|Names||Indian Remote Sensing satellite-1B|
|Mission type||Earth observation|
|Mission duration||3 years (planned)|
10 years (achieved)
|Manufacturer||Indian Space Research Organisation|
|Launch mass||975 kg (2,150 lb)|
|Dry mass||895 kg (1,973 lb)|
|Dimensions||1.56 m x 1.66 m x 1.10 m|
|Start of mission|
|Launch date||29 August 1991,|
|Rocket||Vostok-2M s/n I15000-079|
|Launch site||Baikonur Cosmodrome, Site 31|
|Entered service||November 1991 |
|End of mission|
|Deactivated||1 July 2001 |
|Reference system||Geocentric orbit|
|Perigee altitude||859 km (534 mi)|
|Apogee altitude||915 km (569 mi)|
|Linear Imaging Self-Scanning Sensor-1 (LISS-1)|
Linear Imaging Self-Scanning Sensor-2 (LISS-2)
IRS-1B, Indian Remote Sensing satellite-1B, the second of the series of indigenous state-of-art remote sensing satellites, was successfully launched into a polar Sun-synchronous orbit on 29 August 1991 from the Soviet Cosmodrome at Baikonur. IRS-1B carries two sensors, LISS-1 and LISS-2, with resolutions of 72 m (236 ft) and 36 m (118 ft) respectively with a swath width of about 140 km (87 mi) during each pass over the country. It was a part-operational, part-experimental mission to develop Indian expertise in satellite imagery. It was a successor to the remote sensing mission IRS-1A, both undertaken by the Indian Space Research Organisation (ISRO).
IRS-1B was the second remote sensing mission to provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.
Improved features compared to its predecessor (IRS-1A): gyroscope referencing for better orientation sensing, time tagged commanding facility for more flexibility in camera operation and line count information for better data product generation.
The satellite was a box-shaped 1.56 m x 1.66 m x 1.10 metres bus with two Sun-tracking solar panels of 8.5 square metres each. Two nickel-cadmium batteries provided power during eclipses. The three-axis stabilised Sun-synchronous satellite had a 0.4° pitch/roll and 0.5° yaw pointing accuracy provided by a zero-momentum reaction wheel system utilising Earth/Sun/star sensors and gyroscopes.
IRS-1B carried two solid state push broom scanner Linear Imaging Self-Scanning Sensor (LISS):
The satellite carried two LISS push broom CCD sensors operating in four spectral bands compatible with Landsat Thematic Mapper and Spot HRV data. The bands were 0.45-0.52, 0.52-0.59, 0.62-0.68, and 0.77-0.86 microns. The LISS-1 sensor had four 2048-element CCD imagers with a focal length of 162.2 cm (63.9 in) generating a resolution of 72 m (236 ft) and a 148 km (92 mi) swath width. The LISS-2 sensor had eight 2048-element CCD imagers with a focal length of 324.4 mm (12.77 in) generating a ground resolution of 36 m (118 ft) and a 74 km (46 mi) swath width. The LISS-2 imager bracketed the LISS-1 imager providing a 3 km (1.9 mi) overlap. Data from the LISS-1 were downlinked on S-band at 5.2 Mbps and from the LISS-2 at 10.4 Mbps to the ground station at Shadnagar, India. The satellite was controlled from Bangalore, India.
IRS-1B was operated in a Sun-synchronous orbit. On 29 August 1991, it had a perigee of 859 km (534 mi), an apogee of 915 km (569 mi), an inclination of 99.2°, and an orbital period of 102.7 minutes.
IRS-1B successfully completed its mission on 1 July 2001, after operating for 10 years.