Indian, Russian scientists discuss rocket launch delay

The Indian Space Research Organisation (ISRO) Sunday decided to postpone the rocket’s launch after it detected the leak in one of the valves of the Russian-made cryogenic engine during the pre-countdown mandatory tests even as the 51-metre tall rocket was on the launch pad.

The rocket, called the geosynchronous satellite launch vehicle (GSLV) 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.

S. Satish, a director at ISRO, said: “There is a small team of Russian experts at the rocket port whenever a rocket is flown with their cryogenic engine.”He said 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.

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 hours before the rocket’s blast-off.
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 take time.“The new engine’s systems have to be checked and it will take over a month to make it flight ready,” a source said.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.