In the period since 2013, seven navigation spacecraft and a few communication satellites dominated the domestic space scene, with the exception of the Indo-French SARAL and the weather satellite INSAT-3D of 2013.
About the long absence of EOs on their launch schedule, ISRO Chairman A.S. Kiran Kumar said, “The next four or five launches will be EO-based satellites. In the next one year, there will be three more in the Cartosat-2 series and one of them will be for civil use. Then you have Scatsat-1, Resourcesat-2A and Oceansat-3 [on the PSLV], Insat-3DR on the GSLV around August and others.” GISAT, a geo-imaging spacecraft of very high resolution and a higher orbit, is slated for 2018.
The upcoming EO (or remote sensing) satellites would be thee to four times more efficient than the older ones, providing sharper images of larger areas from about 600 km in space and repeat the view faster. They would provide far more data of ground situations than the older ones, as they would re-visit a location more frequently than before.
This was possible with the use of high-speed detection electronics components such as time delay integration devices, which would help to do continuous imaging of land areas. This was required for the country’s crop forecasting and monitoring activities that need frequent observation and sharp images.
“We are trying to continuously improve spatial [sharpness] and temporal [repetitive] features of the next EOsats so that the various ongoing application activities get better inputs,” Mr. Kiran Kumar, who is Secretary, Department of Space, told The Hindu.
“We have defined the next generation series. They will all be brought in at appropriate times and will maintain continuity of data sets. Today we are talking of going up to 0.25 metres in resolution” on an upcoming Cartosat-2 spacecraft.
Functionally, he said there was no gap in remote sensing data for the country.
“The primary reason is our launch capacity. We wanted to quickly complete the navigation constellation [IRNSS] on priority. If you had put those satellites too far apart, the completion of the constellation would have got delayed beyond its useful life.”