Geo-synchronous Satellite Launch Vehicle
MISSION The Geo-synchronous Satellite Launch Vehicle (GSLV) is designed to place satellites in Geo-synchronous Transfer Orbit (GTO). It adopts the flight-proven solid and liquid stages of ISRO’s Polar Satellite Launch Vehicle (PSLV) and a cryogenic upper stage. The second developmental flight, GSLV-D2, carries an experimental communication satellite, GSAT-2, with an augmented payload of 1800 kg.
Salient Features
Overall length	: 49 m
Lift-off weight	: 414 t
No. of stages	: 3
Payload	: GSAT-2 (1800 kg)
Orbit (GTO)	: 180 x 36,000 km
GSLV is a three stage vehicle, 49 m tall. The first stage, GS1 comprises a solid propellant motor (S139) and four liquid propellant strap-on motors (L40H). The second stage (GS2) is powered by a single liquid propellant engine (L37.5H). The third stage (GS3) is a cryogenic stage (C12).
Improvements in GSLV-D2
GSLV, in its first developmental flight, GSLV-D1, carried a 1540 kg payload into GTO. For the second development flight, GSLV-D2, the payload capability has been enhanced to 1800 kg by incorporating: . Enhanced propellant loading in the core solid motor . High pressure engine in liquid propellant strap-ons and the second stage . Optimisation of structural elements
PROPULSIVE STAGES
First Stage
L 40H Stage		S139 Stage
The core first stage is 2.8 m in dia. and is made of maraging steel. It has a nominal propellant loading of 138 t. Each of the four strapon stages (L40H) is loaded with 40 t of hypergolic propellants (UH25 & N2O4) stored in two independent tanks of 2.1 m diameter. The engine produces 765 kN thrust.
Second Stage
The second stage is 2.8 m in dia and is loaded with 39 t of liquid propellants (UH25 & N2O4 ) in two compartments of an aluminium alloy stage tankage separated by a common bulkhead. This has an engine of 804 kN thrust.