At 2:35 pm IST on July 14, 2023, Chandrayaan-3 lifted off from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh leaving behind a plume of smoke and fire. About 16 minutes later, ISRO’s mission control announced that the rocket had successfully managed to put the Chandrayaan-3 lander into an Earth orbit that will send it looping toward a moon landing next month.
The word “Chandrayaan” is derived from the Sanskrit words “Chandra” (meaning “Moon”) and “Yaan” (meaning “vehicle” or “craft”). Chandrayaan is the name of the Indian Space Research Organization’s series of robotic missions to the Moon.
Significantly, ISRO decided to launch Chandrayaan-3 in the month of July, when the moon is closest to the Earth. During that period the moon is 3,61,934 kilometres away from Earth — that means more than 21,000 kilometres closer to the earth. This leads to saving both time and fuel required to push a lander and rover onto the surface of the moon. This distance between the earth and the moon keeps changing because the moon orbits the Earth in an elliptical orbit rather than a circular one.
Another significance of July is that the moon is brighter in the night sky than any other full moon. This special phenomenon is termed the supermoon or Buck Moon.
Chandrayaan-3 is India’s third lunar exploration mission to the Moon. One of its main objectives is to collect more information about the mineral composition on the surface of the Moon.
Over the next 40-42 days, Chandrayaan-3 is expected to cover a distance of 384,400 kilometres (about 30 times the diameter of Earth) and land on the South Pole region of the Moon on August 23 or 24, 2023. The Moon’s distance from Earth is constantly changing due to the gravitational pull of the Sun and other planets.
If it goes as scheduled, India would be the fourth nation — after the United States, Russia and China — to soft-land (a controlled lunar landing) a probe on the moon. This will also make India the first country to make its locally produced vehicle land on the lunar South Pole.
The lunar South Pole is a place no humans have ever gone before. It is a completely unexplored world. The South Pole is also a good target for a future human landing.
To date, all the space missions by US, Russia and China, which managed to put their robotic equipment on the Moon’s surface, landed close to the Moon’s equator (the side facing the Earth), which requires less fuel. All these landings took place soon after local sunrise when the sun kept charging the solar panels but the lunar surface was cool and navigation was easier.
In contrast, landing on the South Pole has been considered problematic because of the topography of the region where there is no sunlight for millions of years.
However, the lunar South Pole is important to humankind because of the expected presence of water in the form of ice there. Since India’s first mission to the Moon, ISRO has wanted to find out more about the possibility of water on the Moon. This apparently was the reason why it decided to put its lander and rover unit close to the south pole of the Moon.
“It is indeed a moment of glory for India and a moment of destiny for all of us here at Sriharikota, who were part of history in the making,” Minister of State for Space and atomic energy Jitendra Singh, said while addressing ISRO scientists on the mission’s launch.
Chandrayaan-3 Rover is a major step forward for India’s space program and is a testament to the country’s growing technological capabilities, and understanding of the Moon.
Chandrayaan-3 mission’s main objectives include:
- To demonstrate a safe and soft landing on the surface of the Moon.
- To demonstrate the rover’s loitering capabilities on the Moon
- To conduct in-situ scientific experiments on the chemical and natural elements, soil, water, etc. to understand the composition of the Moon.
Chandrayaan-3 mission’s components include an indigenous Lander module (LM), a Propulsion module (PM) and a Rover with the objective of developing and demonstrating new technologies required for Interplanetary missions. The Lander has the capability to soft land and deploys the Rover to carry out in-situ experiments on the lunar surface over the course of a single lunar day of operation (equivalent to about 14 Earth days). The main function of the PM is to carry the LM from launch vehicle injection to the final lunar 100 km circular polar orbit and separate the LM from the PM. The Propulsion Module also has one scientific payload, which will be operated post-separation of the Lander Module. The GSLV-Mk3 launcher will place Chandrayaan-3 in an Elliptic Parking Orbit (EPO) of size ~170 x 36500 km.
