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Space Technology India- GSLV and GSAT

India has made huge progress in space technology in the last few decades. It has achieved self-reliance in the launch of remote sensing satellites through PSLV. However, it still lacks the capacity to launch communication satellites because of the lack of indigenous Geosynchronous Satellite Launch Vehicle. The recent successful launch of GSLV Mark 3 fills this void to some extent, with this India has entered into the elite group of countries capable of launching heavy satellites in space. GSLV Mark III also referred to as the Launch Vehicle Mark 3 (LVM3) is a medium-lift launch vehicle developed by the Indian Space Research Organization (ISRO).

GSLV Mark 1:  It used Russian made Cryogenic Engine.

GSLV Mark 2: It used indigenously developed Cryogenic Upper Stage (CUS); had launch capability of 2 – 2.5 tons into Geosynchronous Transfer Orbit (GTO).

GSLV Mark 3


  • GSLV-Mark 3 is capable of launching 4 tons of satellites in the Geosynchronous Transfer Orbit (GTO) or 8 tons in a Low Earth Orbit (LEO).
  • Indigenous Cryogenic Engine: Liquid propellants — liquid hydrogen as fuel and liquid oxygen as oxidizer.
  • It took more than 25 years, 11 flights and over 200 tests on various components of the rocket to make it a reality.
  • Weight – 640 tons, Height – 43 meters.
  • GSLV-Mark 3 first developmental flight, D1, carried GSAT-19 satellite on 5th June 2017
  • Three-Stage Launch Vehicle: 2 solid motor strap-on (S200), a liquid propellant core stage (L110) and a cryogenic stage (C-25).
  • GSLV Mark 3 is the 5th generation launch vehicle developed by ISRO.

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GSLV Mark 3 – Significance for India

  • Making India Self-Reliant: Earlier India was dependent upon other countries like France for launching satellites beyond 2.3 tons.
  • More Fuel Efficient: Liquid propellant produces more amount of energy per unit mass, because of which the amount of fuel to be carried decreases. The cryogenic engine provides huge thrust to GSLV in the final stage, keeping the fuel loads relatively low.
  • Environment-Friendly: Hydrogen and Oxygen are clean fuels and when they combine they only produce water.
  • Technical Superiority: Usage of an indigenous made lightweight cryogenic engine has made India 6th country after USA, France, Japan, China, and Russia to have this technology.
  • Reduced Launching Cost: Cryogenic engine used in GSLV Mark 3 is more cost efficient.
  • New Commercial Opportunities: GSLV Mark 3 provides ISRO with new opportunities for launching satellites of foreign countries. This will also improve the forex reserves of the country.
  • Lesser Propulsion Stages: This has reduced the number of control systems, making Mark 3 more robust.
  • Mark 3 has doubled the launching capability of India. It is capable of lifting payloads up to 4 tons.
  • Lithium-ion Battery Developed Indigenously: This will reduce the dependence of such batteries from other countries and will also help meet the huge demand of such batteries in the country.
  • It gives a boost to space diplomacy of India.
  • Mark 3 has made ISRO more optimistic for future projects like Aditya L1, Chandriyan 2, Gaganyaan etc.
  • A big boost to Make in India
  • Thrust to Manned Mission: Technologies used in Mark 3 can be used to transport Indians into space in the future.

Difference between GSLV and PSLV

GSLV Mark 3 has a lifting capacity of 4 tons. PSLV has a lifting capacity of 1 ton.
GSLV has 3 stages solid, liquid and cryogenic PSLV has 4 stages that alternate between solid and liquid fuels.
Designed to deliver communication satellites Designed to deliver earth observation / remote sensing satellites.
GSLV being a newer technology, so it is not easy to comment about the success rate. ISRO has mastered PSLV, has a higher success rate.



The GSAT (Geosynchronous Satellites) are communication satellites developed indigenously by India. It will be used for digital video, data and audio broadcasting. As of 14 November 2018, 19 GSAT satellites have been launched by ISRO, out of which 13 satellites are currently in service. The GSAT series of satellites is a system developed by ISRO with an objective to make India self-reliant in broadcasting services.

The repertoire of 10 GSAT satellites, a total of 168 transponders (out of which 95 transponders are leased out to provide services to the broadcasters) in the C, Extended C and Ku-bands provides services to telecommunications, television broadcasting, weather forecasting, disaster warning and search and rescue operations.

