Geo-Synchronous Satellite Launch Vehicle (GSLV)


Geo-Synchronous Satellite Launch Vehicle (GSLV)

ISRO  developed a Geo-Synchronous Satellite Launch Vehicle (GSLV) by incorporating the PSLV solid and liquid stage technologies for the booster system and a cryogenic upper stage as a third stage. This vehicle is about 49 m tall with a lift-off mass of 400 t. 

 First stage of GSLV
The first stage of GSLV comprises of solid propellant motor and four liquid propellant strap-on motors derived from the PSLV second stage. First stage is 20.3 m long and 2.8 m in diameter and carries 129 tons of Hydroxyl Terminated Poly Butadiene (HTPB) based solid propellant. The stage develops about 4700 kN thrust and burns for 100 s. 
 Four strap-on stages

The four strap-on stages are 19.70 m long and 2.1 m in diameter. The strapon liquid stage adopts VIKAS engine and stage is loaded with 40 tons of hypergolic propellants, namely, Unsymmetrical Di-Methyl Hydrazine (UDMH) as fuel and Nitrogen Tetroxide (N2O4) as oxidizer, stored in two separate tanks.
 Second stage of GSLV

The second stage of GSLV is 11.6 m long and 2.8 m in diameter and loaded with 37.5 tonne of UDMH and N2O4 in two compartments of an aluminium alloy tank separated by a thin metal sheet known as common bulkhead. The VIKAS engine used for the second stage employs a turbo-pump system producing a thrust of about 700 kN in vacuum.


 Third stage of GSLV
  The third stage of GSLV uses a Cryogenic Stage (CS) which is procured from Russia. The stage, that employs liquid hydrogen and liquid oxygen as fuel and oxidizer respectively. It is 8.7 m long and 2.9 m in diameter. Liquid hydrogen and liquid oxygen (LOX) are stored in two separate aluminium alloy tanks.  With a propellant loading of 12.5 tonne, the stage can burn for duration of about 750 s producing a nominal thrust of 75 kN.
 The heat shield which protects the spacecraft during the flight is of 3.4 m diameter and 7.8 m long. 








 The first flight of GSLV was on April 18. 2001 and it successfully launched G-SAT spacecraft of 1540 kg into geo-synchronous transfer orbit. 

The overall lift-off mass of the vehicle - 400 tons
Length of vehicle                                  - 49m

Payload capacity of PSLV : 

Low Earth Orbit (LEO)                        - 4.5 tons
Sun Synchronous Polar Orbit (SSPO)   - 2.2 tons

Geo Transfer orbit (GTO)                     - 2 ton.