The launch of two remote-sensing satellites today is part of ISRO's plans for expanding its constellation of earth-observing satellites. Twenty years ago, the Indian Space Research Organisation (ISRO) launched the country's first operational earth-observation satellite, the IRS-1A. In the years since then, ISRO has sent up 10 more remote-sensing satellites. (Six of these satellites are currently operational, including the ageing IRS-1D, which was launched more than 10 years ago with a design life of three years and is reportedly used sparingly these days.)