| IRS-1A | |
| Names List: | Indian Remote Sensing satellite-1A |
| Operator: | ISRO |
| Cospar Id: | 1988-021A |
| Satcat: | 18960 |
| Website: | https://www.isro.gov.in/ |
| Mission Duration: | 3 years (planned) 4 years (achieved) |
| Spacecraft: | IRS-1A |
| Spacecraft Bus: | IRS-1 |
| Manufacturer: | Indian Space Research Organization |
| Dimensions: | 1.56 m x 1.66 m x 1.10 m |
| Power: | 600 watts |
| Launch Date: | 17 March 1988, 06:43:00 UTC |
| Launch Rocket: | Vostok-2M s/n L15000-79 |
| Launch Site: | Baikonur Cosmodrome, Site 31 |
| Launch Contractor: | OKB-1 |
| Entered Service: | June 1988 |
| Deactivated: | 1 July 1992 |
| Orbit Reference: | Geocentric orbit |
| Orbit Regime: | Sun-synchronous orbit |
| Orbit Inclination: | 99.01° |
| Orbit Period: | 102.7 minutes |
| Apsis: | gee |
| Instruments: | Linear Imaging Self-Scanning Sensor-1 (LISS-1) Linear Imaging Self-Scanning Sensor-2 (LISS-2) |
| Programme: | Earth observation satellites series |
| Next Mission: | 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 and respectively with a swath width of about 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.[1] The mission's long-term objective was to develop indigenous remote sensing capability.[2]
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.[1]
IRS-1A carried two "Linear Imaging Self-Scanning Sensor", LISS-1 and LISS-2, with a spatial resolution of and respectively.[3] 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.[1]
IRS-1A was launched on 17 March 1988, at 06:43:00 UTC. It had a perigee of, an apogee of, an inclination of 99.01°, and an orbital period of 102.7 minutes.[4]
IRS-1A was operated in a Sun-synchronous orbit. IRS-1A successfully completed its mission on 1 July 1992 after operating for 4 years.[5]