On July 14, at 2:35pm, India’s most powerful launch vehicle, the Launch Vehicle Mk III (LVM3) took off into the clear sky. Over ten thousand enthusiasts packed themselves into the Launch Viewing Gallery at the Satish Dhawan Space Centre, Sriharikota, within a space meant for half that number. The crowd included a large number of schoolkids, some from as far away as Indore, Delhi and Pilani. Cheered on by these ten thousand, and by millions more staring into their screens, the LVM3 lit up the already dazzling sky, as it shot off to the Moon, carrying with it one of India’s most precious consignments – the Chandrayaan-3.

The Chandrayaan-3 is India’s third mission to the Moon, and follows its predecessors Chandrayaan-1 (2009) and Chandrayaan-2 (2019). Follow-up missions usually build on the success of their predecessors. Chandrayaan-3, however, follows a “failure-based design”, designed to accomplish those goals that Chandrayaan-2 failed to achieve.

‘Fly Me To The Moon’

On 15th August 2003, from the ramparts of the Red Fort, Prime Minister A B Vajpayee announced that India would go to the Moon. The Indian Lunar Exploration Programme was born. The Programme consists of four phases, of which the second phase is in progress.

Mission Map – Indian Lunar Exploration Mission

One of the main objectives is to look for water on the Moon. The most likely location for this was the Lunar South Pole, and specifically the Shackleton Crater, an impact crater which, since the 1990s, has been giving indications of containing water ice. Over time, India’s objective is to get samples back from the Moon.

Getting There

Chandrayaan-1 was launched in October 2009. This craft consisted of:  

• A Lunar Orbiter equipped with various scientific instruments such as terrain mapping cameras, X-ray spectrometers and devices to analyse the mineral composition of the lunar regolith (i.e., the “sand” on the Moon).
• The Moon Impact Probe (MIP) to study the Moon’s surface.

Doing the Unprecedented

 The MIP was designed to study the Moon’s surface and to do so, it was intentionally crashed (i.e., a hard landing). This is a legitimate landing method, cruder but simpler, faster and cheaper than a soft landing. While this in itself was (pardon the pun) ground-breaking, the MIP did something far more extraordinary – it found water vapour on the moon!

The Moon has an extremely sparse atmosphere (about 10 trillion times thinner than the Earth’s). It cannot offer protection against radiation, nor can it support flight, and is akin to a vacuum on Earth. But it has long been postulated that there would be water on the Moon, and Chandraya

an-1 had discovered it!

The unprecedented discovery of water on the moon aside, the MIP’s hard-landing was a big milestone too. Up until that point, only the USSR (1959), USA (1962), Japan (1993) and the European Space Agency (2006) had done this. India had even beaten China (2009) to it. 

Phase 1 was complete. The next step was to soft-land on the Moon.

The Touchdown That Wasn’t

Chandrayaan-2 was announced in partnership with Russia in 2007. The mission involved:

• An Orbiter, to study the Moon’s surface remotely.
• A Lander that would perform a soft-landing or a “touchdown”.
• A Rover that would navigate the surface of the Moon.
  

Roscosmos, the Russian Space Agency, was to provide the lander, while ISRO made the orbiter and the rover. Unfortunately, Roscosmos kept delaying the Lander, and ISRO decided to make its own Lander in 2015.

After a lot of rescheduling and one launch abort, Chandrayaan-2 took off aboard India’s newest and most powerful launch vehicle, the LVM-3. The launch happened on 22nd July 2019, on the Golden Jubilee of the Apollo 11 Moon landing. The payload consisted of the Orbiter along with Vikram, the Lander, and Pragyan, the Rover.

While the Orbiter did its job again, the Lander developed issues and was unable to slow down sufficiently enough, and ended up crashing onto the Lunar Surface.

Phase 2 was incomplete.

Criticality of its Success

As part of its Moon Mission, India signed a strategic partnership with Japan in 2018, called the Lunar Polar Exploration Mission (LUPEX). Scheduled to launch in 2025, this craft was to have a Rover designed by JAXA (the Japanese space agency), while ISRO provided the Lander.

With the failure of the Lander in Chandrayaan-2, the timelines for LUPEX was thrown into disarray. It was quintessential for India to demonstrate its landing capabilities. Enter Chandrayaan-3.

‘Failure-Based Design’

In an interview on 10th July 2023, ISRO Chairperson Dr. A Somanath said that the changes in design of the Chandrayaan-3 Lander was built on the lessons learned from the failed landing of Chandrayaan-2. He called it a “failure-based design”. 

Chandrayaan-3 is essentially a tech demonstration mission. It carries very few scientific instruments on its lander and rover, which are almost identical replicas of those on Chandrayaan-2. In fact, they even retain the same names – Vikram and Pragyan. The new additions on the lander include a whole bunch of Landing Sensors to ensure a smooth landing. The Lander also has one thruster lesser than the previous one.

Here is quite a succinct highlighting the differences between Chandrayaan-3 and it’s predecessor.

Getting There

Chandrayaan-3 took off on 14th July 2023. To go to Space, the fastest way out is a powerful rocket that launches straight up to escape the Earth’s gravity. NASA’s Artemis uses this trajectory and gets to the Moon in 4 days. However, this requires a lot of fuel, and Artemis’ launch vehicle SLS costs $2 Billion per launch. ISRO, however, adopts a novel approach to solving this problem. It uses less energy and puts the spacecraft into Low Earth orbit. As the spacecraft reaches its farthest point in its orbit (called apogee), it emits a small thrust of energy to make its orbit bigger. This is repeated at the new apogee, and so on. At one point, the spacecraft is so far away that the next thrust pushes it away from the Earth’s gravity. While this takes much longer (around 40 days to go to the Moon), it also costs much lesser – just under $65 million per launch. Since the craft isn’t carrying humans, time is a luxury.

Once it is in Lunar orbit, Vikram and Pragyan will descend at an appropriate time to the surface of the Moon and potentially redefine the future of space exploration. This is expected to happen on 23rd August.

What Will Happen There?

The landing routine will take place in a few hours. After a successful “touchdown” (i.e., soft-landing), the Lander will open and the Rover, Pragyan, will roll out. Pragyan will then move around the surface and study the regolith at different spots around the crater. This stage is well-explained in this animation from ISRO.

How Long Will It Last?

The Earth rotates every 24 hours, and thus has daylight for around 12 hours. The Moon, however, rotates as fast as it revolves around the Earth. Consequently, its daytime is 14 days long. Since the Rover is solar-powered, it is expected to function only when it has sunlight. After 14 days, during the night-time, the temperature will drop to -130 Degrees Celsius, freezing the power systems. It is unlikely that, when the Sun comes up, the equipment will be able to fire up. So, the mission is designed to be just 14 days long.

What Next?

The success of Chandrayaan-3 will signal the completion of Phase 2. With Lander capabilities established, LUPEX will be in full steam mode. LUPEX, which will potentially be called Chandrayaan-4, will take off from Japan on their launch vehicle. Meanwhile, India will start preparing its own Rover for Chandrayaan-5, to reliably complete Phase 3. All of this is scheduled for this decade.

There are geopolitical and commercial implications associated with the success of this mission. India will be the third country after USSR, USA and China to soft-land on the Moon. This would assert India’s dominance as a Space Power, making it a key player in drafting space policy over the next decades. It might also be the first step to building commercial transport systems to the Moon and deciding the future of space exploration.

All of it depends on the success of Chandrayaan-3, which will be known by the end of August. So, where will you be on Landing Day? What are your plans to celebrate that momentous occasion? Let us know in the comments below! And keep watching this space for the latest news on Chandrayaan 3.