National Remote Sensing Day

National Remote Sensing Day is celebrated every year on the 12th August, on the Occasion of birth anniversary of Prof. Vikram Sarabhai, A Great renowned Indian Scientist and physicist and a great innovator who established the Indian Space programme at 1969 and widely regarded as the “Father of India’s Space Programme”.

This Year, as we mark the 101th birth anniversary of Dr. Vikram Sarabhai, We as Geo-Spatial Community are excited to celebrate the National Remote Sensing Day by spreading the word of Remote Sensing and Space Science with special emphasis to its application for environment and society and spread awareness on harnessing the use of remote sensing technologies for the environment and society.

Vikram Sarabhai

Dr. Sarabhai emphasize the importance of a space programme in his quote: –

“There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the moon or the planets or manned space- flight. But we are convinced that we are to play a meaning full role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society”. – Vikram Sarabhai

Now, Let’s understand the Word ‘Remote Sensing’

Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance without being a physical contact typically from satellite or aircrafts.

Remote Sensing

In other word, Remote sensing is an Art and Science of collecting information about object, area and phenomenon or the science of obtaining information about object or an area from a distance.

Is Remote Sensing a Science?

Remote sensing is a tool or techniques similar to other scientific discipline like mathematics. Which uses sophisticated sensors to measure the amount of electromagnetic radiation (EMR) existing an object or geographic area and then extracting valuable and quantitative information from the remotely sensed data using mathematically and statistically based algorithms is a scientific activity.


(Source: John R, Jensen, 2007)

The Diagram represents the interaction and relationship of GI-Sciences and their relation to Physical science, Social Science and Biological science with mathematics and logics.

Is Remote Sensing an Art?

The interpretation of Image is not only limited to Scientific knowledge but all of the experiences that a person has obtained in a lifetime. The alliance of scientific knowledge with real world experience allows the interpreter to develop interrogative thumb rules to extract information from the remotely sensed data.

Thus, Remote sensing image interpretation can be understanding in both ways as an art and Science and can be defined as art and science for extracting information from remotely sensed data.

Indian Satellite: The satellite is an artificial object which has been deliberately put into space for different purposes such as remote sensing, weather forecasting, image mapping, education, and research. India has been successfully launching satellites of various types since 1975. The Indian Space Research Organization (ISRO) is considered is the sole space agency of India and was established in 1969.

Space ISRO

There are number of Indian satellite available launched in different years for the specific purposes and application.

