Remembering IRS-1B which was launched exactly 25 years back

Aug 29, 2016

IRS-1B, the second of the series of indigenously developed remote sensing satellites of India, was successfully launched into a polar sun-synchronous orbit on August 29, 1991 from the Soviet Cosmodrome at Baikonur. It carried a trio of Linear Imaging Self-Scanning (LISS) remote sensing instruments working in four spectral bands: 0.45-0.52 μm, 0.52-0.59 μm, 0.62-0.68 μm, and 0.77-0.86 μm. The 38.5 kg LISS-I images a swath of 148 km with a resolution of 72.5 mtr while the 80.5 kg LISS-IIA and LISS-IIB exhibited a narrower field-of-view (74 km swath) but were aligned to provide a composite 145 km swath with a 3 km overlap and a resolution of 36.25 mtr.

IRS-1B had improved features compared to IRS-1A like gyro referencing for better orientation sensing, time tagged commanding facility for more flexibility in camera operation and line count information for better data product generation.

IRS-1B, similar to IRS-1A with improved performance provided regular data to user community. The data from the satellite was used for various applications in the areas of integrated mission for sustainable development, agriculture, forestry, flood mapping, wasteland mapping, land use/land cover mapping, snow melts and run-off studies, urban sprawl studies, wheat production estimation, locating water source etc.

IRS-1B served for 12 years and 4 months and the Mission was completed on December 20, 2003. This satellite gave a confidence in the Indian Remote Sensing satellites and gave continued support to the Indian users, and slowly shifted the users from Landsat to IRS-1B.

Data sets of three seasons (Rabi, Kharif  and Summer) have been archived as per the archival policy of ISRO. 64,939 LISS I scenes and 2,59,756 LISS II scenes have been archived during 1991 to 2001. 6,126 products of LISS-I data and 41,640 products of LISS-II data of IRS-1B have been disseminated to the various users earning a revenue of 14.5 Crores.

Even today, archived data is being used by academia for time series studies and these historical data are very much useful for legal studies which is new emerging applications.