A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word satellite refers to a machine that is launched into space and moves around Earth or another body in space. There are so many types of satellites like: Communication Satellites, Earth Observation Satellites, Navigation satellites, scientific Exploration satellites, experimental satellites, small satellites etc launched by ISRO.
A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word “satellite” refers to a machine that is launched into space and moves around Earth or another body in space. There are so many types of satellites like: Communication Satellites, Earth Observation Satellites, Navigation satellites, scientific & Exploration satellites, experimental satellites, small satellites etc. launched by ISRO.
A. Communication Satellites: The Indian National Satellite (INSAT) system is one of the largest domestic communication satellite systems in Asia-Pacific region with nine operational communication satellites placed in Geo-stationary orbit. Established in 1983 with commissioning of INSAT-1B, it initiated a major revolution in India’s communications sector and sustained the same later. Currently operational communication satellites are INSAT-3A, INSAT-3C, INSAT-3E, INSAT-4A, INSAT-4B, INSAT-4CR, GSAT-8, GSAT-10 and GSAT-12.
The system with a total of 195 transponders in the C, Extended C and Ku-bands provides services to telecommunications, television broadcasting, satellite news gathering, societal applications, weather forecasting, disaster warning and Search and Rescue operations.
List of Communication Satellites:
| Launch Date | Launch Mass | Power | Launch Vehicle | |
| GSAT-15 | Nov 11, 2015 | 3164 kg | Solar array providing 6200 Watts and Three 100 AH Lithium-Ion batteries | N/A |
| GSAT-6 | Aug 27, 2015 | 2117 kg | Generated power 3100 W | N/A |
| GSAT-16 | Dec 07, 2014 | 3181.6 kg | Solar array providing 6000 Watts and two 180 AH Lithium lon batteries | Ariane-5 VA-221 |
| GSAT-14 | Jan 05, 2014 | 1982 kg | 2600 W | GSLV-D5 |
| GSAT-7 | Aug 30, 2013 | 2650 kg | 3,000 W | Ariane-5 VA-215 |
| INSAT-3D | Jul 26, 2013 | 2060 Kg | 1164 W | Ariane-5 VA-214 |
| GSAT-10 | Sep 29, 2012 | 3400 kg | 6474 Watts | Ariane-5 VA-209 |
| GSAT-12 | Jul 15, 2011 | 1410 kg | 1430 Watts | PSLV-C17 |
| GSAT-12 | Jul 15, 2011 | 1410 kg | 1430 Watts | PSLV-C17 |
| GSAT_8 | May 21, 2011 | 3093 kg | 6242 Watt | Ariane-5 VA-202 |
| GSAT-5P | Dec 25, 2010 | 2310 kg | N/A | GSLV-F06 |
| GSAT-4 | Apr 15, 2010 | 2220 Kg | N/A | GSLV-D3 |
| INSAT-4CR | Sep 02, 2007 | 2,130 kg | 3000 W | GSLV-F04 |
| INSAT-4B | Mar 12, 2007 | 3025 Kg | 5859 W | Ariane5 |
| INSAT-1B | Aug 30, 1983 | N/A | Shuttle [PAM-D] | |
| INSAT-1A | Apr 10, 1982 | N/A | Delta |
B. Earth Observation Satellites: Starting with IRS-1A in 1988, ISRO has launched many operational remote sensing satellites. Today, India has one of the largest constellations of remote sensing satellites in operation. Currently, eleven operational satellites are in orbit – RESOURCESAT-1 and 2, CARTOSAT-1, 2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, Megha-Tropiques and SARAL. Varieties of instruments have been flown onboard these satellites to provide necessary data in a diversified spatial, spectral and temporal resolutions to cater to different user requirements in the country and for global usage.
The data from these satellites are used for several applications covering agriculture, water resources, urban planning, rural development, mineral prospecting, environment, forestry, ocean resources and disaster management.
