Indian Space Research Organisation * Hindustan Aeronautics Ltd.




 Orbital launches


Last launch





2001 - 2003






2004 - 2010





2010 - 2017


Mk.2+ (1)






Geosynchronous Satellite Launch Vehicle (GSLV)
GSLV was declared operational (GSLV Mk.1) after both its developmental test flights conducted in April 2001 and May 2003 were successful. In its first operational flight, GSLV-F01, successfully launched the 1,950 kg G-SAT 3 on September 20, 2004.
In its present configuration, the 49 metre tall, 414 tonne, GSLV is a three stage vehicle. The first stage, GS1, comprises a core motor with 138 tonne of solid propellant and four strap-on motors each with 40 tonne of hypergolic liquid propellants (UH25 and N204). The second stage has 39 tonne of the same hypergolic liquid propellants. The third stage (GS3) is a cryogenic stage with 12.5 tonne of Liquid Oxygen (LOX) and Liquid Hydrogen (LH2). The Aluminum alloy GSLV payload fairing is 3.4 m in diameter and is 7.8 m long.


The GSLV (Geosynchronous Satellite Launch Vehicle)  uses lower stage closely derived from the PSLV, with a new cryogenic third stage replacing the third and fourth stage of PSLV. In place of small solid strap-on boosters used in the PSLV, the GSLV uses four liquid boosters that are derived from the PSLV second stage. The same solid  first stage  and liquid second stage are carried over  from the PSLV. The third  stage is a cryogenic hydrogen/oxygen  upper stage. Seven stage are manufactured by Khrunishev/Russia. The GSLV payload fairing is made of aluminium and is manufactured by Hindustan Aeronautics. 

The three-axis attitude (orientation) stabilisation of GSLV is achieved by autonomous control systems provided in each stage. Single plane Engine Gimbal Control (EGC) of the four strap-ons of the first stage are used for pitch, yaw and roll control. The second stage has EGC for pitch and yaw and hot gas Reaction Control System (RCS) for roll control. Two swivellable vernier engines using LH2 and LOX provide pitch, yaw and roll control for the third stage during thrust phase and cold gas system during coast phase. The Inertial Guidance System (IGS) in the Equipment Bay (EB) housed above the third stage guides the vehicle till spacecraft injection. The closed loop guidance scheme resident in the on-board computer ensures the required accuracy in the injection conditions. GSLV employs S-band telemetry and C-band transponders for the vehicle performance monitoring, tracking, range safety/flight safety and Preliminary Orbit Determination (POD).
GSLV employs various separation systems such as Flexible Linear Shaped Charge (FLSC) for the first stage, pyro-actuated collet release mechanism for second stage and Merman band bolt cutter separation mechanism for the third stage. Spacecraft separation is by spring thrusters mounted at the separation interface.
The third stage of GSLV is cryogenic. The initial flights of GSLV (
GSLV Mk.1) use Russian supplied cryogenic stage. CUSP envisages design and development of the indigenous cryogenic upper stage to replace the Russian supplied cryogenic stage in GSLV (GSLV Mk.2).


2018, March -- ISRO confirms that GSLV F-10 will be first fully upgraded GSLV. All four L40 strapons will have high thrust VIKAS engines and well as the second stage. The upper stage will have propellant loading increased to 15 tons and thrust of CE-7.5 engine will be increased from present 7.5 tons to 9.5 tons.

Payload capability to GTO for GSLV has been increased by 70kg for GSLV F-08 mission to bring the GTO capability of GSLV up from 2.25 tons to 2.32 tons. With additional upgrades on GSLV F-10 mission later this year this will further boost GTO capability by 250 kg to bring GSLV GTO capability to 2.57 tons.

Sriharikota: Indian Space Research Organisation (ISRO) suffered a major jolt on Apr. 15, 2010 when the Geosynchronous Satellite Launch Vehicle (GSLV-D3), which was launched using an Indian-designed and built cryogenic engine for the first time, failed. The GSLV-D3 was to put the 2.2-tonne communication satellite GSAT-4 into the geo transfer orbit (GTO)
The launch was not perfect. No more data was sended 500 seconds after  lift-off. The rocket deviated from its path, and nobody did receive speed and altitude data from the vehicle. Indications were that the cryogenic engine ignited after 304 seconds after lift-off. However the vehicle tumbling and losing control as the two vernier (steering) engines may not have ignited. These two steering engines control the pitch, roll and yaw of the rocket.  The performance of the vehicle was normal up to the second stage.

ISRO has reverted to Fiber Reinforced Plastic (FRP) fairing for the launch of GSLV-D3. The GSLV-D3 rocket has a bigger fairing - four meters in diameter - as compared to the earlier rocket versions whose heat shield were of 3.4 meter diameter and were made of aluminum alloy metal.