INDIA: TECHNOLOGICAL ACHIEVEMENTS IN SPACE
Vast is the range of spin-off benefits derived from the advancement of space technology in India. Down to earth benefits are available in such areas as mapping the natural resources through remote sensing, telecommunication, television and weather forecasting. Remote sensing date obtained from satellite-based sensors has found numerous applications in the management of natural resources. Satellite data have led to a revised inventory and mapping of land use and land cover for the whole of India. Wasteland data are now available for all the districts of the country. Land degradation studies near development areas have led to timely corrective action. And land reclamation and urban land use are better monitored from space. Satellite data have also led to the periodical updating of the country’s forest cover, evaluating the extent of deforestation and afforestation.
Satellites al so monitor the erosion of river banks, coastal erosion and the destruction of mangroves. For instance, the decline in the area of mangroves aggravated the devastation caused by the Orissa super cyclone in 1999. Detection of underground water for drinking purposes has been a success story of the country’s satellite application efforts. Ground water potential zone maps have been prepared on the basis of satellite data for most of the districts in the country. Biodiversity studies have been conducted on the basis of satélite data in the Western Ghats, Western Himalayas and the North-Eastern Region. Monitoring of snow in the Himalayas during summer months has led to an accurate forecast of snowmelt flow from the Sutlej river basin into the Bhakra reservoir.
The Indian space scientists are not far behind their counterparts in the developed countries and they have contributed a lot to the indigenization of space technology. Two remarkable achievements recent times have been the launching of INSAT-3A and the second developmental flight of the GSLV. INSAT-3A, India’s advanced multipurpose satellite, was successfully launched on April 10,2003by the European rocket Ariane-5 from the From the French Guianese spaceport of Kourou in South America. INS AT-3A represents an important step in creating and augmenting infrastructure in India for space-based broadcasting communication and meteorology. INSAT-3A is expected to augment the present INSAT capacity for communication and broadcasting besides providing meteorological services along with INS AT-2 E and Kalpana-l.
The ISRO Chairman, Prof. K. Kasrurirangan, and the Arianespace CEO, Mr. Jean Yves Le Gall, announced the signing of launch contracts for two more payloads, the DMSAT4Aand INSAT-4B on April 14, 2003. With this in the past 22 years beginning with the launch of the APPLE experimental satellite, the European Space Consortium, Arianespace, would have launched 13 ISRO satellites. Both INSAT-4A and INSAT-4B will weigh around 3200kg and are dedicated telecom satellites with 12 ku band and 12 C-band transponders.
INSAT-3A will greatly augment the country’s own satellite-based communication capacity, something that it badly requires following the expansion in the telecom and television sectors coupled with the indifferent functioning of the satellites of the INSAT-2 series. This apart, the sophisticated metrological instruments aboard the satellite, which include a very high-resolution radiometer, a charge-coupled device camera and
a data relay transponder, are expected to make a significant difference in improving weather forecasting in the country. At almost3000kg, INSAT- 3A is not only the heaviest satellite, but also the most expensive one developed by ISRO.
The next satellite in the series (INSAT-3D) will be totally devoted to meteorology; this is important since we have yet to have a comprehensive state-of-the-art weather forecasting technique. The nation can be proud of the fact that our scientists are indigenously designing and fabricating our own satellites, represented by the INSAT-2 series. Having demonstrated that ISRO can design and manufacture satellites, it is yet to develop the cryogenic technology that would enable the development of a fully indigenized geostationary satellite launch vehicle. Despite some claims of experimental success, the development of cryogenic engines might take a few more years. Presently, we are using Russian-made cryogenic engines in our Satellites.
INS AT satellites have enabled a vast expansion in the television service with over 1,079 TV transmitters linked through INSAT. The INSAT television network provides access to over 85 per cent of India’s population. INSAT-2C enables Indian television out reach beyond Indian boundaries catering to the population of South East Asia to Middle East. Educational television through INSAT has been introduced both a t the university level in the national network and at the primary school level in several States including Andhra Pradesh, Orissa, Maharashtra, Gujarat and Uttar Pradesh. A pilot project for demonstration of satellite-based developmental communication and training has been taken up in Jhabua district of Madhya Pradesh. The project is being expanded to 1,000 more villages including the adjoining districts.
India has made a big breakthrough on May 8,2003with the successful testing of the second experimental flight of the GSLV from the Satish Dhawan Space Centre at Sriharikota. We could successfully place a satellite in the challenging geosynchronous transfer orbit. The “textbook liftoff” has made GSLV a perfect operational vehicle and the success of the crucial cryogenic third stage goes to show mat our scientists are leaving nothing to chance.
The first successful GSLV flight was on April18, 2001, when the GSLV-Dl placed a 1540-kg satellite GSAT-1, in a geosynchronous transfer orbit (GTO). From the GTTO, satellites are lifted to their allotted slot by firing the boosters on board the satellites. In fact, the first flight was not completely successful; there was an under-performance. The launch was smooth and the rockets strap-ons and first two stages performed flawlessly. But the Russian made cryogenic third stage, itself making its flight, recorded a shortfall. The satellite launched by the vehicle over consumed die fuel onboard and did not consequently reach its intended slot in space.
The second GSLV-D2 launched on May 8, 2003 carried a satellite weighing almost 30 percent more—1,800 kg. But with the present class of GSLV, ISRO will not be able to launch its INSAT class of satellites, which are almost twice as heavy.
ISRO achieved a 30 per cent gain in payload weight over the last launch through its innovations. In fact, this is the heaviest satellite launched in India. On May 8, 2003, the cryogenic third stage performed to specification, facilitating the parking of its 1,800- satellite in GTO at ”the right height, the right speed and the right direction.” There is great relief in the top echelons of ISRO over the latest GSLV’s performance. They have reached the success point going through several hurdles that included technology denials. The GSLV-D2 was the 17th satellite launch rocket to be tested by the ISRO and also the most technologically challenging programme undertaken by it.
Supported by a government with a great vision, ISRO and its scientists have ambitious programmes to fulfill in the years ahead. We are, in fact even contemplating a mission to the moon. In the years ahead, our space exploration is bound to offer a vast gamut of benefits to the people of India.