The Indian Space Research Organisation started using space technology early, barely six years after the historic launch of Sputnik in 1957 and two years after Yuri Gagarin's flight into space, thanks to pioneers like Vikram Sarabhai, who realised the potential role of space technology in the nation's development.
India acquired the capability of going to the Moon in 1994 with a successful Polar Satellite Launch Vehicle flight. Still, it was in 1998 that ISRO started looking for new challenges and opportunities and proposed a mission to the Moon. The government sought a feasibility report from the Advisory Committee on Space (ADCOS) and constituted the Moon Mission Task Force. After nearly 50 missions to the Moon by various countries, the most challenging task was to do something scientifically new. After much thought, a Lunar Polar Orbiter was proposed to examine the hitherto unexplored lunar poles, specifically to look for water brought in by impacting comets. The report underwent a series of elaborate review processes; finally, Prime Minister Atal Bihari Vajpayee approved the mission and announced it in his Independence Day speech from Red Fort in 2003. It took five years to build various instruments and the lunar vehicle indigenously, and the mission was launched on October 22, 2008. This mission changed the global outlook of space exploration from an era of competition to collaboration and cooperation by inviting many countries, including the USA and Europe, as guest investigators on board Chandrayaan-1.
The scientific outcome of the Chandrayaan-1 mission has been immense. The three concepts prevalent in the pre-Chandrayaan-1 era, based on various missions and a study of samples, were that the Moon was bone dry, volcanically dead with its volcanic activity having ceased billions of years ago, and it is tectonically inactive. These had to be revised after Chandrayaan-1 discovered enormous amounts of water as ice on the north and south poles. It also noted recent volcanic activity and tectonically unstable areas due to impact induced seismic activity. Water is a miracle molecule. It can yield hydrogen, which can be used for power generation, even to synthesise rocket fuel and generate oxygen, essential for human habitation. Chandrayaan-1 thus shifted the focus of the space community to the lunar poles.
Taking the lead from the importance of lunar poles, in 2019, 11 years after Chandrayaan-1, ISRO embarked on Chandrayan-2, its second mission, with much improved sensors, a lander and a rover to study the chemical and mineral nature of dust in the south pole region. The orbiter has kept working well for all these years, transmitting data and photographing the Moon, but the lander, with the rover in its lap, could not accomplish a soft landing and crashed on the Moon as it approached its destination. No matter how much one anticipates the hurdles and takes care to circumvent all eventualities, failure is an inevitable part of the process. Still, it did not deter ISRO from rectifying the design of the lander and its soft landing strategy, and on July 14 this year, it launched the follow-up mission, Chandrayaan-3.
Chandrayaan-2 orbiter, still working well, provided valuable photographs of the landing site, and it also serves as a communication bridge to the Earth. On August 23, Chandrayaan-3 accomplished its technological goal of soft landing near 70 degrees South at the predesignated site, with picture-perfect descent. All mission components are in good health, so the rover has moved out on the ramp and began its operation on the nearby ground. The lander and rover are equipped with instruments to collect information on mineral and chemical composition, the thermal depth profile of the dust layer, seismic activity, and plasma environment and also carry NASA's retroreflector to accurately estimate the variation of distance of the Moon from the Earth to see if the Moon is slowly receding away from it, a few centimetres every year. Overall, it is a technologically and scientifically well-planned mission. ISRO is now looking forward to 14 days of exciting science as long as the sunlight enables the generation of power required for the instruments.
The renewed interest in exploring the Moon by various space agencies has been motivated by the realisation that the Moon has a vital role in future space exploration. The idea that the Moon can act as a gateway for planetary exploration for missions to other planets is gaining ground. One can send small instruments to many planets directly from the Earth, but the Moon's much lower gravity can be advantageous for sending big, heavy instruments or complex structures. One can assemble devices on the Moon and launch with relatively smaller rockets.
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Secondly, the Earth's atmosphere is now so heavily polluted with chemicals and radiation that the far side of the Moon, protected from their influences, can serve as a much better place for astronomical studies of the cosmos. Also, the near side of the Moon offers an excellent opportunity for a meteorological laboratory to continuously monitor the Earth's weather, atmosphere, oceans and landscape. A futuristic idea of collecting Helium-3 from the lunar dust is also floating because this is the only isotope not found on the Earth. It is formed on the sun, accompanies solar wind and gets implanted in the lunar dust grains. The importance of Helium-3 lies in its potential as a fusion fuel--- a few kilos can provide clean fusion energy for the whole Earth for many years.
Given NASA's ambitious Artemis crewed missions for establishing a permanent base on the Moon and the manned mission planned by Russia, China, Japan and other countries, if ISRO wants to keep pace and play an important role in planetary exploration, three missions (effectively only two, since Chandrayaan-3 only completed the unfinished task of Chandrayan-2) in 15 years, is too few and infrequent. A sustained plan of a mission every 3-4 years will enable ISRO to remain at the forefront of lunar exploration. ISRO must also further strengthen the effective space exploration model it has developed. Since planetary exploration requires serious technical developments and scientific vision and planning, maybe an Institute entirely devoted to planetary sciences and exploration will serve them well in the long term.
(Views are personal)
(nnbhandari@gmail.com)
Dr Narendra Bhandari
Former Chair, Planetary Science and Exploration Program, ISRO