ISRO has taken special measures to improve its onboard equipment for a safe and sure soft landing on the lunar surface and eliminate the weaknesses of the previous missions. The Chandrayaan-3 lander has its own navigational controls, hazard detection and avoidance systems.
Apart from Earth, the Moon is the only celestial body humans have visited. More than 140 missions launched to the moon. A small number of them had astronauts on board, but most of the missions were robotic orbiters, landers and rovers.
According to ISRO, Chandrayaan-3 can’t just head straight from an Earth orbit to landing on the moon. Hence, Chandrayaan-3’s approximately 40-day journey to the moon will comprise three phases namely: the Earth-centric phase, the lunar transfer phase and the moon-centric phase.
Phase 1 is now partially over, with the prelaunch and launch and ascent periods completed by liftoff and the separation of Chandrayaan-3 from its rocket. The mission is now in the Earth-bound manoeuvre stage, which is part of Phase 1.
Phase 2- During this segment Chandrayaan-3 will make five orbits around Earth. Each swing will take the spacecraft away from planet Earth. Accordingly, the final sweep will place Chandrayaan-3 on a lunar transfer trajectory, sending it moonward.
Phase 3- Chandrayaan-3 will make an entry into the lunar orbit. Chandrayaan-3 will then orbit the moon four times, getting gradually closer to the lunar surface with each subsequent loop.
If all goes as planned, the Chandrayaan-3 lander will touch down in the south-polar region of the moon, at a speed of under 5 mph (8 kph) while the propulsion module will stay in orbit around the moon, communicating with the rover and the lander. The lunar landing is scheduled to take place on August 23 or 24, when the sun rises on the moon. This should allow Chandrayaan-3 fourteen (14) days to work. However if due to any reason, the landing cannot happen on these two dates, ISRO will have to wait for another month and land in September.
After the safe landing is achieved, the Chandrayaan-3 rover equipped with LASER Induced Breakdown Spectroscope (LIBS), and Alpha Particle X-ray Spectrometer (APXS) will venture out to investigate the chemical composition of the lunar rocks and soil around the Chandrayaan-3 landing site.
As the rover goes about its business, the lander that carried it down to the surface will measure plasma — a gas of electrons and ions — at the lunar surface and how it changes over time with the help of Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere (RAMBHA) instrument. The lander will also try to measure the thermal properties of the South Pole region and measure the moon’s seismicity to help analyse the structure of the lunar crust and mantle.
It is worth mentioning that the moon is a ready-made laboratory and the world’s largest vacuum chamber to undertake experiments for understanding the universe in general and the evolution of Earth in particular. Recently several robotic Moon missions have been launched to understand more and more about the surface of the Moon.
The Moon is the only natural satellite of Earth. It is believed to have been formed about 4.5 billion years ago when a large amount of debris from an explosion on Earth fused together to form the Moon in space.
The Moon is a mysterious place with mountains, valleys, craters, and lava flows. There is also evidence to believe that there is a possibility for humans to survive because of the presence of water on the Moon’s surface.
Even today, Chandrayaan-1 is remembered for being the first mission to discover moon ice.
Chandrayaan-1, India’s first mission under the Chandrayaan program, was launched on October 22, 2008. It was India’s first mission to the Moon and marked a significant milestone in the country’s space exploration efforts. Chandrayaan-1 carried several scientific instruments, including a lunar orbiter and an impactor probe called the Moon Impact Probe (MIP). The mission successfully completed its objectives, including mapping the lunar surface and confirming the presence of water molecules on the Moon.
The second mission, Chandrayaan-2, was launched on July 22, 2019. It was a more ambitious mission that aimed to land a rover on the lunar surface. Chandrayaan-2 consisted of an orbiter, a lander called Vikram, and a rover named Pragyan. The lander and rover were intended to perform scientific experiments on the Moon’s surface. However, during the landing attempt on September 7, 2019, contact with the lander was lost, and the mission did not achieve a soft landing. Despite the partial failure, the Chandrayaan-2 mission was still considered a significant achievement for India’s space program.
-The writer is a seasoned media professional with over three decades of experience in print, electronic, and web media. He is presently Editor of Taazakhabar News