Chandrayaan sensor snag,but mission alive: ISRO

The halo around Indias showcase space mission,Chandrayaan-I,lost a bit of its shine on Friday....

The halo around Indias showcase space mission,Chandrayaan-I,lost a bit of its shine on Friday with the Indian Space Research Organisation (ISRO) revealing that the spacecraft had developed a serious technical snag about two months ago,that had since been fixed to keep the mission alive.

In an official statement,ISRO said the star sensor,used for determining the orientation of the spacecraft on the basis of its distance from stars,had started malfunctioning from the last week of April. The spacecraft needs to be kept at the right orientation so that the cameras and other equipment installed on board are constantly focused on the moons surface. The inability to do so would jeopardise the experiments being carried out from the spacecraft.

To overcome this anomaly,ISRO devised an innovative technique of using redundant sensors gyroscopes along with an antenna pointing information and images of specific locations on the surface of the moon for determining the orientation of the spacecraft, the statement said.

ISRO stressed that all the instruments on board were functioning normally and continuing to send data back to the earth stations as expected.

Mission operations are being carried out satisfactorily. Other than the failure of the star sensor and one of the bus management units,health of the spacecraft is normal, ISRO chairman G Madhavan Nair said at a press conference.

To put it in perspective,Mylswamy Annadurai,project director of Chandrayaan-I,said INSAT-2E,a communication satellite,has been carrying a similar defect for the last nine years but has been functioning normally. Annadurai said ISRO scientists had prepared a contingency plan for this satellite that was very similar to what has been applied in the case of Chandrayaan-I.

Annadurai said more than 90 per cent of the mission objectives had already been realised and an imagery of almost the whole moon had been created.

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Nair stressed that the life of the spacecraft was not dependent on the star sensor. But he did not rule out calling off the mission ahead of schedule since most of its job had been completed.

Chandrayaan-I was launched in October last year,catapulting India into a select league of countries having a lunar space programme. Apart from being the first Indian spacecraft to enter the lunar orbit,Chandrayaan-I captured the imagination of the country by sending the Indian tricolour to the moons surface.