ISRO to decide on delayed rocket launch Wednesday

December 21st, 2010 - 9:36 pm ICT by IANS  

ISRO Chennai, Dec 21 (IANS) The Indian Space Research Organisation (ISRO) will Wednesday take a decision on the delayed rocket launch, meant to put an advanced communications satellite into orbit, after getting results of tests on a leaking engine valve.”The tests are not over. They are continuing and a decision on the launch may be known Wednesday afternoon,” S. Satish, a director at ISRO, told IANS.

An ISRO official told IANS on condition of anonymity: “Tests will be conducted throughout Tuesday night. We will be able to take a call on the rocket launch after going through the test results.”

ISRO Sunday decided to postpone the flight of its rocket geosynchronous satellite launch vehicle (GSLV) after it detected a leak in one of the valves of the Russian-made cryogenic engine.

The leak was detected during the pre-countdown mandatory tests even as the 51-metre tall rocket was on the launch pad at Sriharikota.

The rocket was to carry GSAT-5P, an advanced communications satellite meant to retire an earlier one sent up in 1999 and ensure continuity of telecom, TV and weather services.

On Monday, ISRO officials said some tests would be conducted Tuesday to measure the extent of the valve leak. He said tests and discussions with Russian scientists would go hand in hand at the Sriharikota rocket launch centre, around 80 km from here.

The Russians had supplied seven cryogenic engines, of which five were used in the earlier GSLV rockets.

The 29-hour countdown, planned to commence at 11.01 a.m. Sunday, was not authorised by the Launch Authorisation Board. The board met Sunday forenoon at the Sriharikota rocket launch centre to review the results of pre-countdown checks and decided against proceeding with the mission.

Sources close to ISRO told IANS that there are standard leak rates for valves. Only when this exceeds the minimum level are alarm bells sounded.

ISRO officials said that since the cryogenic engine is supplied by Russia, their expertise and consent will be obtained on how to plug the leak. If at all the valve has to be replaced, then it has to be supplied by the Russians, the sources said.

“The components of Indian cryogenic engine are of varied specifications and will not fit the Russian made one. The Russians had supplied the seven cryogenic engines long ago,” the source told IANS.

According to officials, dismantling of the cryogenic engine with the faulty valve and fitting the rocket with another one will be a tedious affair or even impossible due to its complexity.

According to ISRO officials, a delay in the GSAT-5P launch will not affect any of its customers as the earlier satellite INSAT-2E is still operational.

According to ISRO officials, the GSLV rocket has three stages. The first stage is fired by solid fuel and hugged by four strap-on motors fired by liquid fuel. The strap-on motors give additional thrust during the lift off and the initial phase of the rocket’s flight.

The second stage/engine is fired by liquid fuel and the third and complex stage is the cryogenic engine powered by liquid hydrogen as fuel and liquid oxygen as oxidizer. The solid fuel is cast ready while the liquid fuel is filled barely hours before the rocket’s blast-off.

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