Tarmak007 -- A bold blog on Indian defence: GSLV-MK-III payload fairing completes acoustic tests at NAL | Inter-stages, strap-on boosters next in line for qualification process

Tuesday, March 13, 2012

GSLV-MK-III payload fairing completes acoustic tests at NAL | Inter-stages, strap-on boosters next in line for qualification process

 The GSLV MK-III payload fairing (PLF) undergoes rigorous qualification process for the flight-readiness at the Acoustic Test Facility of NAL in Bangalore. The core team and scientists associated with the project are also seen. Express Photo: Sudhakar Jain
By Anantha Krishnan M
Express News Service
Bangalore: Fifty scientists from Indian Space Research Organisation (ISRO) and National Aerospace Laboratories (NAL) have just completed a critical test on a gigantic piece of history directly linked to India’s GSLV MK-III mission. Sources tell Express that the payload fairing (PLF), also known as the satellite protection system or heat shield, of the GSLV Mk-III has been put through rigorous dynamic qualification by the scientists at the Acoustic Test Facility (ATF) in Belur, near Bangalore. The state-of-the-art ATF is designed and built by NAL along with ISRO, to qualify Indian satellites and launch vehicle subsystems.
The test is aimed at determining the protection of the satellite during lift-off and trans-atmospheric flight. It is being done with a dummy satellite simulating the mass and volume of the actual spacecraft which the GSLV Mk-III is intended to carry. Sources say that the launch vehicle is being designed to put into orbit satellites of 4-plus tones. “It can be a single satellite or a dual one totaling 4 tones. It is for the first time India is attempting the launch of such a massive vehicle,” sources said.
The GSLV MK-III PLF is 11-meters tall and five meters in diameter. During the tests at facility, the PLF -– a massive carbon-fibre reinforced plastic (CFRP) structure -- was subjected to very-high noise levels. The vibration responses on the structure were monitored during the tests to characterize the performance of the heat shield. “Very sensitive instrumentation was used to measure vibration as low as one millionth of a ‘g’. The data collected is extensively analysed to understand the behaviour of the PLF during lift-off and the flight regime,” sources said.
The ATF is now gearing up for further qualification of the GSLV MK-III hardware such as inter-stages and strap-on boosters. “We hope to complete these tests within six months so as to be ready for the scheduled first launch of GSLV MK-II towards 2012 end,” sources said. So far, the ATF has been used to qualify Indian satellites such as IRS series, INSAT series and Chandrayaan, in addition to a few satellites for the European Space Agency.
WHY: Acoustic noise is a fast varying random pressure wave. Rocket blast creates large sound pressures, about 1,00,000 times more powerful than normal speech. This can damage the payload (satellites housed in the uppermost stage of the launch vehicle) and launch vehicle subsystems.
WHAT: An acoustic facility simulates, in a reverberation chamber, the fluctuating sound pressure field experienced by the payload/launch vehicle during lift off and atmospheric flight. The acoustic test is a major dynamic test for qualification of space systems and components.
HOW: The high intensity acoustic noise in the facility is created by modulating a stream of high pressure air using powerful electro-pneumatic transducers. These noise generators are coupled to the reverberation chamber by matched horns.
Copyright@The New Indian Express
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