Tracing ISRO’s space exploration missions

From the editor’s desk

By Rabindra Mukherjee

When Chandrayaan-3 lander succeeded in making the softlanding on the surface of the moon recently, the Indian Space Research Organisation(ISRO) entered the league of premier space agencies in the world. India became the first country in the world to land close to the moon's South Pole, a feat that would take Indian space exploration to a new level altogether in the years to come. The whole nation and Indian diaspora everywhere erupted in joyous celebrations after India became the fourth nation in history to land on the lunar surface, after the US, former USSR, and China. It was quite a bold decision on the part of the Indian space scientists to decide to land on the dark side of the moon where no man had gone before, especially after the unsuccessful attempt by Chandrayaan-2 in 2019 to land on the moon’s surface. This shows the kind of confidence Indian scientists have on their ability, as also the support they got from the Modi government. Normally governments would be wary of funding another similar project once a previous one had failed in its mission. But it goes to the credit of the Modi government that it kept boosting the scientists to prepare themselves for the next Chandrayaan mission undeterred by what had happened before. And ISRO must be commended for the good work they have done this time, and in taking all possible measures and safeguards to ensure this Chandrayaan mission does not disappoint the Indians wherever they may be in the world. In an effort to understand the trajectory of ISRO’s elevation to this premier status, a peep into its history briefly may be of immense help to those who now look upon this institution with respect and admiration. Scientists come and go, but their legacy accumulates and remains intact in the very institution they nurture throughout their respective tenures while working for the institution. ISRO’s notable milestones can be studied under three categories: satellites, launch vehicles, and planetary exploration.

It all began for ISRO with the launching of the Aryabhata satellite in 1975 to conduct experiments in X-ray astronomy, aeronomics, and solar physics. The 360 kg spacecraft Aryabhata was entirely designed and fabricated by ISRO. The erstwhile USSR offered to launch the satellite for the Indians free of cost, and it did so, though Aryabhata remained operational for only about five days in space and then lost power which resulted in a loss of communication. Then the two experimental remote-sensing satellites - Bhaskar-1 and Bhaskar-2 were sent into space in 1979 and 1981, respectively. These satellites were followed by the launch of the IRS-1A into a polar sun-synchronous orbit in 1988.

After that the era of INSATs came in 1992. Initially it was built in the US and then the subsequent INSATs were indigenously built in India. The launch of KALPANA-1 in 2002 ushered in an era of ISRO-built exclusive meteorological satellites.

Since India did not have a viable launch vehicle programme, this was precisely what ISRO’s scientists wanted to kick-start without much delay. The first Indian launch vehicle to arrive on the scene was the SVL-3 in 1980. The previous attempt to send the SVL-3 into space in 1979 had proved to be a failure. Since SLV-3’s payload capability wasn’t much, to say the least, the next development in the series was that of the Augmented Satellite Launch Vehicle (ASLV). But ASLV also did not prove successful, necessitating a new generation of launch vehicles called the Polar Satellite Launch Vehicle (PSLV). PSLV proved to be the most reliable launch vehicle at that time, sending many Indian and foreign satellites into space, including Chandrayaan-1 in 2008, and Mangalyaan, the Mars Orbiter Mission, in 2013. But technology does not remain static and launch vehicle technology was no exception. The next classes of rockets that have entered the scene are the Geosynchronous Satellite Launch Vehicle (GSLV). GSLVs use a better technology, unlike the previous classes of rockets. It uses cryogenic engines which use liquid hydrogen and liquid oxygen. This technology helps in providing greater thrust to the engines than the previous engines in use. Interestingly, ISRO was left with no choice but to develop cryogenic engines indigenously after the US decided not to transfer the technology to India in the 1990s. So it must go as a tribute to Indian space scientists, for they rose to the occasion and built cryogenic engines within the country itself. Using the cryogenic engine technology ISRO’s heaviest launch vehicle LVM-3 accomplished its first successful mission in 2017, when it carried the communication satellite GSAT-19 satellite into space. Incidentally, this launch vehicle carried Chandrayaan-2, weighing 3,850 kg, to space in 2019. LVM-3 also has the distinction of taking Chandrayaan-3 into space recently, a mission that has proved successful so far.

Following the building of a strong infrastructure that ISRO has done, the focus naturally shifted to more ambitious projects. Space exploration is of immense interest to most countries and India does not want to lag behind in this endeavour.

The stories of space missions and explorations are always very interesting from the perspective of the expectations they carry with them. In the initial years of ISRO, space missions catered only to fulfil direct benefits to India.

But as India gained confidence in its space programmes, it became ambitious. Chandrayaan-1 was India’s first attempt to reach the moon. The Chandrayaan-1 mission was launched on October 22, 2008, which entered the lunar orbit on November 8. After six days, the Moon Impact Probe, carrying Indian colours on its sides, crash-landed on the moon’s surface making India the fifth country in the world to have reached the surface of the moon. Significantly, the orbiter of Chandrayaan-1 found evidence of water on the moon.

The real breakthrough for ISRO came in 2013, when it launched Mangalyaan successfully reaching the milestone of becoming the fourth space agency in the world to reach the mars orbit after Russia’s Roscosmos, NASA, and ESA. The mission proved successful despite a shoestring budget. Following Mangalyaan’s success, which gave a tremendous boost to ISRO’s confidence, the Indian space agency was pretty much upbeat about its Chandrayaan-2 mission. Chandrayaan-2 began its lunar journey on July 22, 2019. Much was expected of its lander, Vikram, which was planned to make a soft-landing on the moon’s surface on September 7. But as is now known, minutes before the planned touchdown, ISRO lost contact with the spacecraft. Vikram could not reduce its speed and instead of soft-landing it crashed into the lunar surface. Though Vikram had failed to accomplish softlanding, the Chandrayaan-2 orbiter continued to work without any glitches and gathered a lot of new information about the environment on the moon. Now that Chandrayaan-3 has accomplished soft-landing on the moon and that too on the difficult dark side near the moon's South Pole, India is assured of its scientific capabilities. Chandrayaan-3 is just the beginning as ISRO has many other plans to accomplish through its space missions. India has been preparing to send its first astronaut mission, which is being called Gaganyaan. This mission aims to send three Indian astronauts to space on India’s own spacecraft. However, ISRO has so far not announced any date to launch the mission. But ISRO is launching its solar observatory Aditya-L1 early next month. This mission will be followed by an earth observation satellite, which has been built in collaboration with NASA. ISRO has also plans to follow up on its Mars orbiter mission, which has concluded recently. In fact ISRO chief S Somnath is confident that India will land on Mars, Venus and other planets, even on asteroids, if it is possible. The successful moon mission is just the beginning.