India achieved a historic first by landing the Lander Module (LM) of Chandrayaan 3 on the rough, cold (temperatures can go down to minus 230 degrees centigrade) and dark terrain of the South Pole of the Moon. A distance of 388,545 kilometres from Earth.
The breathtaking visuals of the LM of Chandrayaan 3 landing safely on the Moon, will now be ingrained in the minds of Indians and all viewers on Earth for years to come.
There was unbelievable thrill and excitement amongst Indians and people all over the world as ISRO’s (Indian Space Research Organization) scientists performed this difficult feat delicately handling the craft to a safe touchdown.
The crash (August 20, 2023) of the Russian Luna 25 due to an unexpected “emergency” disrupting the landing manoeuvre naturally cast a shadow on the Indian Mission with people praying that it would not face a similar fate.
The Luna 25 even though launched on August 10, 2023, much after Chandrayaan 3 on a much lighter and more powerful spacecraft reached lunar orbit earlier. Had it touched down on Moon it would have made Russia the first country to reach the South Pole of the Moon just a few days before Chandrayaan. However, it was not to be.
Even though ISRO officially said that there was no space race between India and Russia, following the Luna 25 crash, everyone had their fingers crossed for the success of the Chandrayaan mission.
ISRO expressed its shock and felt that the Luna crash was “unfortunate”.
India’s Chandrayaan 2 earlier had been a failed mission in 2019 having crashed on the surface of the Moon. Chandrayan 3’s success was therefore keenly awaited by everyone with bated breath.
India is now one among the elite set of countries
Even a soft landing on the moon is no mean feat and places India amongst the only four countries in the world that have shown to have the capability of being successfully able to put their spacecraft on the Moon. India is now one among the elite set of countries like the United States, China and the former USSR.
With this success, India entered the exclusive USD 500 billion space market. The present Chandrayan 3 mission is supposed to have cost an estimated Rs 615 crores which is considered extremely cost-effective for this kind of achievement.
Now India has demonstrated its technological expertise in landing on the Moon. Other countries like Israel, Japan and the United Arab Emirates had all earlier attempted to do a soft landing on the Moon but failed.
The last stretch of ISRO’s successful landing was watched by scientists of America’s National Aeronautics and Space Administration (NASA) and the European Space Agency who had been carefully monitoring the spacecraft’s health and movements during its entire journey and providing regular inputs to the ISRO through their ground stations.
ISRO has been monitoring the health of the spacecraft continuously from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking, and Command Network (ISTRAC), the Indian Deep Space Network (IDSN) antenna at Byalalu, near Bengaluru, with the support from ESA and JPL Deep space antenna of NASA.
ISRO clearly had not been perturbed in any fashion by the crash of Luna 25 and calmly continued in its plan in a steady manner to land its craft on the Moon on its scheduled time of August 23.
Why was south pole of the Moon selected?
The south pole of the Moon is attracting Space agencies of different nations including the US and China because it is supposed to contain ice and water which would be required for any future human settlement or long-term base if it is to be established on the Moon for future inter-planetary explorations. Hydrogen from the ice could be used to make rocket fuel and human inhabitants could use the water itself after it’s treated.
Long stays would be needed when Man would conduct mining activities on the Moon for its rich resources. Interestingly, the presence of ice on the Moon was confirmed in 2008 by Chandrayaan 1 with the help of a US instrument.
This time the six-wheeled rover will conduct experiments on the South Pole of the Moon for a single Moon day or 14 days.
Not only soft landing but ISRO demonstrating its capability to lower a rover (Pragyan) from the Lander Module to perform scientific experiments shows ISRO’s end-to-end capability and technological expertise in both safe landing and roving on the Lunar surface.
Journey of Chandrayaan 3
Chandrayaan-3 had taken off from ISRO’s Satish Dhawan Space Centre (SDCC) in Andhra Pradesh’s Sriharikota on July 14.
The Lander stationed on the Moon’s surface has payloads like Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure the thermal conductivity and temperature; Instrument for Lunar Seismic Activity (ILSA) for measuring the seismicity around the landing site; Langmuir Probe (LP) to estimate the plasma density and its variations. A passive Laser Retroreflector Array from NASA is accommodated for lunar laser ranging studies.
The Rover with wheels which was lowered from the Lander to move on the moon’s surface will have payloads like Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS) for learning about the chemical composition and elements available on the surface of the landing site.
The Propulsion Module which remains in the Moon’s orbit has an attached payload known as the Spectro-polarimetry of Habitable Planet Earth (SHAPE), to study light by taking Earth’s spectral and polarimetric measurements from the moon’s orbit.
Now NASA plans through its Artemis program to have a crew fly by the Moon next year and more importantly have a crew land on the Moon in 2025. The high point of that is that it may carry the first woman astronaut to stride on the moon.
Chandrayaan 3 was not a direct ‘send a rocket to the Moon’ as many people believe. The nearly 40-day journey to the moon actually had three distinct phases once the Chandrayaan spacecraft was separated from its rocket in the earth orbit it took five orbits around the earth.
In each Orbit, its distance from the Earth was increased and in its final orbit, it almost reached a lunar transfer trajectory coming closer to the Moon.
Chandrayaan-3 was then inserted into lunar orbit. It orbited the Moon four times, getting gradually closer to the lunar surface with each orbit.
Finally, Chandrayaan-3 was put in a circular orbit around 100 kilometres above the lunar surface and the lander with the rover was separated from the Propulsion Module.
Chandrayaan 3 lander
The Chandrayaan-3 lander which has its own thruster system, navigational and guidance controls, and hazard detection and avoidance systems started its descent once the space craft was on top of the Lunar South Pole.
The Chandrayaan Lander then slowly descended to the surface with highly controlled speed with use of thruster and proper navigation to touch down at the scheduled landing place on the south polar region of the Moon. The speed was very low almost less than 8 kilometers per hour.
The safe touchdown was the most crucial phase because higher speeds could have resulted in a crash on the Moon. The propulsion module of Chandrayaan-3 will stay in orbit around the moon, remaining in communication with the rover and the lander.
Actually the success this time can be attributed to the significant changes being made after the 2019 Chandrayaan crash like strengthening of the lander’s legs, equipping the craft to withstand any increase in the speed of landing as well as new sensors to measure the craft’s speed of approaching the Moon.
This success will definitely inspire India to feel more confident and venture out into the exciting arena of outer Space and whole wide Universe.
| Edited by Sameer Khan | 
