The satellite will be in geo-stationary orbit, always looking over the same region

Imagine an eye far up in the sky that is constantly trained on the country and alerts authorities 36,000 km below of trouble spots, natural disasters, floods and forest fires within, say, five minutes of the event. More importantly it will also keep a watch over our sensitive borders.

The design for one such special ‘eye’ — called the Geo-Imaging Satellite or GISAT — is taking shape at the Space Applications Centre, Ahmedabad. With a recent approval and Rs. 50-crore allocation this financial year for preliminary work, GISAT should be a reality in a couple of years. The sub-1,000-kg satellite will be put in space by a PSLV rocket.

Real time imagery

Previous remote-sensing satellites sent up by the Indian Space Research Organisation also do the same job. However, they go over from pole to pole at a distance of 600-900 km from the ground, view a particular area for barely ten minutes and do not visit the same place for the next one, three or five days. GISAT, on the other hand, will be fixed in a geo-stationary orbit, always looking over the same region and synchronised to the Earth's 24-hour rotation.

A 2012-13 Budget grants document for the Department of Space describes GISAT as a “multi-spectral, multi-resolution advanced remote sensing satellite.” Its nearly real-time imagery can speed up authorities’ response to calamities and troubles to almost immediately, Mr. Tapan Misra, Deputy Director at SAC’s Microwave Remote Sensors Area, told The Hindu.

A marvel

Its electronically steerable camera can ‘see’ as small as a 60-metre area from its height of 36,000 km. It will be a marvel up there compared to what ISRO’s low-flying Earth observation satellites can do with their fine resolutions of 2 m, 1m and even less than one metre, Mr. Misra, who was here for the ISRO-CII-sponsored conference, World Space Biz 2012, said.

“A single early-warning satellite, giving you constant, complete coverage of the country, is unique,” according to Dr. V.Jayaraman, former Director at ISRO’s Hyderabad-based National Remote Sensing Centre. And a world first, he said.

It will be equivalent to putting a Cartosat — another of ISRO’s advanced ‘eyes’ but in the lower sky — at long distance.

It would complement the advanced meteorology and remote-sensing satellite, Insat-3D, due to be launched in December this year, said Dr. Jayaraman, who was earlier Director, Earth Observation, ISRO.

GISAT, Mr. Misra said, will be built on ISRO’s technologies that went into Cartosat and Radar Imaging Satellite (RISAT-1) — “both of which were big technology leaps for the country.”

More In: National | News