Indian Space and Research Organisation (ISRO) scientist N Valarmathi, known for her iconic voice during rocket countdown launches, died on Saturday. Her most recent countdown happened during the launch of Chandrayaan-3, India's ambitious moon mission that scripted history.

A former ISRO Director Dr. P V Venkitakrishnan took to X, formerly Twitter, to condole her demise and wrote, ''The voice of Valarmathi Madam will not be there for the countdowns of future missions of ISRO from Sriharikotta. Chandrayan 3 was her final countdown announcement. An unexpected demise . Feel so sad. Pranams!''

According to reports, she suffered a heart attack and died in Chennai on Saturday evening. 

Ms Valarmathi, a native of Tamil Nadu's Ariyalur, was born on July 31, 1959. She went to the Nirmala Girls Higher Secondary School before graduating in engineering from the Government College of Technology in Coimbatore.

The scientist joined ISRO in 1984 and played a pivotal role in numerous missions. She was the project director of RISAT-1, India's first indigenously developed Radar Imaging Satellite (RIS) and the country's second such satellite.

In 2015, she became the first person to receive the Abdul Kalam Award, instituted by the Government of Tamil Nadu in honour of the former president Abdul Kalam in 2015.

Condolences are pouring in on social media to pay tribute to the late ISRO scientist. 

One user wrote, ''I am so sorry to hear about the passing of Valarmathi Madam. She was a true inspiration to many, and her voice will be missed during every launch. Om Shanti.''

Another commented, ''I noticed her absence during the #AdityaL1 launch. I thought she might be out of the office or something. But I didn't expect this sad news. I'll really miss her. Om Shanti.''

A third said, ''Very, very sad to hear this. We worked closely with her for our Vikram-S launch last year, for which she was the voice for the launch countdown.''

A fourth added, ''Her voice embarked the begining of the remarkable historic journey for the country. She will be remembered always in the iconic moment of Indian space acomplishments. May her soul rest in peace and God give strength to her family.''