Table 1: List of Indian Satellites, Launch Year (1975-2020) and their importance

S.No.SatelliteLaunch yearImportanceS.NoSatelliteLaunch yearImportanceS.No.SatelliteLaunch yearImportance
1Aryabhata1975First Indian Satellite. It gave valuable technological know-how about satellites.35INSAT-3C2001Designed to provide continuity of the services of INSAT-2C and augment the existing INSAT capacity for communication and broadcasting.69GSAT-72013Advanced multi-band communication satellite dedicated for military purpose
2Bhaskara-I1979First experimental remote sensing satellite that carried TV and microwave cameras.36Kalpana-1 (METSAT)2002First meteorological satellite built by Indian Space Research Organisation.70Mars Orbiter Mission (MOM)2013India’s first Mars orbiter
3Rohini Technology Payload1979The first Indian launch vehicle.37INSAT-3A2003Multipurpose satellite for communication, broadcasting, and meteorological services along with and Kalpana-1 and INSAT-2E.71GSAT-142014Geostationary communication satellite
4Rohini RS-11980India’s first indigenous satellite launch.38GSAT-22003Experimental satellite for the 2nd developmental test flight of GSLV.72IRNSS-1B2014Second satellite in the Indian Regional Navigation Satellite System
5Rohini RS-D11981Launched by the first developmental launch of SLV-3 and carried a solid-state camera.39INSAT-3E2003Communication satellite to augment the existing INSAT System73IRNSS- 1C2014Third satellite in the Indian Regional Navigation Satellite System
6Ariane Passenger Payload Experiment1981First experimental communication satellite.40RESOURCESAT-1 (IRS-P6)2003Most advanced Remote Sensing Satellite74GSAT-162014communication satellite
7Bhaskara-II1981Second experimental remote sensing satellite.41EDUSAT (GSAT-3)2004India’s first satellite exclusively for education75IRNSS-1D2014Fourth satellites in the Indian Regional Navigation Satellite System
8INSAT-1A1982First operational multipurpose communication and meteorology satellite.42HAMSAT2005Microsatellite for radio services to national and international community76GSAT-62014Communication satellite
9Rohini RS-D21983Carried a smart sensor camera.43CARTOSAT-12005Earth observation satellite77Astrosat2015India’s first dedicated multi-wavelength space Observatory
10INSAT-1B1983Very successful. Revolutionized TV, radio, and telecommunications.44INSAT-4A2005Direct-to-home(DTH) TV broadcasting78GSAT-152015Communications satellite, carries GPS Aided GEO Augmented Navigation (GAGAN) payload
11SROSS-11987No remarkable achievement.45INSAT-4C2006Geosynchronous communications satellite79IRNSS-1E2016Fifth satellite in the Indian Regional Navigation Satellite System
12IRS-1A1988Earth observation satellite.46CARTOSAT-22007Remote sensing satellite-carrying panchromatic camera80IRNSS-1F2016Sixth satellite in the Indian Regional Navigation Satellite System
13SROSS-21988No remarkable achievement.47SRE-1 (Space Capsule Recovery Experiment)2007Test satellites to show an orbiting platform for performing tests in microgravity conditions81IRNSS-1G2016Seventh and final satellite in the Indian Regional Navigation Satellite System
14INSAT-1C1988No remarkable achievement.48INSAT-4B2007Similar to INSAT-4A82CARTOSAT-2C2016Earth observation remote sensing satellite
15INSAT-1D1990Still operational.49INSAT-4CR2007Identical to INSAT-4C83INSAT-3DR2016An advanced meteorological satellite of India configured with an imaging System and an Atmospheric Sounder.
16IRS-1B1991Earth observation satellite.50CARTOSAT-2A2008Similar to CARTOSAT-284SCATSAT-12016Miniature satellite to give climate anticipating, tornado expectation, and tracking services to India.
17SROSS-C1992Carried gamma-ray astronomy and aeronomy payload.51IMS-12008Low-cost micro-satellite85CARTOSAT-2D2017The highest number of satellites (104 satellites) launched by a single launch vehicle.
18INSAT-2DT1992It was launched as Arabsat 1C.52Chandrayaan-12008India’s first lunar probe86CARTOSAT- 2F2018CartoSat-2F is the 6th satellite in the Cartosat series to be built by ISRO.
19INSAT-2A1992First satellite in the second-generation Indian-built INSAT-2 series.53RISAT-22009Radar imaging satellite87MICROSAT- TD2018This satellite is a technology demonstrator and the forerunner of future satellites.
20INSAT-2B1993Second satellite in INSAT 2 series.54ANUSAT2009Research Microsatellite developed by Anna University88INS -1C2018This is the third satellite in the Indian Nanosatellite series, which carried a Miniature Multispectral Technology Demonstration (MMX-TD) Payload.
21IRS-1E1993Earth observation satellite.55Oceansat-22009Collects oceanographic, coastal and atmospheric data89GSAT- 6A2018This satellite is a high power S-band communication satellite configured around I-2K bus.
22SROSS-C21994No remarkable achievement.56GSAT-42010Communications satellite technology which failed during the mission90IRNSS -1I2018This satellite is the 6th in the series and facilitates GPS navigation.
23IRS-P21994Earth observation satellite. Launched by second developmental flight of PSLV.57CARTOSAT-2B2010Earth observation/remote sensing satellite.91GSAT-292018This satellite facilitates high-throughput communication.
24INSAT-2C1995Still in operation. Has television outreach beyond Indian boundaries.58GSAT-5P /INSAT-4D2010Mission failed92HySYS2018It facilitates Hyperspectral imaging services for agriculture, forestry, and military applications.
25IRS-1C1995Earth observation satellite.59RESOURCESAT-22011Remote-sensing satellite93ExseedSat-120181st privately funded satellite of India.
26IRS-P21994Earth observation satellite.60INSAT-4G2011C-band communication satellite94GSAT-112018Heaviest spacecraft of India.
27IRS-P31996Earth observation satellite.61Youthsat2011Indo-Russian stellar and atmospheric satellite95GSAT-7A2018Facilitates services for Indian Army and Air Force.
28INSAT-2D1997Inoperable since 1997-10-04 due to power bus anomaly.62GSAT-122011communication satellite96Microsat-R2019This satellite facilitates Earth imaging for defense purposes.
29IRS-1D1997Earth observation satellite.63Megha-Tropiques2011Indo-French collaborative effort to research on water cycle in the atmosphere97KalamSAT-V22019It is the world’s lightest satellite.
30INSAT-2E1999Multipurpose communication and meteorological satellite.64RISAT-12012First indigenous all-weather Radar Imaging Satellite98GSAT-312019This is a high-throughput Telecommunication Satellite.
31IRS-P4 OCEANSAT1999Earth observation satellite carrying a Multifrequency Scanning Microwave Radiometer (MSMR)and an Ocean Colour Monitor (OCM).65GSAT-102012advanced communication satellite99EMISAT2019This facilitates Electromagnetic intelligence to track any enemy radars for the IAF.
32INSAT-3B2000Multipurpose communication satellite.66SARAL2013Mission for oceanographic studies100Chandrayaan-22019India’s second lunar exploration mission.
33GSAT-12001Experimental satellite for the first developmental flight of GSLV-D1.67IRNSS-1A2013Seven spacecraft constituting the IRNSS space segment101Cartosat-32019Cartosat-3 is one of the optical satellites with the highest resolutions in the world.
34Technology Experiment Satellite (TES)




