India’s third lunar mission, Chandrayaan-3, has successfully performed its final maneuver before it can land on the Moon. On Saturday, the mission’s lander module successfully executed a second deboosting, in which its orbit was modified.
The lander module, comprising the lander Vikram and the rover Pragyan, will be prepared to touch down on the lunar south pole on Wednesday at 18:04 India time (IST), the country’s space agency confirmed. This brings India closer to become the fourth country, after the USSR, the US and China, to successfully land a vehicle on the Moon.
“The second and final deboosting operation has successfully reduced the LM orbit to 25 km x 134 km. The module would undergo internal checks and await the sun-rise at the designated landing site,” the India Space Research Organisation (ISRO) said in a tweet.
“There will always be a small non-zero probability that it can go wrong and we cannot eliminate that,” Annapurni Subramanian, senior astronomer and director of the Indian Institute of Astrophysics (IIA) told News18, adding, “I’m quite certain that we will make it this time. A huge amount of preparation has gone into it and Chandrayaan-3 has the highest probability of being successful.” A similar effort by ISRO in 2019 ended in failure.
ISRO’s announcement came hours before the Russian space agency on Sunday confirmed that Moscow’s own Moon mission Luna 25 was lost after an incident during pre-landing maneuvers. “The Luna-25 spacecraft switched to a non-designated orbit and ceased to operate due to a collision with the surface of the Moon,” Roscosmos said in a statement. Chandrayaan-3 is expected to land on the south polar region of the moon, which was also the targeted destination for the Luna 25 mission. No other country has made a soft landing on the lunar south pole, which is believed to have ice deposits that could hold significant value for future explorations.
News agency PTI earlier quoted ISRO Chairperson S Somanath as saying that India’s spacecraft positioning will be critical to landing the Chandrayaan-3 mission on the Moon. “The ability to transfer the spacecraft from horizontal to vertical direction is the ‘trick we have to play’ here,” Somanath explained. The velocity at the start of the landing process is almost 1.68 km per second [over 6,000km per hour], but this speed is horizontal to the surface of the moon. The Chandrayaan-3 here is tilted almost 90 degrees, it has to become vertical, the report noted.
Scientists behind India’s third mission have been pointing out that Chandrayaan-3 has learned from the failures of the second mission, Chandrayaan-2, in July 2019 but failed to soft-land on the Moon, crashing on touchdown.
According to Somanath, the second mission’s spacecraft had used five engines to reduce its velocity and these developed a higher-than-expected thrust. “All the errors got accumulated, which was on the higher side than what we had expected. The craft had to make very fast turns. When it started to turn very fast, its ability to turn was limited by the software because we never expected such high rates to come. This was the second issue,” the ISRO chief told PTI last month. The third reason for failure was the small, 500m x 500m, site identified for landing the spacecraft. “The craft was trying to reach there by increasing the velocity. It was almost close to the ground and kept on increasing the velocity,” Somanath explained.
India’s 2023 Moon mission set off from Earth on July 14. While on its way to the Moon, the probe has been taking many photos. On August 18, ISRO shared the image of Chandrayaan-3’s free-flying propulsion module. Before that, images of the Moon were captured by the Lander Position Detection Camera (LPDC). Meanwhile, India has announced it’s to launch the first space-based Indian observatory to study the Sun, called Aditya-L1, next month.