With a price tag of Rs 250 crore Cartosat-1 is the most expensive among the satellites built so far by the Indian Space Research Organisation (ISRO). The high cost is due to the highly sophisticated instruments that will be crammed into the satellite.

"Cartosat will give more information to the military than what it is getting from existing Indian Remote Sensing (IRS) satellites," an ISRO official told newsmen.

The official was responding to recent remarks by Defence Minister George Fernandes during an interaction with reporters that IRS satellites could not detect troop movements in Kargil and that India may have to use data from foreign satellites.

Although ISRO says that Cartosat-1 is not a spy satellitein the true sense and that it is intended for cartographic applications by town planners, its scientists admit that the high-resolution, stereoscopic images obtained by the satellite will be of great use to the armed forces.

India is one of a handful of countries with highly successful remote sensing progrmames benefiting from a constellation of four IRS satellites. But even the best of these satellites cannot identify objects on the ground less than five metres in size.

On the other hand, Cartosat-1 carrying two panchromatic, or black and white, cameras will provide better than 2.5-metre spatial resolution with a steerable swatch of 30 kilometers. Resolution is a measure of imagery sharpness and ground features as small as a beach umbrella can be distinguished in Cartosat imagery.

The cameras provide stereo pairs of images needed for generation of digital terrain models, ISRO scientists said. The spacecraft also will carry a solid-state recorder for storing data that will be downloaded at a groundstation near Hyderabad. The polar-orbiting satellite will revisit the same spots every five days, according to ISRO.

The military, according to Defence Research Development Organisation (DRDO) sources, is also interested in using satellites as platforms for electronic warfare, jamming of radar and other surveillance equipment.

They said DRDO had also proposed to the government an ambitious plan for space-based surveillance, reconnaissance and intelligence based on a reusable hypersonic test vehicle.