The United States space agency National Aeronautics and Space Administration on Tuesday credited Indian engineer Shanmuga Subramanian for first finding the debris from the Chandrayaan-2 mission’s lander.

“Shanmuga Subramanian contacted the LRO [Lunar Reconnaissance Orbiter] project with a positive identification of debris,” the space agency said. “After receiving this tip, the LROC [LRO Camera] team confirmed the identification by comparing before and after images.”

The 33-year-old mechanical engineer from Chennai told NDTV that he alerted the findings to both NASA and the Indian Space Research Organisation. Subramanian said he received a good response from the scientists at NASA.

“I did send a tweet to NASA and ISRO,” he said. “I sent emails to a couple of NASA scientists. “They were in charge of the LRO images. I got a good response from them.”

Chandrayaan-2’s Vikram lander had attempted a soft landing on the moon on September 7, but lost communication with the ISRO minutes before touchdown. Its debris was strewn across about 750 metres of the crash site.

Subramanian said he worked for up to seven hours everyday in his Chennai residence to locate the lander. “I narrowed my search to 2 sq km. I used only a laptop and searched all the images,” he said.

NASA had released the first mosaic image of the site, acquired on September 17, on September 26. It had invited the public to compare it with images of the same area before the crash to locate the lander.

The engineer said NASA’s inability to find the lander on its own had sparked his interest. He added that he was the first person to come up with a positive identification. “It’s quite big but it is a little sad at the same time because we all expected Vikram to land on the surface,” Subramanian told the television channel. “I hope ISRO will again have a successful Chandrayaan-3 and they will be able to land on the moon next time.”

In an image released by NASA, the space agency pointed out: “Green dots indicate spacecraft debris [confirmed or likely]. Blue dots locate disturbed soil, likely where small bits of the spacecraft churned up the regolith. ‘S’ indicates debris identified by Shanmuga Subramanian.”

Subramanian told AFP that he did a side-by-side comparison of the before and after impact of Vikram lander using two of his laptops. He said he was helped by fellow Twitter and Reddit users. “NASA has to be 100% sure before they can go public, and that’s the reason they waited to confirm it, and even I would have done the same,” he added.