Dr T K Alex, director, ISRO Satellite Centre, Bangalore, said, "We assumed that the temperature at 100km above the Moon's surface would be around 75 degrees Celsius. However, it was more than 75 degrees and problems started to surface. We had to raise the orbit to 200km."
The thermal issue reportedly appeared in Nov, forcing ISRO to deactivate some payloads. Officials also said scientists had foreseen that the mission would fail before the official announcement made on Aug 25.
However ISRO chief Madhavan Nair said, "The moon mission was a great success and 95 per cent of its objective was completed. We could collect a large volume of data, including 70,000 images of the moon."
According to ISRO director S Satish, Russian and American radars will be used to track Chandrayaan's position and orbit.
"Scientists from the European Space Agency (ESA), the National Aeronautics and Space Administration (NASA) and the Bulgarian Academy of Sciences will review the performance of their payloads (scientific instruments) that were onboard the spacecraft along with our payloads," he said.
"None of the lunar missions has been for more than a year. Many of them last six-seven months whereas our mission lasted for about 10 months against heavy odds, including the hostile lunar environment, solar radiation and other variations in the space," the ISRO director said.