A lost mission

Back then,things were going like clockwork or “precise to the second” as the ISRO chairman described the flight of the MIP from Chandrayaan-1 to the surface of the moon. In those heady days of the mission,the only note of discord was struck by an unofficial report coming out of China,alleging a mismatch between the data on Chandrayaan’s orbit put out by ISRO and that analysed by private experts in China. No space agency whetted the Internet analysis and despite a few technical glitches causing concerns,till August 29 this year India’s maiden moon mission seemed like it could weather on to orbit the moon for a record 24 months—longer than the Chinese Chang’e 1 spacecraft’s 16-month spin that ended in March this year.

Abrupt end

When ISRO announced loss of all radio contact with Chandrayaan-1 on August 29 and then called off the mission a day later on August 30,scientists involved with the project admitted there was a tinge of disappointment,but in the overall analysis the maiden mission had thrown up more positives than failures,they said.

There were positives even to the early end to the mission. An anonymous commentator on the Internet wrote,“I am happy that the communications failed. When ISRO sends humans to space,communications should be fail proof.”

“It would have been a good record for a first-time mission if Chandrayaan-1 had gone on for two years. Generally these missions are not long. Still,the data received is decent and if the mission had gone on,there would have been more of the same data,” says the director of the ISRO telemetry,command and control (ISTRAC) network,S.K. Shivakumar,who was responsible for controlling Chandrayaan-1 from the earth.

What caused the premature technical termination of the mission is not clear yet,and ISRO insists only detailed analysis can tell conclusively.

Lessons learnt

A miscalculation of the lunar heat radiation environment has been admitted by ISRO as being one of the factors in the early demise of the mission. The radiation began taking its toll when Chandrayaan-1 moved into a 100-km orbit from the moon barely a month after the launch and the spacecraft began overheating and ISRO had to resort to measures like re-orienting the spacecraft to control temperatures,according to Madhavan Nair.

While the spacecraft soldiered on for a further eight months despite the early radiation shock,the break in communication is said to have come with the failure of a backup power management unit that had been operating after the main unit failed early.

“In the initial phase,Chandrayaan-1 was very close to the moon and as it was circling the moon the temperatures became very high. The instruments were reaching their limits of functioning and some of the power-related regulators also faced problems. We had to re-orient the spacecraft to control temperatures,” says Nair.

The experience with the radiation environment of the moon is among the key lessons learnt from the maiden mission to the moon. “We have experience of using instruments in the low earth orbit for many years,but when it comes to the lunar environment,the thermal cycles and radiation temperatures were much beyond our anticipated values. We now have a better idea as to the radiation and other related parameters and this can go towards improving the electronics systems planned for future deep space missions. In the design of Chandrayaan-2,all these factors will be taken into account,” says Nair.

According to the ISTRAC director,analysis of ground systems following the communication breakdown indicated nothing that could have gone wrong. “We need to work out possible causes for the failure on board the spacecraft,” Shivakumar said.

The success story

Besides the low cost of the mission—one-fourth the cost of other moon missions-Chandrayaan-1 has notched other positives. Right at the top of the successes scripted through the mission is India’s entry into the league of countries—the US,Russia,the European space group,Japan and China—who have sent indigenous deep space missions to the moon.

Having missed out on the first phase of exploration of the moon that was dominated by the US and Russia,the maiden Indian moon mission came in the middle of a return to the moon by space-faring nations and marked a coming of age of low-cost indigenous technology.

Chandrayaan-1 was preceded by the Japanese mission Celene and the Chinese Chang’e 1 and was followed by the US Lunar Reconnaisance Orbiter that was launched on June 19 this year. A Russian mission and India’s own Chandrayaan-2 are in the pipeline as the moon is being studied more thoroughly for mineral and energy sources.

Chandrayaan-1 also marked a new chapter in Indian space collaborations,especially with the United States. Following a special agreement signed with NASA in May 2006,ISRO carried a moon mineralogy mapper and a miniature imaging radar instrument from US laboratories as part of the 11 scientific instruments on Chandrayaan-1.

On the mission side,ISRO executed a flawless launch of the spacecraft into near-earth orbit aboard its workhorse PSLV launch vehicle and then went on to achieve success in its first-ever foray into deep space by inserting Chandrayaan-1 in the lunar orbit 386,000 km from the earth,at a 100-km distance from the moon.

“ISRO’s biggest achievement during the Chandrayaan-1 mission was in taking the spacecraft nearly four lakh km across space,performing complex manoeuvres and an accurate insertion of the spacecraft into the lunar orbit. We also stuck to time schedules in the preparation for the project while coordinating with multiple space agencies,” says ISRO Director for Public Relations S. Satish.

According to Shivakumar,who helped established the first Indian Deep Space Network to track and send commands to Chandrayaan-1 during its journey in deep space,“the systematic setting up of instruments and getting them to work,receiving and storing the scientific data for use by scientists have all been successful”. “The mission was not a flash in the pan. It was nearly perfect. Everyone worked like a team,” he says.

The findings

While the scientific data is yet to be fully analysed,ISRO officials and participating scientists have already shown excitement about the data collected by the 11 instruments from India,USA and Europe.

“The data may not be have been collected to the full extent,but it is quality data and participating scientists are expected to publish results that will provide new insights on the moon over the next six months to three years,” say ISRO officials.

The science manager at the NASA-supported spectroscopy facility at Brown University in the US,Carle Pieters,reported at a conference in Goa recently that the Chandrayaan’s moon mineralogy mapper (M3) confirmed that the moon was once completely molten.

Senior scientist at the ISRO Space Application Centre Prakash Chauhan reported at the same conference that three-dimensional imaging of the moon’s surface with a Terrain Mapping Camera (TMC) had given images of the landing site of the US Apollo 15 mission and tracks of lunar rovers used by astronauts on the lunar surface 40 years ago. The findings proved that the fourth US moon mission was not a hoax,he said.

According to Madhavan Nair,there is,however,no conclusive evidence yet of water on the moon.

“The instruments have yielded quite a few results. But most of them are yet to be examined,so it is a little premature to comment on the scientific achievements of the mission. Detailed studies are on. The mission has captured some wonderful pictures of the moon,” says former chairman of ISRO Prof U.R. Rao.

“Until now,we had only theoretical knowledge of deep space missions. Chandrayaan-1 has provided a better understanding of the lunar environment,” says Satish.

A meeting of all the collaborating scientists on the Chandrayaan-1 mission was held on September 7-8 to discuss mission findings and the way forward for science data received from Chandrayaan-1.

Imaging of the moon’s surface has also thrown up data regarding the best sites to land a rover that will be carried on India’s next,more sophisticated moon mission Chandrayaan-2,tentatively scheduled for 2012-13.