India’s Chandrayaan-1 mission, the country’s first effort at deep space exploration, has come to a premature end. Radio contact with the lunar probe was lost 312 days after it travelled into space aboard the Polar Satellite Launch Vehicle. According to the Indian Space Research Organisation (ISRO), data were received from the probe till shortly after midnight on August 29. About an hour later, all communications ceased abruptly. Without these radio links, controlling the spacecraft and getting data from it became impossible. Such an end was, in fact, expected. For much of the spacecraft’s operational life, ISRO chose to convey the impression of a mission that was proceeding smoothly and according to plan. In reality, the probe seems to have been beset virtually from the start by the failure of crucial onboard systems. Both star-sensors used to maintain the spacecraft’s orientation stopped working, as did one of two ‘Bus Management Units’ that performed vital control functions. In addition, thermal management to keep the spacecraft’s systems and instruments from being alternately baked and frozen was not easy. The radiation environment around the Moon turned out to be more hostile than expected. As a result of these problems, ISRO opted in May to move the spacecraft farther away from the Moon. But it was only in July that the space agency finally acknowledged the extent of the setbacks and admitted that the mission was in jeopardy.

Yet these problems make what has been achieved all the more remarkable. It is a tribute to ISRO’s mission management team that they could find ways to keep the spacecraft and its instruments operational for so long. Although the mission has fallen well short of the two years it was expected to last, a great deal of data has been gathered by the Indian and foreign instruments on the spacecraft. In the course of more than 3,400 orbits the probe made around the Moon, its instruments closely scrutinised the lunar surface using various wavelengths of light as well as x-rays and radar. Just 10 days ago, the crippled Chandrayaan-1 ably played its part in a complicated radar-based duet with the recently launched U.S. spacecraft, Lunar Reconnaissance Orbiter. In the months and years ahead, data from the Indian probe will help scientists better understand the Moon’s origin and evolution, its mineral composition, and whether water might lie trapped in its permanently shadowed polar craters. Valuable lessons will no doubt be learnt from the Chandrayaan-1 experience. ISRO will now be better prepared to undertake the Chandrayaan-2 mission which, with Russian involvement, is expected to put a lander and robotic rover on the Moon in a few years’ time. But what India’s upstanding space agency needs to do better next time is square with the public that has given it its steadfast support.


Chandrayaan-1 mission terminatedAugust 30, 2009

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