India's remote sensing program was developed with the idea of applying space technologies for the benefit of humankind and the development of the country. The program involved the development of three principal capabilities. The first was to design, build and launch satellites to a Sun-synchronous orbit. The second was to establish and operate ground stations for spacecraft control, data transfer along with data processing and archival. The third was to use the data obtained for various applications on the ground.[1]
India demonstrated the ability of remote sensing for societal application by detecting coconut root-wilt disease from a helicopter mounted multispectral camera in 1970. This was followed by flying two experimental satellites, Bhaskara-1 in 1979 and Bhaskara-2 in 1981. These satellites carried optical and microwave payloads.[2]
India's remote sensing programme under the Indian Space Research Organization (ISRO) started off in 1988 with the IRS-1A, the first of the series of indigenous state-of-art operating remote sensing satellites, which was successfully launched into a polar Sun-synchronous orbit on March 17, 1988, from the Soviet Cosmodrome at Baikonur.
It has sensors like LISS-I which had a spatial resolution of 72.5m (237.9feet) with a swath of 148km (92miles) on ground. LISS-II had two separate imaging sensors, LISS-II A and LISS-II B, with spatial resolution of 36.25m (118.93feet) each and mounted on the spacecraft in such a way to provide a composite swath of 146.98km (91.33miles) on ground. These tools quickly enabled India to map, monitor and manage its natural resources at various spatial resolutions. The operational availability of data products to the user organisations further strengthened the relevance of remote sensing applications and management in the country.[3]
Following the successful demonstration flights of Bhaskara-1 and Bhaskara-2 satellites launched in 1979 and 1981, respectively, India began to develop the indigenous Indian Remote Sensing (IRS) satellite program to support the national economy in the areas of agriculture, water resources, forestry and ecology, geology, water sheds, marine fisheries and coastal management.
Towards this end, India had established the National Natural Resources Management System (NNRMS) for which the Department of Space (DOS) is the nodal agency, providing operational remote sensing data services.[4] Data from the IRS satellites is received and disseminated by several countries all over the world. With the advent of high-resolution satellites, new applications in the areas of urban sprawl, infrastructure planning and other large scale applications for mapping have been initiated.
The IRS system is the largest constellation of remote sensing satellites for civilian use in operation today in the world, with 11 operational satellites. All these are placed in polar Sun-synchronous orbit and provide data in a variety of spatial, spectral and temporal resolutions. Indian Remote Sensing Programme completed its 25 years of successful operations on March 17, 2013.
Data from Indian Remote Sensing satellites are used for various applications of resources survey and management under the National Natural Resources Management System (NNRMS). Following is the list of those applications:
The initial versions are composed of the 1 (A,B,C,D). The later versions are named based on their area of application, including OceanSat, CartoSat, ResourceSat. Some of the satellites have alternate designations based on the launch number and vehicle (P series for PSLV). From 2020, the name was changed to the generic EOS, which stands for Earth Observation Satellite.[5]
