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From Wikipedia, the free encyclopedia

NamesIndian Remote Sensing satellite-1B
Mission typeEarth observation
COSPAR ID1991-061A
SATCAT no.21688
Mission duration3 years (planned)
10 years (achieved)
Spacecraft properties
ManufacturerIndian Space Research Organisation
Launch mass975 kg (2,150 lb)
Dry mass895 kg (1,973 lb)
Dimensions1.56 m x 1.66 m x 1.10 m
Power600 watts
Start of mission
Launch date29 August 1991,
06:48:43 UTC
RocketVostok-2M s/n I15000-079
Launch siteBaikonur Cosmodrome, Site 31
Entered serviceNovember 1991 [1]
End of mission
Deactivated1 July 2001 [1]
Orbital parameters
Reference systemGeocentric orbit [2]
RegimeSun-synchronous orbit
Perigee altitude859 km (534 mi)
Apogee altitude915 km (569 mi)
Period102.7 minutes
Linear Imaging Self-Scanning Sensor-1 (LISS-1)
Linear Imaging Self-Scanning Sensor-2 (LISS-2)
← IRS-1A
IRS-1E →

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).[3]


IRS-1B was the second remote sensing mission to provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.[4]

Satellite description

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.[3]

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.[4]


IRS-1B carried two solid state push broom scanner Linear Imaging Self-Scanning Sensor (LISS):

  • LISS-1 (72 m (236 ft) each band ground resolution)
  • LlSS-2 (36 m (118 ft) each band ground resolution) [5]

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.[4]


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.[2]

IRS-1B successfully completed its mission on 1 July 2001, after operating for 10 years.[1]

See also


  1. ^ a b c "IRS-1B". World Meteorological Organization. 28 July 2015. Retrieved 12 May 2021.
  2. ^ a b "Trajectory: IRS-1B 1991-061A". NASA. 27 April 2021. Retrieved 12 May 2021. This article incorporates text from this source, which is in the public domain.
  3. ^ a b "IRS-1B". ISRO. 2008. Archived from the original on 20 March 2011. Retrieved 3 May 2020.
  4. ^ a b c "Display: IRS-1B 1991-061A". NASA. 27 April 2021. Retrieved 12 May 2021. This article incorporates text from this source, which is in the public domain.
  5. ^ "IRS (Indian Remote Sensing Satellites)". ESA Earth Observation Portal. Retrieved 12 May 2021.

External links

This page was last edited on 12 May 2021, at 22:00
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