List of Earth Observation Satellites
| Name of Satellites | Launch Date | Launch Mass | Power | Launch Vehicle |
| SARAL | Feb 25, 2013 | 407 kg | 906 W | PSLV-C20 |
| RISAT-1 | Apr 26, 2012 | 1858 kg | 2200 W | PSLV-C19 |
| Megha-Tropiques | Oct 12, 2011 | 1000 kg | 1325 W | PSLV-C18 |
| RESOURCESAT-2 | Apr 20, 2011 | 1206 kg | 1250 W | PSLV-C16 |
| CARTOSAT – 2B | Jul 12, 2010 | 694 kg | 930 W | PSLV-C15 |
| Oceansat-2 | Sep 23, 2009 | 960 kg | 1360W | PSLV-C14 |
| RISAT-2 | Apr 20, 2009 | 300 kg | PSLV-C12 | |
| Bhaskara-II | Nov 20, 1981 | 444 kg | 47 W | C-1 Inter-cosmos |
| RS-D1 | May 31, 1981 | 38 kg | 16 W | SLV-3 |
| Bhaskara-I | Jun 07, 1979 | 442 kg | 47 W | C-1Intercosmos |
C. Experimental Satellites: ISRO has launched many small satellites mainly for the experimental purposes. This experiment includes Remote Sensing, Atmospheric Studies, Payload Development, Orbit Controls, recovery technology etc.
| Launch Date | Launch Mass | Power | Launch Vehicle | Orbit Type |
| SRE – 1 | Jan 10, 2007 | 550 kg | ||
| Apple | Jun 19, 1981 | 670 kg | 210 | Ariane -1(V-3) |
| RS-1 | Jul 18, 1980 | 35 kg | 16 Watts | |
| RTP | Aug 10, 1979 | 35 kg | ||
| Aryabhatta | Apr 19, 1975 | 360 kg | 46 atts |
D. Navigation Satellite: To meet the Civil Aviation requirements, ISRO is working jointly with Airport Authority of India (AAI) in establishing the GPS Aided Geo Augmented Navigation (GAGAN) system. To meet the user requirements of the positioning, navigation and timing services based on the indigenous system, ISRO is establishing a regional satellite navigation system called Indian Regional Navigation Satellite System (IRNSS).
I. GPS Aided GEO Augmented Navigation (GAGAN): This is a Satellite Based Augmentation System (SBAS) implemented jointly with Airport Authority of India (AAI). The main objectives of GAGAN are to provide Satellite-based Navigation services with accuracy and integrity required for civil aviation applications and to provide better Air Traffic Management over Indian Airspace. The system will be interoperable with other international SBAS systems and provide seamless navigation across regional boundaries. The GAGAN Signal-In-Space (SIS) is available through GSAT-8 and GSAT-10.
II. Indian Regional Navigation Satellite System (IRNSS): This is an independent Indian Satellite based positioning system for critical National applications. The main objective is to provide Reliable Position, Navigation and Timing services over India and its neighbourhood, to provide fairly good accuracy to the user. The IRNSS will provide basically two types of services:
1. Standard Positioning Service (SPS)
2. Restricted Service (RS)
List of Navigation Satellites:
| Launch Date | Launch Mass | Power | Launch Vehicle | |
| IRNSS-1E | Jan 20, 2016 | PSLV-C31/IRNSS-1E | ||
| IRNSS 1D | Mar 28, 2015 | PSLV-C27 | ||
| IRNSS 1C | Nov 10, 2014 | |||
| IRNSS-1B | Apr 04, 2014 | 1432 kg | 1660 W | PSLV-C24 |
| IRNSS-1A | Jul 01, 2013 | 1425 kg | 1660 W | PSLV-C22 |
E. Scientific & Exploration: Indian space programme encompasses research in areas like astronomy, astrophysics, planetary and earth sciences, atmospheric sciences and theoretical physics. Balloons, sounding rockets, space platforms and ground-based facilities support these research efforts. A series of sounding rockets are available for atmospheric experiments. Several scientific instruments have been flown on satellites especially to direct celestial X-ray and gamma-ray bursts.
List of Scientific and exploration Spacecraft:
| Launch Date | Launch Mass | Power | Launch Vehicle | |
| Mars Orbiter Mission Spacecraft | Nov 05, 2013 | 1337 kg | 840 W | PSLV-C25 |
| Chandrayaan-1 | Oct 22, 2008 | 1380 kg | 700 W | PSLV-C11 |
| SRE-1 | Jan 10, 2007 | 550 kg | PSLV-C7 | |
| SROSS-C2 | May 04, 1994 | 115 kg | 45 W | Augmented Satellite Launch Vehicle (ASLV) |
| SROSS-C | May 20, 1992 | 106.1 kg | 45 W | Augmented Satellite Launch Vehicle (ASLV) |
| SROSS-1 | Mar 24, 1987 | 150 kg | 90 W | Augmented Satellite Launch Vehicle (ASLV) |
