Sep 20, 2004

GSLV-F01 / EDUSAT(GSAT-3)

GSLV-F01 is the third flight of ISRO’s Geosynchronous Satellite Launch Vehicle and this is the first operational flight. In its two developmental test flights conducted in April 2001 and May 2003 respectively, GSLV successfully launched GSAT-1 and GSAT-2 satellites into Geosynchronous Transfer Orbits (GTOs).

In the first developmental test flight (GSLV-D1), the vehicle placed 1530 kg GSAT-1 into GTO and in the second developmental test flight (GSLV-D2), it placed 1825 kg GSAT-2 into GTO. In its first operational flight (GSLV-F01), GSLV will launch the 1950 kg EDUSAT.

The 49 metre tall 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 and Liquid Hydrogen.

The Aluminium alloy GSLV payload fairing is 3.4 m in diameter and is 7.8 m long. 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 three-axis attitude 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 Engine Gimbal Control (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.

Satish Dhawan Space Centre (SDSC) SHAR, the launch station for GSLV, is located at 80 km north of Chennai on the east coast of India.