As Chandrayaan-3 lands on the Moon, the history of ISRO’s remarkable space voyage

ISRO’s satellite programmes

The launch of the Aryabhata satellite on April 19, 1975, marked India’s entry into the space era. Built to conduct experiments in X-ray astronomy, aeronomics, and solar physics, the 360 kg spacecraft was entirely designed and fabricated by ISRO. Prime Minister Indira Gandhi named it after the legendary fifth-century mathematician and astronomer, choosing Aryabhata ahead of ‘Mitra’, to signify the friendship between the Soviet Union and India, and ‘Jawahar’.

The satellite took off from the Kapustin Yar launch base in the Soviet Union on the country’s Kosmas 3M rocket. India didn’t have its own launch vehicle at the time, and the Soviets had in 1971 offered to assist in launching India’s first satellite and later agreed to do so free of cost. The satellite worked well for about five days in space but then lost power, resulting in a loss of communication.

“Aryabhata became the forerunner of our space programme and provided us confidence to build state-of-the-art application satellites for communication, remote sensing of natural resources and meteorological investigations,” U R Rao, who led the development of ISRO’s satellite programme, wrote in ‘From Fishing Hamlet to Red Planet: India’s Space Journey’, a book written by former ISRO scientists.

Soon after Aryabhata, two experimental remote-sensing satellites went into Space: Bhaskar-1 in 1979 and Bhaskar-2 in 1981. These spacecraft laid the foundations for the Indian Remote Sensing (IRS) Satellite system — a series of Earth Observation spacecraft built by ISRO.

It was kickstarted with the launch of the IRS-1A into a polar sun-synchronous orbit (spacecraft here are synchronised to always be in the same ‘fixed’ position relative to the Sun) from the Baikonur Cosmodrome launch pad in Kazakhstan on March 17, 1988.

IRS-1A carried two cameras, LISS-I and LISS-II, which made it the first Indian spacecraft to provide imagery for various land-based applications, such as agriculture, forestry, geology, and disaster management.

In the following decades, a number of IRS satellites were launched and today, India has one of the largest constellations of remote sensing satellites in operation.

Also in 1981, another Indian spacecraft was launched — an experimental communication satellite called Ariane Passenger Payload Experiment (APPLE), which helped inspire the Indian National Satellite System (INSAT), a series of multipurpose geostationary satellites that aimed to meet the telecommunications, broadcasting, meteorology, and search and rescue needs of India.

Although the first few INSATs were built by Ford Aerospace in the US, starting with the INSAT-2 series, all satellites of the system have been indigenously made. The first INSAT-2 spacecraft, the INSAT-2A was the first multipurpose satellite of India. It was launched on July 10, 1992.

“INSAT initiated a communication revolution in the country by providing nationwide connectivity, broadcasting and meteorological information to the most remote corners of the country. Remote sensing satellites have become the backbone for nationwide monitoring of forests, wasteland, environment, water resources, agriculture, ocean, fisheries, cyclones, floods and disasters,” Rao wrote.

Since then, numerous INSAT satellites have arrived in space. The launch of KALPANA-1 in 2002 marked a milestone — it was the first in the series of exclusive meteorological satellites built by ISRO.

More recently, a notable satellite mission has been the Indian Regional Navigation Satellite System (IRNSS) or NavIC (Navigation with Indian Constellation). It began with the launch of India’s first dedicated navigation satellite IRNSS-1A on July 1, 2013, and currently consists of seven such spacecraft. They are used in terrestrial, aerial, and marine transportation, location-based services, personal mobility, resource monitoring, surveying, scientific research, etc.

Launch vehicle programmes

India had been thinking of rockets even before ISRO was established. On November 21, 1963, it launched the US Nike Apache ‘sounding rocket’ from Thumba, near Thiruvananthapuram. The rocket was taken to the launch site on a bullock cart. Sounding rockets are suborbital rockets that carry experiments to the upper atmosphere of the Earth. They aren’t capable of exiting the planet’s gravity or reaching into space.

