Geosynchronous Satellite Launch Vehicle

The Geosynchronous Satellite Launch Vehicle ( GSLV ) is an Indian launch vehicle, developed by the Indian Space Agency ISRO to carry communication satellites of the type INSAT in a geostationary orbit and to make India independent in the field of foreign launch service providers.

  • 3.1 Performed offs
  • 3.2 Planned start


The GSLV is based on the PSLV, however, it added additional liquid-fuel boosters and a cryogenic upper. It is a three stage launch vehicle having a solid -driven first stage, a liquid fuel- driven second stage, and third stage of the cryogenic. The first two steps have been taken from the PSLV, the third stage is made in Russia. India ordered a total of seven upper stages of Russia and wanted to buy the plans for this, but because of U.S. intervention did not take place this technology transfer. India therefore had to develop the cryogenic upper stage itself, which, however, lasted eleven years.

The GSLV uses four L40 liquid propellant boosters ( LRB ) and can carry up to 5 tons in a slightly eastern LEO. With the help of Russian cryogenic upper 12KRB it can carry 2.2 tonnes in a 18 ° GTO.


In the MkI and MkII four liquid-propellant boosters are used. Each of the four L40 booster contains two independent tanks which together contain 40 tons Hypergol fuel (UH 25 and dinitrogen tetroxide ). The boosters have a diameter of 2.1 meters and are each a 680 kN Viking strong engine.

In the MkIII these are to be replaced by two large S200 Large Solid Booster (LSB ) with 200 tonnes of solid propellant. This allows the starting mass of the entire rocket to 630 tons and payload capacity for the GTO rises to 4-5 tons.

First stage

The first step S125 ( MkIa ) or S139 ( MkIb ) has a diameter of 2.8 m and is made ​​of maraging steel. It is a solid-fuel rocket and contains 125 t and 139 t of solid propellant.

Second stage

The second stage also has a diameter of 2.8 m and can be loaded with 37.5 tons of liquid fuel (UH 25 and nitrogen tetroxide ). The two separate tanks are made from a special aluminum alloy. The stage provides a thrust of 720 kN.

Third stage

The third stage 12KRB the Russian manufacturer GKNPZ Khrunichev uses liquid hydrogen (LH2 ) and liquid oxygen ( LOX), also here in two independent tanks of aluminum alloy. A total of 12.6 tonnes of fuel can be added, the engine KVD- 1 provides a thrust of 7.5 kN, has a specific impulse of 454 s and can be fired twice in the air.

The first three flights of the GSLV used all still the Russian cryogenic upper. In the fourth start on 15 April 2010 for the first time an Indian third stage was used, which also LH2 and LOX burns and should provide KRB something more thrust than 12. This should settle heavier payloads in Geotransferorbit the MkII now called rocket. After the ignition of the third stage, the Vernierdüsen not seem to work, so that the rocket went out of control and crashed into the sea.


The GSLV -D5 several design improvements were introduced. These consist of a redesign of the lower fairing that protects the cryogenic upper stage during atmospheric flight, the revision of the wire tunnel of the cryogenic upper stage to withstand the forces encountered during flight better, a revised aerodynamic design of the entire missile and installation of video systems for monitoring the movements of the outer shell of the rocket during the various phases of flight. The improvements of the cryogenic upper stage include a modified design of the Kraftstoffturbopumpem ( FBTP ) to the change in size of the bearings and housing ensure changes in temperature by cryogenic fuels, a change in the ignition sequence to the successful and sustainable ignition for the main (ME) and control thrusters ( SE) and the gas generator (GG) ensure. In addition, some critical systems such as the polyimide fuel lines and liquid oxygen and liquid hydrogen level sensors were replaced by Indian-built to better prevent the possible contamination during transport.


  • Overall height: 49 m
  • Take off weight: 401 t
  • Number of levels: 3
  • Target orbit: GTO 180 × 36,000 km


The first two flights of GSLV were pure test flights. The first partially successful, was launched in April 2001 with the satellite GSAT -1 on board. The second, this time successful launch of a GSLV in May 2003 and brought the experimental communication satellite GSAT -2 into space. The first operational launch was on 20 September 2004 with the EDUSAT communications satellite as a payload.

Performed start

This is a complete start list of the Geosynchronous Satellite Launch Vehicle. State of the list: January 10, 2014

¹ Gross Weight = ( Satellite Adapter, enclosure etc. )

² NOT necessarily the target orbit of the payload, but the path on which the payload of the advanced level should be suspended / was.

Planned start

State of the list: January 10, 2014