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  • GSAT 29 is a multi-band, multi-beam satellite designed to improve the communication requirements of users from remote areas especially from Jammu & Kashmir and North-Eastern regions of India.
  • With a mission lifespan of about 10 years, it will improve internet connectivity in the country.
  • Ku-band, Ka-band and Q/V-Band communication payload onboard GSAT 29 will not only help in bridging the digital divide in the country but will also serve as a testbed for several future technologies.
  • GSAT-29 – weight – 3,136 kg.
  • Geo High-Resolution Camera onboard GSAT 29 will provide high-resolution images.
  • For the first time, a high-resolution camera is placed in higher Geostationary Orbit (GEO) of around 36,000 km.

GSAT-9 (South Asia Satellite)

    • Launched on 5th May 2017 the South Asia Satellite, also known as GSAT-9, is a geostationary communications and meteorology
    • The satellite is operated by Indian Space Research Organization (ISRO).
    • The idea for the satellite was first mooted by Indian Prime Minister Narendra Modi during 18th SAARC summit held in Nepal in 2014.
  • GSAT-9 provides telemedicine, tele-education, e-banking, television broadcasting, disaster management, weather forecasting facilities to the participating countries.
  • Afghanistan, Nepal, Bhutan, Maldives, Bangladesh and Sri Lanka are the users of the multi-dimensional facilities provided by the GSAT-9.
  • This satellite helps to implement Neighborhood First Policy of Narendra Modi government.
  • Pakistan opted out of the project, stating that it was working on its own satellite. The satellite was initially named “SAARC Satellite” but it was subsequently changed to South Asia Satellite after Pakistan refused to join the project.
  • With a lift-off mass of 2230 kg, the satellite is equipped state of the art remote sensing technology which will provide real-time weather data.
  • GSAT-9 will improve communication technologies of South Asian countries through its Ku-band
  • The total cost of the satellite is ₹450 crore, but it will be absolutely free for the participating countries.
  • The satellite was initially launched in an oval orbit 169 km at the nearest and 36,105 km at the farthest, “with an orbital inclination of 20.65 degrees with respect to the Equator. The orbit was later made circular through many maneuvers.
  • With GSAT 9 South Asia has taken a giant step towards regional integration.

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Hyperspectral Imaging Satellite (HySIS)

  • On 29th November 2018, ISRO launched HySIS along with 30 other foreign satellites from Satish Dhawan Space Centre in Sriharikota with the help of PSLV C43.
  • HySIS is India’s first hyperspectral imaging satellite for advanced earth observation.
  • HysIS will help in the study of Earth’s surface in visible, near-infrared and shortwave infrared regions of the electromagnetic spectrum.
  • It can see 55 spectral or color bands from 630 km above ground. Its weight is 380 kg.
  • It will be India’s first full-scale working satellite with this capability.
  • It will provide high definition images to help identify objects on Earth with more precision than regular optical or remote sensing Satellites.
  • The technology will have various applications in the fields like defense, agriculture, land use, minerals, environment etc.
  • It contains a very important indigenously developed chip called an “optical imaging detector array’”.
  • The satellite lifespan is 5 years till the year 2023.
  • In May 2008, 83-kg IMS-1, an experimental satellite with hyspex imaging technology was launched by ISRO.
  • In 2008 hyperspectral camera was mounted on Chandrayaan-1 to map lunar mineral resources.
  • The countries whose foreign satellites are launched: US (22 nanosatellites and one microsatellite), Australia, Canada, Colombia, Finland, Malaysia, Netherlands, and Spain.

Hyperspectral Imaging

  • Hyperspectral imaging or hyspex imaging combines digital imaging and spectroscopy.
  • It collects and analyzes information from across the electromagnetic spectrum.
  • Hyspex helps to identify objects on Earth by reading the spectrum for each pixel of a scene from space.


This is an important current affairs topic in technology/national section for UPSC IAS exam preparation and other competitive exams like RBI Grade B preparation, Nabard Grade A/B preparation, UGC NET preparation etc.

Space technology is a growing field, and recently we have seen private players like SpaceX venturing into this space. It can be a great career for Mtech student. Students appearing for GATE exam should keep in touch with this topic. See gate paper pattern

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