IRS-1B

IRS-1B

Names	Indian Remote Sensing satellite-1B
Mission type	Earth observation
Operator	ISRO
COSPAR ID	1991-061A
SATCAT no.	21688
Website	https://www.isro.gov.in/
Mission duration	3 years (planned) 10 years (achieved)
Spacecraft properties
Spacecraft	IRS-1B
Bus	IRS-1
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
Power	600 watts
Start of mission
Launch date	29 August 1991, 06:48:43 UTC
Rocket	Vostok-2M s/n I15000-079
Launch site	Baikonur Cosmodrome, Site 31
Contractor	OKB-1
Entered service	November 1991 [1]
End of mission
Deactivated	1 July 2001 [1]
Orbital parameters
Reference system	Geocentric orbit[2]
Regime	Sun-synchronous orbit
Perigee altitude	859 km (534 mi)
Apogee altitude	915 km (569 mi)
Inclination	99.2°
Period	102.7 minutes
Instruments
Linear Imaging Self-Scanning Sensor-1 (LISS-1) Linear Imaging Self-Scanning Sensor-2 (LISS-2)
Earth observation satellites series ← 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]

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]

• Indian Remote Sensing

• ISRO IRS-1B link