It was meticulous data analysis for about eight hours everyday and burning the midnight oil that helped him zero in on the crash site, says Chennai based software engineer Shanmuga Subramanian credited for helping US space agency NASA to discover Chandrayaan-2's Vikram lander's debris on the lunar surface.
For the 33-year-old graduate in mechanical engineering, it was sheer hardwork that involved poring over many gigabytes of images released by NASA over three weeks sans any high end technology or other gadgets that led him to his "eureka moment."
Hailing from the temple town of Madurai, he says he used two laptops to identify the site where Vikram crashed and to compare the satellite images captured before and after.
At one stage, he thought if a particular spot on the lunar surface was not that of the lander crash, nothing else could be and such a level of confidence stemmed after a thorough analysis.
Every day after returning from work at a top IT firm, he used to analyse data between 10 pm and 2 am and again from 8 am to 10 am before going to office.
Before sending an email to NASA, he was sure that he had done a clean analysis, he said.
On what prompted him to take up the analysis, he told news agency PTI that he had keenly watched the satellite launches of ISRO after completing school education.
"Watching those launches kindled some kind of interest in me to explore more," he said.
"Apart from my office hours (at Lennox India Technology Centre), I was following what NASA and California-based SPACEX were doing," Mr Subramanian said.
This interest eventually spurred him to work on lunar satellite data. He said mechanical engineering had links to rocket science as well and that too played a part in his understanding of rocket science.
Mr Subramanian, fondly called "Shan" by his family and friends, said he did expect a reply from NASA as soon as he positively identified the crash site and sent the email.
"I thought they will reply after doing their own verification and around 3 am on Tuesday I received an email from them," he said.
He said none of his family members were into space technology.
"I got a message from former ISRO top scientist Mayilsami Annadurai appreciating me," he said, adding the office too lauded his achievement.
Asked if he would shift to a field related to space technology, Mr Subramanian, an application developer by profession, said he would continue to pursue his passion only "outside of my work."
"I need to study more."
Hailing from a humble background, Mr Subramanian's father is a retired provident fund inspector and mother a school teacher. He has a sister who is also a software engineer at Chennai.
NASA has marked the location of the crash site ''S'' giving credit to Subramanian for his discovery.
"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 in the email sent to Mr Subramanian.