IRS-1B

IRS-1B

Names	Indian Remote Sensing satellite-1B
Mission type	Earth observation
Operator	ISRO
COSPAR ID	1991-061A
SATCATno.	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	600watts
Start of mission
Launch date	29 August 1991, 06:48:43UTC
Rocket	Vostok-2Ms/n I15000-079
Launch site	Baikonur Cosmodrome,Site 31
Contractor	OKB-1
Entered service	November 1991
End of mission
Deactivated	1 July 2001
Orbital parameters
Reference system	Geocentric orbit
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-1B,Indian Remote Sensing satellite-1B, the second of the series of indigenous state-of-art remote sensing satellites, was successfully launched into a polarSun-synchronous orbiton 29 August 1991 from theSovietCosmodrome atBaikonur.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 insatellite imagery.It was a successor to theremote sensingmissionIRS-1A,both undertaken by theIndian Space Research Organisation(ISRO).

History

IRS-1B was the secondremote sensing missionto provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.

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.

The satellite was a box-shaped 1.56 m x 1.66 m x 1.10 metres bus with two Sun-trackingsolar panelsof 8.5 square metres each. Twonickel-cadmium batteriesprovided power during eclipses. Thethree-axis stabilisedSun-synchronoussatellite 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.

Instruments

IRS-1B carried two solid statepush broom scannerLinear 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)

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 onS-bandat 5.2Mbpsand from the LISS-2 at 10.4 Mbps to theground stationatShadnagar,India.The satellite was controlled fromBangalore,India.

Mission

IRS-1B was operated in aSun-synchronous orbit.On 29 August 1991, it had aperigeeof 859 km (534 mi), anapogeeof 915 km (569 mi), aninclinationof 99.2°, and anorbital periodof 102.7 minutes.

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

See also

• Indian Remote Sensing

External links

• ISRO IRS-1B link