| Serial No. | Satellite | Date of Launch | Launch Vehicle | Status |
| 1 | IRS-1A | 17 March 1988 | Vostok, USSR | Mission Completed |
| 2 | IRS-1B | 29 August 1991 | Vostok, USSR | Mission Completed |
| 3 | IRS-P1 (also IE) | 20 September 1993 | PSLV-D1 | Crashed, due to launch failure of PSLV |
| 4 | IRS-P2 | 15 October 1994 | PSLV-D2 | Mission Completed |
| 5 | IRS-1C | 28 December 1995 | Molniya, Russia | Mission Completed |
| 6 | IRS-P3 | 21 March 1996 | PSLV-D3 | Mission Completed |
| 7 | IRS 1D | 29 September 1997 | PSLV-C1 | Mission Completed |
| 8 | IRS-P4 (Oceansat-1) | 27 May 1999 | PSLV-C2 | Mission Completed |
| 9 | Technology Experiment Satellite (TES) | 22 October 2001 | PSLV-C3 | Mission Completed |
| 10 | IRS P6 (Resourcesat-1) | 17 October 2003 | PSLV-C5 | Mission Completed |
| 11 | IRS P5 (Cartosat 1) | 5 May 2005 | PSLV-C6 | Mission Completed |
| 12 | IRS P7 (Cartosat 2) | 10 January 2007 | PSLV-C7 | Mission Completed |
| 13 | Cartosat 2A | 28 April 2008 | PSLV-C9 | In Service |
| 14 | IMS 1 | 28 April 2008 | PSLV-C9 | Mission Completed |
| 15 | RISAT-2 | 20 April 2009 | PSLV-C12 | In Service |
| 16 | Oceansat-2 | 23 September 2009 | PSLV-C14 | In Service |
| 17 | Cartosat-2B | 12 July 2010 | PSLV-C15 | In Service |
| 18 | Resourcesat-2 | 20 April 2011 | PSLV-C16 | In Service |
| 19 | Megha-Tropiques | 12 October 2011 | PSLV-C18 | Mission Completed |
| 20 | RISAT-1 | 26 April 2012 | PSLV-C19 | Mission Completed |
| 21 | SARAL | 25 February 2013 | PSLV-C20 | In Service |
| 22 | Cartosat-2C | 22 June 2016 | PSLV-C34 | In Service |
| 23 | ScatSat-1 | 26 September 2016 | PSLV-C35 | In Service |
| 24 | RESOURCESAT-2A | 7 December 2016 | PSLV-C36 | In Service |
| 25 | Cartosat-2D | 15 February 2017 | PSLV-C37 | In Service |
| 26 | Cartosat-2E | 23 June 2017 | PSLV-C38 | In Service |
| 27 | Cartosat-2F | 12 January 2018 | PSLV-C40 | In Service |
| 28 | RISAT-2B | 22 May 2019 | PSLV-C46 | In Service |
| 29 | Cartosat-3 | 27 November 2019 | PSLV-C47 | In Service |
| 30 | RISAT-2BR1 | 11 December 2019 | PSLV-C48 | In Service |
| 31 | EOS-1 (RISAT-2BR2) | 7 November 2020 | PSLV-C49 | In Service |
| 32 | EOS-3 (GISAT-1) | 12 August 2021 | GSLV-F10 | Crashed, due to launch failure of GSLV |
| 33 | EOS-4 (RISAT-1A) | 14 February 2022 | PSLV-C52 | In Service |
| 34 | EOS-2 (Microsat-2A) | 7 August 2022 | SSLV-D1 | Crashed, due to launch failure of SSLV |
| 35 | EOS-6 (Oceansat-3) | 26 November 2022 | PSLV-C54 | In Service |
| 36 | EOS-7 (Microsat-2B) | 10 February 2023 | SSLV-D2 | In Service |
| 37 | EOS-5 (GISAT-2) | March 2024 | GSLV Mk II | Planned |
| 38 | RISAT-1B | 2024 (TBD) | PSLV-XL | Planned |
| 39 | RISAT-2A | 2024 (TBD) | PSLV-XL | Planned |
| 40 | Cartosat-3A (EOS-08) | 2024 (TBD) | PSLV-XL | Planned |
| 41 | Cartosat-3B | 2024 (TBD) | PSLV-XL | Planned |
| 42 | Oceansat-3A | 2025 (TBD) | PSLV-XL | Planned |
| 43 | Resourcesat-3 | 2025 (TBD) | PSLV-XL | Planned |
| 44 | Resourcesat-3A | 2026 (TBD) | PSLV-XL | Planned |
| 45 | Resourcesat-3B | 2026 (TBD) | PSLV-XL | Planned |
| 46 | Resourcesat-3S | 2026 (TBD) | PSLV-XL | Planned |
| 47 | Resourcesat-3SA | 2027 (TBD) | PSLV-XL | Planned |
Data from IRS is available to its users through NRSC Data Centre and also through Bhuvan Geoportal of ISRO. NRSC data center provides data through its purchase process, while Bhuvan Geoportal provides data in free and open domain.
The capacity building programme of ISRO for IRS and other remote sensing applications is through Indian Institute of Remote Sensing (IIRS) Dehradun and UN affiliated Center of Space Science and Technology Education in Asia and the Pacific (CSSTEAP) Center located at Dehradun of Uttrakhand State in India.