ISRO has shown that setbacks can fuel determination and lead to remarkable accomplishments.
August 23, 1966: A NASA spacecraft captured the first-ever photograph of Earth from the moon.
August 23, 2023, 06:00 PM, I.S.T.
“India is on the moon,” announced the chief of Indian Space Research Organization (ISRO) S. Somanath, highlighting the achievement with joy and pride.
Two Indian visitors, a lander named Vikram, and a rover named Pragyan made history as they successfully landed on the moon’s south pole, a region that has never been explored before.
The two Indian robotic explorers, part of the Chandrayaan-3 mission, aim to study the lunar surface and its resources. The success of Chandrayaan-3 is even more remarkable, as it has reached a part of the moon that no one has ever seen.
Chandrayaan-3 was launched on July 14, 2023, from the Satish Dhawan Space Centre in Sriharikota at 2:35 pm.
The success of the Chandrayaan-3 mission was the result of ISRO’s setback from their previous lunar landing attempt in 2019.
The failure of Chandrayaan 2
India’s second lunar mission, Chandrayaan-2 launched on July 22, 2019, also Vikram and Pragyan.
The lander and rover were supposed to touch down on the lunar surface on September 7, 2019, but Vikram lost contact with the ground station when it was only 335 metres (0.335 km) away from the Moon.
The poignant image of former ISRO chief K Sivan’s tearful moment after Vikram’s communication was lost remains etched in our memories. Sivan could not hold back his tears even after receiving words of encouragement from the PM himself.
Learning from failures: Key to success
Fast forward to June 10, 2023, when ISRO’s data analysis revealed that Vikram failed to slow down enough during the final phase of its descent, which started from an altitude of 5 km and ended at 400 m. As a result, Vikram crashed on the Moon at a high speed instead of making a gentle vertical landing (soft landing).
ISRO Chairman S Somanath spoke to the media and shed light on the main reasons for Vikram’s hard landing.
First, the five engines that were used to reduce the velocity of the lander produced more thrust than expected, which led to errors in the trajectory.
Second, the errors accumulated to a level that exceeded the software’s ability to correct them, and the lander started to spin very fast.
Third, the lander increased its velocity again as it approached the surface, because the landing site was too far from its position. Also, the landing site was a small area of 500 m x 500 square meter area.
In short, a last-minute software glitch led to the failure of the Chandrayaan 2 mission.
ISRO: Totally over the moon
Chandrayaan-3 is a story of innovation and redemption. It was different from Chandrayaan-2 in several ways. It has a “failure-based design” that anticipates and prevents possible errors during the landing, unlike the “success-based design” that assumed everything would go as planned.
Some of the course corrections made by the scientists and engineers from ISRO in Chandrayaan-3 were:
Making the landing area larger (4 km x 2.5 km) to give more flexibility and safety to the craft.
The craft has more fuel to adjust its position and find an alternative landing site if needed.
The craft only needs to take one image, compare it with stored data, and land. It does not have to calculate the landing spot immediately, which was a problem for Chandrayaan-2.
The craft has extra solar panels to generate power after landing, no matter how it lands.
The craft has a higher vertical velocity component, from 2 meters per second to 3 meters per second, to reduce the impact of horizontal velocity.
Chandrayaan-3 also underwent rigorous testing to ensure its reliability. It was tested for vibration, flying, and landing scenarios using various methods.
ISRO claimed that Chandrayaan-3 can handle six times sigma or general failure scenarios.
The moon is beautiful, isn’t it
While the Chandrayaan-2 mission was a bold attempt by ISRO to explore the Moon, it ended in disappointment when the lander Vikram crashed on the lunar surface.
However, ISRO did not give up on its lunar ambitions and launched Chandrayaan-3, a revised and improved version of Chandrayaan-2, with a failure-based design and extensive testing.
The mission also marked a milestone for ISRO, as it has demonstrated its resilience and innovation in the face of adversity. Chandrayaan-3 is not only a scientific achievement, but also a source of inspiration and pride for India and the world.
As I complete this piece, I suddenly realize that Vikram and Pragyan are already set to work.
“Humanity was born on Earth. Are we going to stay here? I suspect—I hope—the answer is no.” —Ann Leckie, American author of science fiction and fantasy.
