Fictitious reading in sensors led to abortion: ISRO Chief

Chennai, Jan 20: A 'fictitious reading' in two sensors in the Onboard Advanced Mission Computer had led to the abortion of the full duration test of the indigenously developed Cryogenic stage at Mahendragiri.

Indian Space Research Organisation (ISRO) Chairman G Madhavan Nair told UNI today that the sensors assigned for reading pressure and temperature in the Liquid Hydrogen Passage of the Thrust Chamber of the engine, were in the open mode and gave fictitious reading yesterday.

''The sensors, which should have been in the closed mode, gave a false reading that the pressure in the passage came down, and the temperature went up,'' he said.

On sensing the reading, the onboard Advanced Mission Computer, developed by the Thiruvananthapuram-based Vikram Sarabhai Space Centre (VSSC), automatically aborted the mission, giving a sigh of relief to the ISRO scientists at the Liquid Propulsion Systems Centre (LPSC).

''There was nothing wrong and nothing alarming. It's only a minor flaw and we will set it right'', he added.

Mr Madhavan Nair said there was problem in the cryogenic engine. ''We have monitored all the parameters''. Asked on what went wrong, he said there were large number of sensors and the scientists would find out why the two sensors were in open mode. ''There was nothing alarming. We will set right the anomaly'', he said.

On when ISRO would undertake the full duration test, he said ''we will take stock of the availability of fuels, including Liquid Oxygen, Liquid Hydrogen and Liquid Nitrogen''.

''We will do it as early as possible'', he added.

Meanwhile, ISRO sources said there was no leak of propellants as initially suspected to be the reasons for the reduction in pressure and the increase in temperature.

Soon after the abortive mission, scientists worked all through the night to drain out the propellants and warmed up the stage to make it amenable to human access.

''The draining out process has been completed this morning'', ISRO sources told UNI