Geo-synchronous Satellite Launch Vehicle is about 51 meter tall weighing 400 tones. It is able to place a payload of over two tones in geostationary transfer orbit.
This vehicle has been very helpful in planking INSAT satellites in geostationary orbit, about 36000 km over the equator, which are being used for telecommunication, television broadcasting and meteorological services.
GSLV is being planned to develop in two phases. In first GSLV Mark-I having the core vehicle as PSLV with solid propellant first stage motor and liquid stage of PSLV are employed in it. In Second phase i.e. GSLV Mark-II is to be developed by using cryogenic engine.
The GSLV project in India was initiated in 1990 and the first test flight of GSLV was conducted on April 18, 2001, when the 1540kg experimental satellite, GSAT-I was placed in GTO. GSLV is a three-stage vehicle:
The first stage of GSLV comprises a solid propellant motor and four liquid propellant strap-on motors. Its motor is made of high strength steel. It carries 129 tonne of Hydroxyl Terminated Poly Butadiene. This stage is credited to develop about 4700 kilo Newton thrust and burns for 100 seconds.
The second stage of GSLV is 11.6m long and 2.8m diameter. The engines used for the second stage employ a turbo-pump fed engine producing a thrust of 700 kilo Newton. Here fuel used is similar to I stage.
Stage- III (Cryogenic Engine)”:
The third stage of GSLV uses a cryogenic stage procured from Glavkosmos, Russia. This stage employs liquid hydrogen and liquid oxygen as fuel and oxidizer respectively.
The liquid hydrogen and liquid oxygen are stored in two separate aluminum alloy tanks connected by an interstate structure. With a propellant loading of 12.5 tones, the stage can burn for duration of about 750 seconds producing a nominal thrust of 75 kilo Newton.