GSLV is a three stage rocket designed to inject 2 to 2.5 ton class of satellites into Geostationary Transfer Orbit.
The first stage of rocket is fired by solid fuel and its four strap-on motors by liquid fuel.
The second stage is powered by liquid fuel and the third stage by the cryogenic engine which is more efficient as it provides more thrust for every kilogram of propellant burnt
Significance: ISRO is perfecting the crucial cryogenic engine technology in order to save precious foreign exchange by launching heavier satellites on its own. Currently, ISRO relies on the European Space Agency (ESA’s) Ariane rocket to launch its heavy communication satellites