2001Experimental satellite to test new reaction control system, high-torque reaction wheels, and attitude and orbit control system.68INSAT-32013Meteorological Satellite102GSAT-302020GSAT-30 is the 41st communication satellite launched by ISRO to replace INSAT-4A. It provides advanced telecommunication services to the entire Indian subcontinent.

Overview of remote sensing in environmental studies:

The remotely sensed data provide valuable information for mapping and monitoring the environmental processes since long time.  There are number of remotely sensed data available from different sensors of various platform with a wide range spatial-temporal, radiometric and spectral resolution provides the best source of data for wider applications and studies. There are number of application where remotely sensed data can be utilized as primary input such as environmental mapping and monitoring, Hydrological modelling, watershed mapping, management and development, energy and water flux estimation, urban modelling, drought predictions, climate change etc.

A State of art of satellite sensors widely used in environmental application and natural resource management. These Sensors provides spatial and temporal data in a wide range of scale, radiometry, numbers of band, band width and provide distinct advantage of consistency of data, synoptic coverages, global reach, cost per unit area, repeatability, precision and accuracy.

Application of Remote Sensing in various domains

There are many different fields of study where Remote sensing techniques and Remotely sensed data is extensively utilized like environment mapping and monitoring and Agriculture etc.  there is also other diversity of application where this techniques and associated data can be potentially utilized to extract meaningful information of the geographical area.

The Majority of application has been focused on natural environments over the past decades. The Application of remote sensing in urban domain is comparatively new and gaining more research interest in the geospatial community with the advent of high-resolution imagery and more capable techniques and has application in socio economic sectors. There are numbers of techniques developed for mapping and monitoring the Urbanization and for sustainable planning and development.

The Role of remote sensing in understanding hydrological processes and fluxes across different spatial and temporal can be tremendous, if appropriate spatial and temporal resolution data are available under ranges of bands. There are three main categories mapping of watersheds and features, indirect hydrological parameter estimation and direct estimation of hydrological variables. Similarly, there are other application of soil, water and drought monitoring, agriculture, forest ecosystem, Snow and Glacier, climate change and others respectively where remote sensing techniques and datasets at different resolution is extensively utilizing for the specific purposes and the investigations.

Future Direction of Remote Sensing

The Advancement made in space-borne remote sensing in the past years has been phenomenal which leads to increasing several innovations in multiple directions. The Future development and advancement lead to availability of data from multiple sensors with wide array of spatial, spectral and radiometric characteristics which will be certainly available from multiple sources. Second, micro satellite with capability in collecting data for specific geographic location are likely to become more attractive and gain special interest among researchers and other, the advancement in hyperspectral and hyperspatial brings new challenges in data mining processing and backups and retrieval. Thus, the Future advancement in remote sensing brings more challenges, innovations, wide coverage data availability, developments and applicability in diversity of application will be prime interest among researchers or scientific communities. 


Jensen J.R. Remote Sensing of the Environment: An Earth Resource Perspective. 2nd Ed. Prentice-Hall, Inc.; Upper Saddle River, NJ: 2000. p. 544.
Lillesand, T.M. Kiefer, R.W., 2002, Remote sensing and image interpretation, Fourth edition, pp.192-193. 

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Chanchal Gupta
Indian Institute of Science, Bangalore
Email: [email protected]

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