Bangalore: July 18, 2009 - India’s space agency on Friday insisted that the lunar mission is on track despite a major technical snag, but the belated announcement  has raised serious questions about the Indian Space Research Organisation’s (ISRO) transparency in dealing with the issue.

The failure of a vital sensor that controls the spacecraft was detected over two months ago, but ISRO chose not to reveal the news to an Indian public that has been closely watching the mission much before Chandrayaan-1 was launched on October 22. Even the European Space Agency (ESA), which is a partner in the mission, heard about malfunctioning of the ‘star sensor’ only “a few days ago”, an ESA official said. “I think they could have told the public and the scientific community much earlier,” said Detlef Koschny, ESA’s co-ordinator for the mission. The European agency has three of its instruments riding on the spacecraft.

He reasoned that the delay could have been because ISRO has no previous experience of such a mission and that officials of the agency might have been busy. “I am following what is happening with interest and fear,” he observed.
ISRO raised the orbit of the spacecraft to 200 km from 100 km on May 19, three days after the sensor failed. The official reason for the move, provided on May 20, was that the higher orbit would “enable further studies on orbit perturbations, gravitational field variation of the Moon and also enable imaging lunar surface with a wider swath”.

But it has now become clear that the problems faced by the spacecraft began when it entered its orbital home of 100 km over the lunar surface in November.

Sudden overheating — a rise in Chandrayaan-1’s temperature to over 50 degrees Celsius — prompted ISRO to switch off most of the 11 instruments it was carrying. The star sensor, unable to bear the heat, collapsed.

The ISRO chairman defended the space agency’s transparency, “We can’t share everyday problems. Space programmes will not have only one problem. We have to judge based on how critical the problem is”. M Krishnaswamy, programme director for remote sensing satellites, said foreign partners were informed about the technical snag immediately after it happened. “Foreign partners are happy with the mission. But I don’t have any answer why this information was not revealed to the public.”

Both Mr Nair and Mr Krishnaswamy said they were totally satisfied with the volume and quality of data received from the spacecraft. But aerospace scientist Roddam Narasimha said it was likely that the accuracy of information, especially the resolution of images, could be affected. “Through offline processing of data, it is possible to overcome any quality problems,” he added. ESA’s Mr Koschny said “we have to trust our technical colleagues... I’m confident that the mission can go on for the full two years”.

The spacecraft is now being maintained at an orbit of 200 km by using gyroscopes and calculating its position based on images taken from the orbiter. The Chandrayaan-1 spacecraft carried 11 instruments as cargo, including a ‘moon impact probe’ that was crashed onto the lunar surface in November. The Indian payloads are designed to gather information about minerals on the moon, prepare an elevation map of earth’s natural satellite and identify possible water or ice deposits.

One of the key objectives of the moon mission is to identify deposits of the mineral helium-3. Believed to be abundant on the moon, the non-radioactive helium-3 is regarded as having the potential to power future nuclear fusion reactors for hundreds of years.

The spacecraft was propelled on the 4-lakh-km voyage to the moon in a number of stages, with its orbit being raised progressively by activating its liquid motor. It entered the orbit of moon on November 8.