The first Indian launch vehicle to arrive there was the SVL-3 in 1980. The mission was led by A P J Abdul Kalam, who had joined ISRO in 1969, and was responsible for designing, developing and launching the vehicle. But the success didn’t come instantly as the first attempt to send the SVL-3 into space on August 10, 1979, ended in failure.

The SLV-3 rocket carrying the Rohini-2 Satellite on its way to orbit after it was successfully launched at the Sriharikota Range (SHAR) on April 17,1983. (Express archive photo)

Scientist Ramabhadran Aravamudan in his book, ‘ISRO: A Personal History’, writes about the incident as follows: “The burning of the first stage seemed normal. I was watching Kalam for some sign. Had the rocket performed well? After some time, I saw a blank and fixed expression on his face, followed by disappointment. He turned around and made a thumbs down gesture. Something had gone wrong.”

SVL-3 had gone out of control and splashed into the Bay of Bengal at a distance of 560 km from the coast, about five minutes after take-off from the Sriharikota launch pad.

Kalam and his team learnt quickly from the mistakes. The second attempt for the launch was scheduled for just a year later, on July 18, 1980. There was some tension because Sanjay Gandhi, the Prime Minister’s son, had died in a plane crash about three weeks ago. “Delhi was in chaos as Indira Gandhi tried to come to terms with the loss. In Trivandrum and SHAR this had a trickledown effect, but we were determined to go ahead with our launch,” Ramabhadran wrote.

SLV-3 took off without any glitches, and placed its payload, Rohini 1, a 40 kg experimental satellite, in space. This made India the sixth member of the exclusive club of space-faring nations, and boosted ISRO’s morale to new heights.

SLV-3’s payload capability wasn’t significant. But it provided a learning platform to ISRO, and led to the development of the Augmented Satellite Launch Vehicle (ASLV). This was essentially the SLV-3 rocket, but with additional strap-on boosters, which enabled it to carry a payload of more than 100 kg.

However, ASLV didn’t prove very successful. Its first two launches ended in failure and by the time its first glitch-free take-off came in 1992, a new generation of launch vehicle had made its entry. It was the Polar Satellite Launch Vehicle (PSLV).

PSLV’s development started in 1982, and its maiden successful launch took place in October 1994. Most significantly, it marked India’s entry into the Big Rockets league, as it could carry a payload of up to 1,000 kg.

In the years that followed, PSLV emerged as one of the most reliable and versatile workhorse launch vehicles, sending numerous Indian and foreign customer satellites into space. Some of India’s most ambitious space missions have been launched using this rocket — Chandrayaan-1 rode a PSLV rocket in 2008, as did Mangalyaan, the Mars Orbiter mission, in 2013. PSLV also helped India enter the arena of satellite navigation, which is considered crucial for both civilian and defence applications.

“Today, PSLV is available in three configurations: the generic PSLV with six strap-ons, the core alone (PSLV-CA) configuration with no strap-ons and the most powerful one designated as PSLV-XL, with extended strapons,” scientist N Narayanamoorthy, who was associated with the PSLV project from the beginning, wrote in ‘From Fishing Hamlet to Red Planet: India’s Space Journey’.

The next and latest class of rockets is the Geosynchronous Satellite Launch Vehicle (GSLV). The new launch vehicle primarily aimed to solve two of the biggest limitations of PSLV: it can deliver a payload of about 1,750 kg to a lower Earth orbit, up to an altitude of 600 km from the Earth’s surface; and it can go a few hundred kilometres higher in Geostationary Transfer Orbit (GTO), though only with a reduced payload.

Unlike their predecessor vehicles, GSLVs use cryogenic engines — they consist of liquid hydrogen and liquid oxygen — that provide far greater thrust than the engines used in the older launch vehicles. ISRO developed these cryogenic engines indigenously after the US refused to transfer the technology to India in the 1990s.

