In a historic achievement for India’s space endeavours, the Chandrayaan-3 lunar rover successfully disembarked from its spacecraft early on August 24, 2023. This significant move marks the commencement of its mission to explore the enigmatic lunar surface, located at the moon’s South Pole. The Indian Space Research Organization (ISRO) delivered the news via the messaging platform X, formerly known as Twitter.
With the mission’s success, India has become the first country to land a spacecraft in uncharted territory near the lunar South Pole. In fact, India is only the fourth country in history to complete a soft landing on the Moon after the United States, the Soviet Union and China.
The successful landing of Chandrayaan-3 on the Moon is one of the most defining moments in India’s history. It consolidates its position as a space power. India is one of the four countries to accomplish a soft landing on the lunar surface, and the first to do so near the Moon’s South Pole. Just like the implications of the nuclear tests, for instance, went far beyond nuclear or military affairs, the ramifications of Chandrayaan-3’s success are not restricted to matters of space. ISRO’s successful mission adds yet another dimension to India’s increasing global heft, across sectors.
This great success in space exploration comes, coincidentally, when Prime Minister Narendra Modi is in Johannesburg, South Africa, for the BRICS (Brazil, Russia, India, China and South Africa) summit. Chandrayaan-3’s success will boost India’s profile and standing among its BRICS partners.
However, India started celebrating on August 23, 2023 itself, when Chandrayaan-3 accomplished a precise landing on the uncharted southern extremity of the moon. This achievement followed Russia’s Luna-25 recent failure, catapulting India into the spotlight as the pioneering nation to accomplish this remarkable feat.
According to the ISRO, the Chandrayaan-3 Rover executed a seamless transition from the Lander, symbolizing India’s tangible presence on the moon’s surface. With an estimated budget of around R 615 crore, this endeavour marked India’s second endeavour to touch down on the moon. The prior attempt, Chandrayaan-2 in 2019, had achieved an orbiter deployment, albeit with an unfortunate crash landing of its lander.
Derived from Hindi and Sanskrit, the term ‘Chandrayaan’ translates to “moon vehicle”. The choice of the lunar South Pole as the mission’s destination stems from its speculated water ice reserves. These resources are anticipated to be crucial for sustaining future space missions by offering essential elements like fuel, oxygen, and drinking water. However, the rough and uneven terrain of the moon’s South Pole adds complexity to the landing process. The historic event captivated millions across the nation, with a staggering 80 lakh viewers tuning in to witness the landing on YouTube’s live stream.
The real test of the mission began at the last leg of the landing. Prior to 20 minutes before landing, ISRO initiated Automatic Landing Sequence (ALS). It enabled Vikram LM to take charge and use its on-board computers and logic to identify a favourable spot and make a soft-landing on the lunar surface.
Experts say that the final 15 to 20 minutes were highly crucial for the success of the mission when Chandrayaan-3’s Vikram lander descended down to its soft landing. Indians throughout the country and across the world are prayed for Chandrayaan-3’s Successful Landing today.
Given the history of India’s second lunar mission, which failed during the last 20 minutes before landing, ISRO was extra-cautious this time in the process. Due to high risk to the spacecraft minutes before moon landing, the duration is dubbed by many as “20 or 17 minutes”. During this phase, the whole process became autonomous, where Vikram lander ignited its own engines at the right times and altitudes.
Chandrayaan-3 consists of an indigenous Lander module (LM), Propulsion module (PM) and a Rover with an objective of developing and demonstrating new technologies required for Inter planetary missions. The Lander will have the capability to soft land at a specified lunar site and deploy the Rover which will carry out in-situ chemical analysis of the lunar surface during the course of its mobility.
The Lander and the Rover have scientific payloads to carry out experiments on the lunar surface. The main function of PM is to carry the LM from launch vehicle injection till final lunar 100 km circular polar orbit and separate the LM from PM. Apart from this, the Propulsion Module also has one scientific payload as a value addition which will be operated post separation of Lander Module. The launcher identified for Chandrayaan-3 is LVM3 M4 which will place the integrated module in an Elliptic Parking Orbit (EPO) of size ~170 x 36500 km.
After rolling down a ramp from the Chandrayaan-3 lander, the six-wheel, 26-kg rover, which is capable of slowly moving up to 500 metres, will begin its job of lunar exploration. The landing has happened at lunar dawn, and the six payloads on board the lander and rover will start collecting data soon after to get as much science as possible in the single lunar day or 14 Earth days for which they will remain operable.
The Chandrayaan-3 payloads will further the science learnings of the two predecessor missions by studying lunar quakes, mineral compositions, and the electrons and ions near the surface of the Moon. The mission will attempt to study water-ice, the presence of which was detected by Chandrayaan-1.
With Chandrayaan-3 successfully landing on the Moon’s surface, decks have been cleared for ISRO to unveil the next stage of its lunar exploration programme. As of now, ISRO is preparing for one more lunar mission, this one in collaboration with Japanese space agency, JAXA. This mission, called LUPEX, or Lunar Polar Exploration, is slated for 2024-25. But there would be more in the Chandrayaan series as well.
Over the next 14 days, the six-wheeled rover will carry out experiments on the surface of the moon. Both Vikram lander and Pragyan rover have a mission life of 1 lunar day, equal to 14 days on earth. The lander module is carrying five payloads for specific tasks on the Moon.
The rover’s an Alpha Particle X-Ray Spectrometer will be used to derive the chemical composition and infer mineralogical composition to further enhance the understanding of the lunar surface. A Laser Induced Breakdown Spectroscope will determine elemental composition of the lunar soil and rocks around the landing site.
The lander is also carrying RAMBHA-LP (Langmuir Probe) to measure the near surface plasma (ions and electrons) density and its changes with time. ChaSTE Chandra’s Surface Thermo Physical Experiment will carry out the measurements of thermal properties of lunar surface near its polar region. The Instrument for Lunar Seismic Activity will measure the seismicity around the landing site.
The Space Applications Centre (SAC) of ISRO and Physical Research Laboratory (PRL) have made crucial contributions to the Chandrayaan-3 mission, which landed close to the unexplored lunar South Pole on Wednesday evening. Both institutions were founded in Ahmedabad by DrVikram Sarabhai, father of India’s space programme.
ISRO SAC played a crucial role in the landing process. It has developed a number of sensors on board the lander, including the hazard detection and avoidance camera and processing algorithm. SAC has developed eight camera systems for the Chandrayaan-3 mission, four of which are on board the lander, and one on the rover. Three other cameras on the lander played a crucial role in the landing.
(The author is a regular columnist and can be mailed at [email protected])
