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Chandrayaan sensor fails; craft’s life may be reduced

Chandrayaan sensor fails; craft’s life may be reduced
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First Published: Fri, Jul 17 2009. 11 02 AM IST
Updated: Fri, Jul 17 2009. 11 02 AM IST
Bangalore: India’s first moon mission Chandrayaan-I, launched in October last with a two-year life span, has lost a major sensor and may meet a premature end, Isro said on Friday.
“Unfortunately, during the last month we have lost a vital sensor — the star sensor,” Isro chief G Madhavan Nair said.
“Like in the olden days when one used to look at the stars to fix a direction, likewise an onboard electronic equipment was doing all this and it was required for precise pointing (towards the moon). With its loss we are really worried,” he said.
“But to the credit of the Isro scientific team, they have worked out a very innovative way of overcoming the problem,” the Isro chief said, but added that if some more failures happen, “then we will have problems”.
Nair, however, said that in the last eight months of the operation of the mission, “we have collected almost all the data that we wanted” and that most of its objectives have already been completed.
Chandrayaan-I was launched from the spaceport of Sriharikota in Andhra Pradesh on 22 October last year.
Isro spokesperson S Satish said, “We are not sure how long we will be able to sustain it. The life of Chandrayaan-I designed for two years may be reduced”.
He, however, maintained that the mission is not crippled adding, “it is continuing satisfactorily.”
Isro said it has devised innovative technology and is using antenna pointing mechanism and gyroscopes to overcome the problem.
Giving details about the problems encountered by the mission after its launch, Nair said “Space missions are very, very complex. There are instances of problems on board. We were also not spared from these.”
He said that the craft had faced fairly hostile environment around the moon especially in terms of thermal cycling as well as radiation.
“The first thing what we encountered when it was put in the 100 km orbit, it simply reached a stage of thermal runaway. The entire spacecraft would have been baked. We would have lost it,” he said, adding that it was a scenario about a month after the launch.
The ISRO chief said the mission has reached a stage where many of the electronics have failed and indeed some of the power supply instruments have malfunctioned.
“But fortunately, we were able to energise the redundant units and keep them alive all this time. This has been going on for quite sometime. Unfortunately, during the last month we have lost one vital sensor,” he said.
“Chandrayaan can continue but of course one cannot predict....failures can always happen if some more failures happen, then we have problems,” he said, adding that the mission is a “100% success”.
On Chandrayaan-II, Nair said the scientists had to take care of environmentally greater issues.
“As you know we did not have experience of this kind anytime earlier. This is for the first time we have understood the intricacies of going around the moon and this data will help us make the subsequent mission much more reliable,” he said.
The mission objectives of Chandrayaan-I included surveying the lunar surface to produce a complete map of its chemical characteristics and 3-dimension topography.
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First Published: Fri, Jul 17 2009. 11 02 AM IST