The modest two-bedroom apartment of Shanmuga Subramanian, a 33-year-old techie in Chennai, was choc-a-bloc on Tuesday morning, packed with journalists eager to speak to him about his ‘clue’ that led to the discovery of the Vikram Lander’s debris on the moon.
On curious questions about how he stumbled upon the debris, which has provided a sort of on the date of the Lander, he casually says that what he did was not rocket science. According to Mr. Subramanian, all it took was two computers and roughly 30 hours of effort to spot what looked like the debris of the Lander. NASA confirmed it this Tuesday morning, crediting Shan, as he likes to be called, for the clue.
Shan, a native of Madurai and a Mechanical Engineering graduate from Government College of Engineering in Tirunelveli, has always been curious about space science. He was one of the thousands of Indians, who were awake throughout the night and following minute-by-zminute updates of the Chandrayaan 2 mission’s landing on the lunar surface on September 7. He was heartbroken when the Lander went incommunicado during the landing.
Though he was reading up and following updates on the mission from space scientists and enthusiasts across the globe, his curiosity peaked when NASA released images from its Lunar Renaissance Orbiter (LRO) that flew over the area of Vikram Lander’s landing. “LRO flew over the area on September 17 and NASA released the images through a blog on September 29,” he said.
Over the next three to four days, Shan spent 7 to 8 hours a day comparing this image with images taken by LRO of the same area before Vikram Lander had crashed. The images were of roughly 1.5 GB size and had a resolution of 1.25 square metre per pixel. There were vertical and horizontal lines with each square marking an area of one square kilometre..
“While I was initially not sure where to look, later I found the intended landing site of Vikram Lander and started looking in the adjacent squares for differences,” he said. He learnt from the information he read from multiple sources that the crash landing must have happened to the north of the intended landing site. This led him to further narrow down the area of research.
He says he did not use any advanced software tools apart from basic image viewing tools. “I thought about developing an image processing tool for this purpose. But then decided that it was too much effort,” Shan, who says he has developed multiple tools for weather monitoring and clutter-free viewing of websites on mobile phones, said.
“The method I used was very crude. Just have the images open side by side and go through pixel after pixel,” he added.
Shan did have few false positives. “Some of the differences I spotted turned out to be boulders. Then I learnt that reflections from natural objects on the lunar surface will be brighter. I used that information to discard other false positives,” he said.
On October 3, he tweeted tagging NASA and ISRO about a spot, which he believed could have part of the debris. On October 18, he emailed NASA. “But I couldn’t email ISRO since I did not have the right contact.” In the early hours of Tuesday, NASA confirmed his finding and emailed him.
Shan said his colleagues did not take him seriously when he told them that he was trying to find the Lander. “Now, I can go to office and tease them back,” he quipped.
He added that Chandrayaan 2 orbiter’s image are of far higher resolution than that of LRO. “If ISRO also makes images public like that of NASA, it will help more aficionados like me to be involved in, and possibly contribute to the research in some small way,” he said.
