Opinion - Editorials

Another milestone for ISRO

THE SUCCESSFUL LAUNCH of the Metsat on a Polar Satellite Launch Vehicle from the newly-named Satish Dhawan Space Centre is yet another landmark achievement for the Indian Space Research Organisation. Once the satellite with its high resolution camera is moved to its geostationary orbit, it should provide substantial additional meteorological information on South Asia and its environs. With Metsat, a satellite that will be used exclusively to generate images for meteorological analysis, the ability of the Indian Meteorological Department to successfully keep track of rapidly developing weather patterns is likely to be considerably enhanced. The absence of a weather satellite in geostationary orbit was cited as one reason why the IMD could not estimate with any degree of accuracy the path or intensity of the devastating cyclone which struck Orissa in 1999.

There are two special features of the latest ISRO launch. The first is, of course, the launch of India's first exclusive meteorological satellite. Until now, weather-related information was obtained from the ISRO satellites in the Insat series, which have all been multipurpose satellites where the main focus has been on providing communication capacity. While such multipurpose satellites made sense in the early years of ISRO's satellite programme — when the need for such services was itself debated — it appears that it is now in the organisation's interests to launch satellites devoted solely to providing communication capacity. These satellites would contain many more communications transponders, which ISRO could offer at more competitive rates to potential users than if it had to also carry a camera for meteorological purposes. The Metsat will not fetch ISRO any revenue though a stand-alone weather satellite provides priceless non-commercial information. But by separating the meteorological from the communications services, ISRO has the chance of realising the considerable commercial potential in the growing demand for communications capacity on satellites. The second unique feature of the launch that has sent up the Metsat is the adaptation of the PSLV, which is normally used to put satellites in a polar orbit, to send the 1,060 kg satellite into a geostationary transfer orbit. Launches for geostationary transfer orbits, the intermediate stage to the geostationary position when the satellite matches the Earth's rotation and is therefore at a fixed relative point in the sky, are usually conducted by a Geosynchronous Satellite Launch Vehicle. But the GSLV is more economical for heavier satellites, not for relatively lightweight ones like the Metsat. ISRO's successful adaptation of the PSLV (whose launch costs are considerably less than the GSLV) for sending the weather satellite into the geostationary transfer orbit is an indication of its ability to innovate according to the demands of the situation. The organisation's involvement in the launch of weather satellites does not end with the successful send-up of the Metsat. In a couple of years, ISRO plans to launch a two-tonne exclusive weather satellite, the Insat-3D, which will then add substantially to the IMD's information gathering capacity.

An additional advantage of having Metsat in the sky is that the IMD will no longer have to use information gathered by other satellites like Europe's Meteosat-5. While the earlier Very High Resolution Radiometers, the cameras that generate images, on the Insat satellites did not function perfectly, the improvements that have since been made make it likely that the IMD will now get the best possible information. The Metsat has an improved VHRR that will beam a stream of images from its geostationary orbit. The range of successful launches that ISRO has conducted in recent years means that it is now ready to actively solicit contracts in the satellite launch business. ISRO has already launched a couple of satellites on commercial considerations, but given its increasingly enviable record these can only be the first of many more contracts.

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