3A,3B,3C,3E, KALAPANA-I, GSAT-2 AND EDUSAT. The system providers over 140 communications transponders working in the C, extended C and K bands besides metrological instruments.
The Indian Remote Sensing (IRS) Satellite System is the world’s largest constellation of civilian remote sensing satellites providing series at the national and global level. Our forthcoming satellites are OCEANSAT-2,RISAT-1 SERRIES 4B,4D,4E and Scientific Satellites ASTROSTAT and Chandrayan-I.


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