IRS-1D


IRS-1D is the seventh satellite in Indian Remote Sensing satellite series of Earth Observation satellites, built, launched and maintained by Indian Space Research Organisation. The satellite has similar capabilities as that of ISRO's IRS-1C satellite with some improvements added for better imagery particularly in thematic mapping.

Launch

The 1250 kg IRS-1D is an Indian remote sensing Sun-synchronous orbiter that was launched by a PSLV-1C rocket from Sriharikota at 04:47:00 UTC. The 44.4 metres, four-stage, 494-ton PSLV-1C is now an operational vehicle, after earlier test launches, it is the fourth launch vehicle PSLV. Orbit maneuvers may be planned to raise the perigee.
Due to a slight under performance of PSLV fourth stage, IRS-1D was injected with a velocity that was 130 m/sec less than the required 7446 m/sec. This minor shortfall in the injection velocity resulted in IRS-1D being injected into a polar orbit with an apogee of 822 km and a perigee of 301 km instead of the intended 817 km circular orbit. But, ISRO scientists, monitoring and controlling the satellite from ISRO Telemetry, Tracking and Command Network executed meticulously planned orbit manoeuvres to successfully put IRS-1D into a functional sun-synchronous orbit of 740 km perigee and 817 km apogee.

Payloads

The satellite carried following instruments onboard:
An on-board tape recorder stores data over unreachable intervals. Sensed data on Indian and foreign terrains will be sold through an American company.