The GSLV rocket on the launch pad. ISRO

The first development launch of Geo-synchronous Satellite Launch Vehicle (GSLV) is rescheduled for Wednesday, April 18, 2001 from SHAR Centre, Sriharikota. The window for the launch extends up to April 25, 2001.

It may be recalled that the first launch attempt of GSLV was aborted one second before the lift-off on March 28, 2001 by the Automatic Launch Processing System (ALS) after it detected that one of the strap-on boosters did not develop the required thrust.

Immediately following the mission abort, as worked out in advance for such contingencies, the safety systems were brought into action to protect the launch vehicle. The vehicle was safely disarmed. Subsequently, all the propellants were removed from the vehicle.

Based on a detailed analysis of the data obtained during the five seconds' operation of the four strap-on motors during the count down sequence, examination of the records of engines, tear down analysis of the disassembled engine and the extensive simulations carried out, it has been now established that the reason for one of the strap-on boosters not developing the required thrust was due to a defective plumbing in the oxidiser flow line of the engine, which had escaped detection during testing. This resulted in reduced flow of oxidiser to the engine.

Based on review of the video pictures and other data, it was concluded that the fire spreading over one of the strap-on boosters was only due to the burning of foam insulation pads and was incidental and did not cause any damage to the vehicle. It has been decided to provide additional flame protection for these insulation pads.

The anomalous engine is being replaced with a standby engine. All the other systems of the vehicle are found to be healthy.