The Success of Chandrayaan 3

The poignant image of a Prime Minister consoling a scientist remains etched in the memory of people who watched the launch of Chandrayaan 2 in 2019. The lander of Chandrayaan 2 was unable to make a soft landing. It was a huge disappointment for all.  However, ISRO declared that the mission was a partial success. Is failure not a part of success? Yes, it definitely is.

Ready for launch Chandrayaan3 Source: ISRO

India began its first deep space mission with Chandrayaan 1 in 2008. It discovered the presence of water on the lunar surface. The water molecules were found trapped or locked between the mineral grains. An exciting discovery, as water is the most important resource needed for human survival anywhere in this cosmos.

Along with a gamut of scientific instruments, it also carried an impact probe to study the moon's exosphere. The 35-kg probe's video imaging system collected data and captured images of the lunar surface for future landing missions, especially potential landing sites.

Pre-launch testing of Chandrayaan1  Source: Wikimedia Commons

Chandra’s Altitudinal Composition Explorer (CHACE Mass Spectrometer)  aboard the probe analysed the lunar exosphere. The findings of CHACE were quite significant.  It showed the presence of water along with a dominating presence of carbon dioxide in the exosphere.   It recorded the presence of elements with heavy mass. and gases like helium, argon, and neon. The probe crashed near the Shackleton Crater at the sunlit side of the South Pole of the moon. All these discoveries made this mission a huge success.

SouthPole of the moon Source: Wikimedia Commons

Encouraged by this historic mission, ISRO planned for Chandrayaan 2. This time, the main objective was to soft-land a lander with a rover. Apart from investigating the origin, composition, and distribution of water on and below the surface, the rover's mission was to study cold traps in the lunar craters.

Integration of Payloads on Chandrayaan 2 Source: Wikimedia Commons

The Earth's axis is tilted at an angle of 23.5 degrees but the lunar axis is tilted at 1.5. Due to this very small angle, sunlight never reaches the bottom of certain craters on the moon. These regions are permanently cold and dark.  Scientists believe that these permanently shadowed craters might hold huge reservoirs of water in the form of ice.  Not only that, these mysterious craters could help us understand the origin and evolution of the moon as they have remained unchanged for over two billion years. The moon is like a fossil record and can help us decode the secret stories of the early solar system.

A cold trap of Shackleton Crater on the moon Source: Wikimedia Commons

Chandrayaan 2's rover was designed to meet these ambitious objectives.  After a successful launch and separation from the orbiter, the lander was descending to the lunar surface.  About 2.1 km from the lunar surface, the lander faced several glitches during the rough breaking phase.    The lander could not slow down as required and the rapid descent led to huge vibrations creating problems in the software as well as the power supply.

ISRO lost contact with the lander. It was a very distressing time for the scientists, as they were unable to communicate with the lander.  The lander crash-landed on the harsh lunar landscape.  The rover remained immobile.  Due to this major setback, many of the objectives of Mission Chandrayaan 2 couldn't be met.  But it set the ground for the next follow-up mission Chandrayaan 3.  ISRO came up with a failure-based design wherein every possible scenario for failure was anticipated and measures were taken to counter each of it.

The lander was redesigned to make it heavy and sturdy to bear the impact of landing.  The improved software looked into all the important parameters with possible variations to help in the descent.  A large area of 4.5 km by 2.5 km was identified for the landing site. The spacecraft was empowered with two powerful engines, larger fuel tanks, and enough solar panels to ensure adequate power supply. Chandrayaan  2 provided the insight required for the success of Chandrayaan 3.  With this level of preparedness, ISRO launched Chandrayaan 3 successfully.   It landed on the South Pole after a travel time of 41 days.  ISRO named the point of landing as the SHIVSHAKTI Point.

Vikram Lander on the Moon Source: ISRO

India became the fourth country on this planet to achieve a soft landing on the moon and the first to land on the south pole. India entered into the exclusive league of nations that are at the forefront of deep space missions. This achievement was not just India's but dedicated to all humanity.