He was born into a poor family. His father, Kailasavadivoonadar was a paddy and mango farmer. Sivan had helped his father in farmlands and used to sell mangoes in the market.
Due to poor financial conditions of his family, his brother and sisters could not receive higher education.

An old photo of Sivan and his mother
His first school was a small Tamil medium school, which was situated very near his home.

The School in which Sivan studied
He was a very calm and studious child. According to his uncle, A Shunmugavel, Sivan was very studious and hard-working. He had never received any tuition. He had scored 100% marks in Mathematics in BSc.
He is the first graduate of his family and his village as well.

An old photo of Sivan (Extreme Left) and his friends
Having known the talent of Sivan, his father sold some part of his land and borrowed some money from others to get Sivan enrolled at the Madras Institute of Technology (MIT).
According to Sivan, he used to go to school barefoot. Before getting enrolled at the Madras Institute of Technology (MIT), he used to wear ‘dhoti/lungi.’ In MIT, he wore pants for the first time.

An old photo of the Classmates and Teachers of Sivan
After joining the ISRO in 1982, Sivan participated in the PSLV (Polar Satellite Launch Vehicle) Mission. He was entrusted with contributing to end-to-end planning, design, integration, and analysis.
He was given a nickname, ‘Rocket Man’ for developing cryogenic engines for India’s space programs. He also enabled rockets to be launched under different weather and wind conditions.

Sivan and R Umamaheswaran with the model of a rocket
He is known as a specialist of 6D trajectory simulation software, which helps predefine the path of the trajectory.
In 2011, Sivan joined GSLV (Geosynchronous Satellite Launch Vehicle) project. He has also contributed to the Reusable launch vehicle project.
In February 2015, he played an important role in launching 104 satellites in one time by PSLV-C37.
Since 1982, Sivan has been the part of almost all rocket programs.
On 15 January 2018, he assumed the charge of the chairperson of the ISRO; having replaced A. S. Kiran Kumar.

Sivan with A. S. Kiran Kumar
Under his chairmanship, the ISRO launched its second lunar exploration mission, “Chandrayaan 2” on 22 July 2019.
After the launch of Chandrayaan 2, he along with whole ISRO team was congratulated by the Indian Prime Minister, Narendra Modi
, Presidents of other Space Agencies of the world, and many other renowned personalities.

Sivan while meeting with Mr. Jean Yves Le Gall, the President of French National Space Agency
Before landing on the moon’s surface, Lander Vikram had lost its communication. Thereafter, the Prime Minister, Narendra Modi
motivated and addressed the scientists of the ISRO. While meeting with the Prime Minister, Sivan got emotional and broke down in tears. Narendra Modi hugged and consoled him.