Indian Satellite Launch Vehicles

Indian Satellite Launch Vehicles

This article deals with ‘Indian Satellite Launch Vehicles‘. This is part of our series on ‘Science and Technology’ which is important pillar of GS-3 syllabus . For more articles , you can click here

We need Launch Vehicles to place satellites in the orbit. ISRO has made various Satellite Launch Vehicles like PSLV and GSLV.

Indian Satellite Launch Vehicles


  • Polar Satellite Launch Vehicle
  • First launch – 1993
  • Payload that PSLV can carry =  upto 1600 kg
  • It is used by ISRO to launch  Indian Remote Sensing Satellites (IRS) such as Cartosat, Oceansat etc
  • Latest version ie PSLV-XL can carry upto 1750 kg.  Chandrayaan & Mars mission were launched using this.
Stages Four stages using solid and liquid fuel alternately
First – Solid fuel
– HTPB- Hydroxyl Terminated Poly-Butadiene
Second – Liquid propellant : UDMH- Unsymmetrical Di Methyl Hydrazine
– Oxidiser : Nitrogen Tetroxide
– It employs Vikas engine
Third – Solid propellant : HTPB
Fourth – Liquid propellant : Mono Methyl Hydrazine
– It also employs Vikas Engine

PSLV and importance to Indian space programme

  • Country’s  first operational launch vehicle
  • Highly successful and reliable => Has record of 97% successful launches which is one of the most successful in whole world
  • Carries IRS satellites to Polar Sun Synchronous Orbits with utmost precision
  • Potential competition to west due to lower launch price => helping to earn lot of revenue.
  • Helped launching spy satellites   => boost the national security


  • Geosynchronous Satellite Launch Vehicle
  • First launch in 2001
  • Can carry upto 2500 kg
  • For launching Indian National satellites (INSAT)  & GSAT (but most of Geostationary Satellites are around 3000 kg to 4000 kg which cant be launched by GSLV MK II & we used to be dependent on Ariane Aerospace for their launches)
  • Next version is GSLV MK-3
Stages Three stages  
First Solid propelled
Second Liquid propelled with hypergolic fuels
Third Liquid propelled in MK-2 (this stage is Cryogenic  in MK-3)
Stage 1&2 Taken over from PSLV
  • All the GSLV launches are conducted from Satish Dhawan Space centre in Sriharikota


Earlier (before June 2017) , ISRO was in  position to launch only satellites weighing between 2 &  2.5 tons into geostationary orbits. But most contemporary communications satellites are normally in the weight category of 3 to 5 tons & therefore require a more powerful launcher. India’s future missions to the Moon, Mars and Venus also need powerful launcher. Appreciating this need, ISRO has made GSLV-Mark III, a vehicle capable of placing 4 ton satellites in geostationary orbit

Latest version of GSLV

GSLV Mk-3 can Carry

  • Upto 4 ton till Geostationary Orbit
  • Upto 10 ton till Low Earth Orbit (Polar Satellites)

And it has ended our reliance  on EU’s Arianespace launch vehicle to send GSAT satellites.

GSLV MK-3 is a three stage vehicle

First Solid propellant
Second Liquid Propellant
Third Cryogenic Engine ( only difference in this stage from normal GSLV) – Fuel = Liquid hydrogen
– Oxidiser = Liquid oxygen  

India had signed MoU with Russia to transfer Cryogenic Engines to India in starting 1990s but USA pressurised Russia not to supply these to India arguing that it would violate MTCR Treaty although Cryogenic engines are not used in Missiles . Due  to this India’s programme  suffered

June 2017 – GSLV MK-III made its maiden flight from Sri Harikota placing GSAT – 19  in Geostationary Orbit .


  • The launch of GSLV Mark III will enhance India’s capability to be a competitive player in the multimillion dollar commercial launch market. It will help in earning huge foreign exchange.
  • It will end India’s dependence on foreign launch vehicles to put its heavy satellites (GSAT series) . (Earlier India was dependent on France’s Ariane space )
  • India can  send its astronauts into space using this. 
  • It will boost India’s Communication resources as cost of launching Communication Satellites will reduce
  • Cryogenic Technology used in it can be further used in making ICBM

Only USA (Saturn V), Russia (Proton M) , China (Long March 5) & European Space Agency (Ariane)  + Private player (Space X) has this capability earlier.

4. Semi Cryogenic Engine

  • MoU signed between Russian Space Agency & ISRO
  • Would be third Rocket Development Programme
  • Cost –  ₹1,800 crore
  • Capacity –  6 to 10 Ton to height of 36,000 km (more than GSLV-Mk-3)
  • Currently only Russia & US have this technology

5. Reusable Launch Vehicle

  • June 2016 – ISRO  successfully launched first technology demonstrator of the indigenously made RLV. Many more such successful launches have to be undertaken , before ISRO readies a reusable launch vehicle for commercial use.
  • In simple words, it is a winged vehicle that will take off vertically like a rocket and glide back to land horizontally like a plane
  • It will have a two-stage-to-orbit configuration.


  • Cut down  cost of launching satellites to 1/10th .  Currently, main launch cost comes from building rocket, which can be used just once, as the rockets get burnt on re-entry into atmosphere. 
  • More developed version of the vehicle could be used for manned missions

Note – No sovereign space agency has RLV for satellite launches. SpaceX is also working on this project.

6. Scramjet Engine

  • ISRO successfully conducted the Scramjet (or Supersonic Combusting ramjet) engine test. With this, India became only the fourth nation in the world to successfully flight-test a scramjet engine after United States, Russia and China.
  • Scramjet engine uses natural oxygen present in the atmosphere to burn the fuel stored in the rocket. It reduces the amount of oxidiser to be carried along with the fuel, bringing down launch costs.


  • Increases lift off mass as there will be no need to carry  liquified oxygen on board . Note:  propellant accounts for nearly 85%  of the weight of a rocket, and in that oxygen accounts for nearly 60%
  • Scramjet does not have rotating parts so the chances of failure are also measurably reduced.

7. Future Dream Project : Small Satellite Launch Vehicle

  • Dream project of ISRO chief K Sivan
  • Small satellites are being built by private industry players with advancements in electronics
  • Note : JAXA (Japan) has made this type of launch vehicle

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