IRS-1A

Names	Indian Remote Sensing satellite-1A
Mission type	Earth observation
Operator	ISRO
COSPAR ID	1988-021A
SATCAT no.	18960
Website	https://www.isro.gov.in/
Mission duration	3 years (planned) 4 years (achieved)
Spacecraft properties
Spacecraft	IRS-1A
Bus	IRS-1
Manufacturer	Indian Space Research Organization
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	17 March 1988, 06:43:00 UTC
Rocket	Vostok-2M s/n L15000-79
Launch site	Baikonur Cosmodrome, Site 31
Contractor	OKB-1
Entered service	June 1988 [1]
End of mission
Deactivated	1 July 1992 [1]
Orbital parameters
Reference system	Geocentric orbit[2]
Regime	Sun-synchronous orbit
Perigee altitude	863 km (536 mi)
Apogee altitude	917 km (570 mi)
Inclination	99.01°
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 →

IRS-1A, Indian Remote Sensing satellite-1A, the first of the series of indigenous state-of-art remote sensing satellites, was successfully launched into a polar Sun-synchronous orbit on 17 March 1988 from the Soviet Cosmodrome at Baikonur. IRS-1A 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. Undertaken by the Indian Space Research Organisation (ISRO). It was a part-operational, part-experimental mission to develop Indian expertise in satellite imagery.

The availability of Landsat imagery created a lot of interest in the science community. The Hyderabad ground station started receiving Landsat data on a regular basis in 1978. The Landsat program with its design and potentials was certainly a great model and yardstick for the IRS programme. IRS-1A was the first remote sensing mission to provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.^[3] The mission's long-term objective was to develop indigenous remote sensing capability.^[4]

The satellite bus, measuring 1.56 m x 1.66 m x 1.10 metres, had the payload module attached on the top and a deployable solar panels stowed on either side. Attitude control was provided by four-momentum wheels, two magnetic torques, and a thruster system. Together, they gave an estimated accuracy of better than ± 0.10° in all three axes.^[3]

IRS-1A carried two "Linear Imaging Self-Scanning Sensor", LISS-1 and LISS-2, with a spatial resolution of 72 m (236 ft) and 36 m (118 ft) respectively.^[5] The three-axis-stabilised Sun-synchronous satellite carried LISS sensors which performed "push-broom" scanning in visible and near-infrared bands to acquire images of the Earth. Local equatorial crossing time (ECT) was fixed at around 10:30 of the morning.^[3]

IRS-1A was launched on 17 March 1988, at 06:43:00 UTC. It had a perigee of 863 km (536 mi), an apogee of 917 km (570 mi), an inclination of 99.01°, and an orbital period of 102.7 minutes.^[2]

IRS-1A was operated in a Sun-synchronous orbit. IRS-1A successfully completed its mission on 1 July 1992 after operating for 4 years.^[1]

• Indian Remote Sensing

• ISRO IRS-1A link