CHENNAI: Believe it or not, this Chennai techie with rudimentary knowledge about space exploration has solved the mystery behind the missing Chandrayaan-2 Vikram lander, leaving ISRO and NASA scientists dumbstruck. Meet Shanmuga Subramanian (33), an IT architect and rookie space enthusiast, who became a sensation by helping NASA locate the Vikram lander.
It had gone incommunicado minutes before attempting a soft-landing on the moon on September 7. Since then, both ISRO and NASA were frantically searching for it, deploying the most sophisticated satellites and image processing techniques. In a chat with Express at his house in Adyar, Subramanian opens his laptop which contains downloaded images of moon’s surface captured by NASA’s Lunar Reconnaissance Orbiter Camera (LROC) and explains how he made the discovery.
“First, what we knew is the ISRO’s intended landing site of Vikram lander. So, I decided to look for possible crash landing signs within 4 sq.km. NASA’s LROC first flyby over the landing site was on September 17 and the US space agency released a mosaic image of the site on September 26.
I downloaded it along with previous LROC images upto last nine years. Then, I began comparing manually, pixel by pixel, to locate any noticeable difference. I spent seven to eight hours every day for four days, and finally on October 3, I found a tiny little white speck that was not found in earlier images. For me, that was the piece of Vikram lander. You may call it a hunch, but NASA on Tuesday credited me for the discovery,” he says.
On why ISRO and NASA were unable to see what he found with his naked eyes, Subramanian says, “Being an amateur, I was excited with every new element found. There were several false positives. But, I finally found what I was looking for.” However, a few ISRO scientists are questioning the claim.
Compared images for 7-8 hours a day
Shanmuga Subramanian downloaded NASA’s Lunar Reconnaissance Orbiter Camera images upto last 9 years. Comparing the images for 7 to 8 hours a day, he finally found a white speck on October 3, that was not found in earlier images.
‘Had no data about path of Vikram lander’
Subramanian says though there was no data available about the path of Vikram lander, “I eventually concluded it would have come from North Pole as one of the tweets said about Vikram crossing North Pole of the Moon. From ISRO’s live images, I made out that it would have stopped short of around 1 km from the landing spot. So, it eventually made me search around 2 sq km around the landing area.”
Subramanian had written to NASA about his findings on October 28. On Tuesday, NASA officially credited him for the discovery.
“The debris first located by Shanmuga is about 750 metres northwest of the main crash site and was a single bright pixel identification in that first mosaic,” NASA said, adding that after receiving the tip, the LROC team confirmed the identification by comparing the before-and-after images.
The November mosaic had the best pixel scale (0.7 metre) and lighting conditions. “It showed 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,” said NASA.