India's Department of Posts has issued four postage stamps in the denomination of Rs.3/- commemorating the achievements under the Indian space programme. Of these, two stamps are on OCEANSAT-1 and INSAT-3B satellites that represent the country's latest achievements in satellite technology.
IRS-1D carries a combination of three cameras: i) a Panchromatic camera (PAN) with a spatial resolution of 5.8 m, ii) Linear Imaging Self Scanner (LISS-III) operating in four spectral bands with spatial resolution of 23.5 m in visible and near infrared bands and 70.5 m in short wave infrared band and iii) a Wide Field Sensor (WIFS) with a ground resolution of 188 m.
During the last three years, these cameras have been operated more than 9700 times during the satellite's 15,700 orbits around the earth. Availability of high resolution data from IRS-1D and its predecessor IRS-1C have enabled newer remote sensing applications to be taken up, especially, in the areas of urban sprawl, infrastructure planning and other large-scale thematic mapping.
Besides National Remote Sensing Agency, Hyderabad, several ground stations in North America (Norman in Oklahoma and Fairbanks in Alaska), Germany (Neustrelitz), Dubai, Equador, Abu Dabhi Saudi Arabia Japan, South Koera, Australia, Taiwan and Thailand receive data from IRS satellites under commercial agreements.
Brazil, Argentina, Gabon and Malaysia, are also expected to receive the IRS data in the near future. India today operates a constellation of five remote sensing satellites, IRS-1B, IRS-1C, IRS-1D, IRS-P3 and IRS-P4 (OCEANSAT).
It may be recalled that, 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 (ISTRAC) executed meticulously planned orbit manoeuvres to successfully put IRS-1D into a functional sun-synchronous orbit of 737 km perigee and 821 km apogee.
The scientists also ensured that the propellant on board the satellite was used optimally while carrying out the orbital manoeuvres to assure the minimum designed life of three years for the satellite mission. It is in this context that the completion of three years of IRS-1D assumes significance.
The launch of IRS-1D in September 1997, assumed great significance, since for the first time, India launched an operational satellite of the IRS-1D class using its own launch vehicle, PSLV.
Subsequently IRS-P4 (OCEANSAT) was launched by PSLV along with a Korean and German satellites on May 26, 1999. India has planned to launch the follow-on satellites, RESOURCESAT (IRS-P6) and CARTOSAT-1 (IRS-P5) in the coming years. Another satellite CARTOSAT-2 mission has also been approved.