Chennai techie helps NASA find Chandrayaan-2's Vikram lander debris on lunar surface

Chandrayaan-2's Vikram lander, which crashed on the surface of the Moon in September, has been found by NASA, the US space agency confirmed on Tuesday, lauding a Chennai-based techie who helped it trace the debris of India's ambitious lunar mission by spending hours comparing before and after images of the landing site.

NASA's confirmation came nearly three months after India's Chandrayaan-2 mission made a hard landing near the uncharted lunar south pole in the wee hours of September 7. "The Chandrayaan2 Vikram lander has been found by our NASA Moon mission, the Lunar Reconnaissance Orbiter. See the first mosaic of the impact site," NASA said in a tweet sharing before and after impact images.

Blasting off in July, India had hoped with its Chandrayaan-2 mission to become just the fourth country after the United States, Russia and regional rival China to make a successful moon landing, and the first on the lunar south pole. The main spacecraft, which remains in orbit around the moon, dropped the unmanned lander Vikram for a descent that would take five days, but the probe went silent just 2.1 kilometers above the surface. Vikram, with rover 'Pragyan' housed inside it, hit the lunar surface after communication with the ground-stations was lost during its final descent.

Vikram attempted landing on a small patch of lunar highland smooth plains between Simpelius N and Manzinus C craters. 

On September 26, NASA released a mosaic image of the lunar site where India's Vikram lander crashed. NASA released an image taken by its Lunar Reconnaissance Orbiter (LRO) that showed the site of the spacecraft's impact (September 6) and associated debris field, with parts scattered over almost two dozen locations spanning several kilometers.  The organisation invited the public to search it for signs of the lander. 

The first person to come up with a positive identification was Chennai-based IT professional Shanmuga Subramanian, reportedly employed at Lennox India Technology Centre in Chennai, who confirmed the identification of the crashing site of Vikram by comparing before and after images.

On October 3, Subramanian, a Chennai-based mechanical engineer, had tagged the twitter handles of NASA, LRO and ISRO in a tweet, asking, "Is this Vikram lander? (1 km from the landing spot) lander might have been buried in Lunar sand?".

On November 17, he further zeroed in on his observations and tweeted out the possible crash site of the lander.

"This might be Vikram lander's crash site (Lat:-70.8552 Lon:21.71233 ) & the ejecta that was thrown out of it might have landed over here (The one on the left side was taken on July 16th & one on the right side was from Sept 17)," he said in a tweet accompanying the images.

The LROC team scoured the surrounding area in these new mosaics and found the impact point about 2,500 feet to the southeast of the planned touchdown site, and a spray of debris emanating outward. The November mosaic had the best pixel scale (0.7 metre) and lighting conditions (72 degrees incidence angle), NASA said. 

"The November mosaic shows best the impact crater, ray and extensive debris field. The three largest pieces of debris are each about 2x2 pixels and cast a one pixel shadow," the statement said.

"NASA has credited me for finding Vikram lander on Moon's surface Vikram lander Chandrayaan-2," Subramanian said in another tweet on Tuesday.

"Thank you for your email informing us of your discovery of debris from the Vikram lander. The LROC team confirmed that the location does exhibit changes in images taken before and after the date of the landing," said deputy project scientist Lunar Reconnaissance Orbiter mission John Keller.

"Using this information, the LROC team did additional searches in the area and located the site of the primary impact as well as other debris around the impact location and has announced the sighting on the NASA and ASU pages where you have been given credit for your observation," Keller said.

"I apologise for the delay in getting back to you. We needed to be certain of our interpretation of the observation as well as making sure that all stakeholders had an opportunity to comment before we could before we could announce the results. Congratulations for what i am sure was a lot of time and effort on your part," the scientist in his letter to Subramanian who shared it on Twitter.

-Inputs from PTI