Sunday, December 26, 2010

GSLV flights jinxed

Geo-synchronous Satellite Launch Vehicle (GSLV) flights from Sriharikota seem to be jinxed. Out of seven GSLV flights from 2001 till the latest flight on December 25, 2010, four have failed. The previous GSLV flight on April 15, 2010 also ended in failure.

The very first flight in March 2001 was aborted one second before the lift-off because one of the four strap-on booster motors around the core first stage did not develop adequate thrust. So the computer aboard the rocket aborted the flight. Indian Space Research Organisation's rocket engineers solved the problem in less than a month and the flight took place on April 18, 2001. But the Russian cryogenic stage atop the vehicle underperformed and the satellite GSAT-1 was put in lower orbit than targeted. So the ISRO had to fire the liquid apogee booster motor on board the satellite more than needed to put the vehicle in the geo-synchronous orbit. Thus precious fuel was lost and the satellite ultimately came down in its orbit. The mission ended in failure.

The next two GSLV flights were a big success and they put their satellites in orbit. But the flight of the GSLV-F02 on July 10, 2010, with INSAT-4C, ended in failure because of a manufacturing defect in one of the components of four strap-on booster motors. The vehicle was destroyed in mid-flight by the Range Safety Officer and its debris fell into the sea. The ISRO salvaged some parts of the vehicle from the Bay of Bengal.

The third failure took place on April 15, 2010 when the GSLV-D3 did not put GSAT-4 in orbit. This flight had raised a lot of hopes because it carried an indigenous cryogenic engine. It did not succeed due to the failure of the fuel booster turbo pump in the Indian cryogenic upper stage. There were two reasons for this failure — gripping at one of the seal locations and seizure of rotor rupture of turbine casing caused probably by excessive rise in pressure and temperature.

The GSLV-F06 flight on Saturday has also ended in failure because a command to control the vehicle did not reach the actuator in the first stage of the vehicle. This vehicle carried a Russian cryogenic stage in the third topmost stage.

After a delay of five days, because of leak of helium gas from one of the valves in the Russian cryogenic stage, the GSLV-F06 finally took off on Saturday.

While it cost Rs. 175 crore to build the GSLV-F06, for the GSAT-5P it cost Rs. 150 crore.

The GSLV is a three-stage vehicle, with the first core stage powered by solid propellants, four strap-on motors around the core stage, which are fuelled by liquid propellants, the second stage propelled by liquid propellants and the third topmost stage uses cryogenic propellants.

No comments:

Post a Comment