The big success came in December 2014, with the experimental flight of the third generation (Mk-III) GSLV, now known as Launch Vehicle Mark-3, containing an indigenous cryogenic engine. The rocket can put a 4,000 kg payload into geostationary orbits that are over 30,000 km from Earth — it is ISRO’s heaviest launch vehicle right now. LVM-3’s first successful mission was in 2017, when it carried the GSAT-19 satellite, a communication spacecraft, into space.

Subsequently, the same launch vehicle put the Chandrayaan-2, weighing 3,850 kg, outside the Earth’s atmosphere in 2019. And last month, it was LVM-3 that took Chandrayaan-3 into space.

PLANETARY EXPLORATION

In the first four decades since its inception, ISRO largely focused on space missions that benefited India in some way or the other. However, with the turn of the century, it began to explore new avenues as it had achieved most of the goals laid out by Vikram Sarabhai, the first chairman of ISRO, including self-reliance, launch capabilities, and societal needs.

“One such mission which apparently had no ‘practical benefits’ was Chandrayaan-1, India’s maiden Moon shot,” the book, ‘From Fishing Hamlet to Red Planet: India’s Space Journey’, mentions.

The notes that it took ISRO more than four years to convince the Indian government to greenlight the mission. Former ISRO chairman K Kasturirangan, in a 2006 lecture, said, “We had to go through an elaborate process of consultation and justification with the scientific community, academics, the political system and the public media before the mission was given the go-ahead… This process, spread out over four years, culminated in the announcement by the Prime Minister of India (Atal Bihari Vajpayee) on 15 August 2003 on the nation’s decision to enter the new era of planetary exploration.”

With the approval of the Chandrayaan-1, an Orbiter mission, ISRO began preparations, aiming to launch in 2008. It improved the payload capabilities of the PSLV, which was ISRO’s main rocket at the time, and realised that it had some excess capacity. “It was then proposed that we could invite foreign space agencies to send their instruments on our mission,” G Madhavan Nair, who was the space agency’s chairman between 2003 and 2009, told The Indian Express recently. The Chandrayaan-1 featured payloads from international space agencies like the European Space Agency and the US National Aeronautics and Space Administration (NASA).

The Chandrayaan-1 mission was launched on October 22, 2008, and the spacecraft entered lunar orbit on November 8. Six days later, the Moon Impact Probe, which had the Indian colours on its sides, was made to crash land on the lunar surface — to leave India’s mark on the Moon. With this, ISRO became the fifth country to reach the lunar surface. Chandrayaan-1’s orbiter also detected evidence of water on the Moon.

The next milestone for ISRO came on September 24, 2013, with the launch of Mangalyaan — the space agency’s first interplanetary mission. ISRO was the only fourth agency to reach the Mars orbit after Russia’s Roscosmos, NASA, and ESA. The mission was a “technology demonstrator” project to develop the technologies for designing, planning, managing, and operations of an interplanetary mission.

Six years later, the sequel to the first Chandrayaan mission came out. Speaking to The Indian Express, Nair said the discussions for Chandrayaan-2, which would also feature a lander and rover, had started right after the success of its prequel. But its launch came only after Mangalyaan as “there were huge technological learnings involved, particularly with regard to the descent module that was supposed to land”, which took a number of years.

Chandrayaan-2 began its journey to the Moon on July 22, 2019. Its lander, called Vikram, was scheduled to make a soft-landing on the lunar surface on September 7 but minutes before the scheduled touchdown, ISRO lost contact with the spacecraft. Vikram failed to reduce its velocity to an optimal level to ensure a soft-landing, and crashed into the lunar surface.

Despite the lander’s failure, it wasn’t as if the mission itself was a failure. The Chandrayaan-2 orbiter continued to work fine and in the following years, it gathered a wealth of new information that has expanded knowledge about the Moon and its environment.

Chandrayaan-3, launched on July 14, 2023, has now accomplished what the Chandrayaan-2 couldn’t. The success of the mission is not only a major step forward for India’s lunar programme but also showcases its capabilities and scientific advancement.