The Indian Space Research Organisation is developing a microwave remote sensing satellite, RISAT, which enables observations even during night and under cloudy conditions.

The Radar Imaging Satellite, as this new satellite will be called, will be launched in 2006, from Sriharikota, on India's Polar Satellite Launch Vehicle. It will have a mission life of 5 years.

As of now, work on developing this satellite is under way at ISRO's Satellite Centre in Bangalore.

The main purpose of the RISAT is to support and augment the country's operational remote sensing programme by enhancing agricultural and disaster related applications.

RISAT will carry sophisticated radars, scanners and other scientific instruments. The RISAT is to be launched into a polar sun-synchronous orbit of 609km.

ISRO estimates the satellite will cost nearly Rs 350 crores to build. "We are adopting a new approach to building the radar antenna," says Dr P S Goel director of ISAC. "The same kind of satellite would have cost a billion dollars to build in the West.

According to him, the RISAT will give ISRO greater flexibility to map satellite images. It will also have S band transponders for resource mapping and agriculture. Some levels of data management of images, which was earlier being done from the ground, will now be done from the satellite.

ISRO will also launch CARTOSAT 1 and CARTOSAT 2, two cartographic mapping satellites, before RISAT.