India launched its sharpest ‘eye in the sky’ from the Satish Dhawan Space Centre on the east coast on Wednesday. Riding on ISRO’s Polar Satellite Launch Vehicle PSLV-C47 on its 49th flight, India’s 3rd-generation advanced earth imaging and mapping satellite Cartosat-3 was lofted into sun-synchronous polar orbit just over 17 minutes after launch. Cartosat-3 is the highest resolution civilian satellite put into orbit by ISRO. The PSLV-C47 used for the launch was the most powerful version of the PSLV, which used six strap-on boosters. The rocket also carried 13 nanosatellites of two US customers as part of commercial arrangement with New Space India Limited (NSIL) of India’s Department of Space. The nanosatellites were released sequentially after Cartosat-3 was inserted into its planned orbit of 509 kilometres.
So far, the Indian Space Research Organisation, ISRO, has orbited eight Cartosats since May 2005 – one Cartosat-1 and seven in the Cartosat-2 series. Data from most of them, especially the last four of theCartosat-2 series, launched in relatively quick succession in the last three years, are exclusively used by the armed forces. Weighing 1,625 kilograms, Cartosat-3 is more than double the mass of the previous eight in its class. Many new technologies have been developed and built in, such as a highly agile or flexible camera; high-speed data transmission, advanced computer system and new power electronics.
Cartosat-3 is the 9th in the Cartosat series of earth observation satellites and ushers in the third generation of high-resolution ‘optical imaging’ satellites that allow precise cartographic or mapping activities It can also be used for surveillance along our borders. Cartosat-3 offers the highest resolution of any earth observation satellite currently in orbit. With a ground resolution of 25 centimetres, it is better than that of WorldView-3, a satellite owned by US company Maxar, which had till now the best ground resolution of 31 centimetres. This means that Cartosat-3 can pick up an object of a minimum size of 25 centimetres from a height of around 500 kilometres. The last four satellites of the Cartosat-2 series – 2C, 2D, 2E and 2F – had a resolution of 65 centimetres.
Among the 13 nanosatellites is one satellite named MESHBED, whose mission objective is communication test bed, and 12 FLOCK-4P nanosatellites with mission objective of earth observation.
According to the ISRO, “The imageries from Cartosat series satellites are useful for cartographic applications, urban and rural applications, infrastructure planning, coastal land use and regulation, utility management such as monitoring road networks, water grids or distribution, creation of land use maps, among others.”
A significant feature of the Cartosat-3 mission is the close participation of private industry in the Assembly, Integration & Testing of satellites. ISRO has stated its hopes that this will pave the way for end-to-end satellite development by the private industry. Presently, the agency aims to develop 12 to 18 satellites per year; reports have stated that the successful vendors will collectively be working on 27 satellites out of the 36 or more satellites that ISRO is projecting for the next three years.
Wednesday’s success has once again demonstrated the high reliability of the PSLV rocket, which has become the workhorse of ISRO. Out of 49 launches till date, the rocket has encountered only two failures so far – its maiden developmental flight ended unsuccessful way back in 1993. In September 2017, the PSLV performed perfectly and the flight went off without any hitch, but the IRNSS-1H satellite could not be released into orbit after the PSLV-C39’s heat shield failed to open before reaching the orbit. The PSLV has also been used to launch Chandrayaan-1, India’s first mission to Moon and the Mars Orbiter Mission to Mars.
ISRO is now gearing up to send the first Indians to space from Indian soil. The first Indian crew is scheduled to be sent to a low-earth orbit before the 75th anniversary of the country’s Independence in 2022. With a chain of successes behind it, ISRO can hopefully look forward to achieving it.
Script: Biman Basu, Senior Science Commentator