A tribute to Ramakrishnan of ISRO

It was a phone call from S. Somanath, Director, Vikram Sarabhai Space Centre (VSSC), ISRO, Thumba, Thiruvananthapuram, on the morning of December 1, 2020. He came to the topic at once. "I have some sad news for you," he said. "Ramakrishnan sir passed away. He died in his sleep. You used to quote him often in your stories on ISRO launches." A grief-stricken Dr Somanath added, "Ramakrishnan was my guru. I owe a lot to him." I was touched by what the VSSC Director said. 

A few hours later, I received a WhatsApp message from M. Annadurai, former Director, U.R. Rao Satellite Centre, ISRO, Bengaluru. It said, "Hope you know the sad news that Mr S. Ramakrishnan, former Director, VSSC, is no more." Ramakrishnan was 71 years old when he died on December 1, 2020.  He capped his remarkable career by retiring as the  Director of VSSC, the nerve-centre of ISRO, which designs and builds its rockets. He was earlier Director, Liquid Propulsion Systems Centre (LPSC), situated at Valiamala, about 40 km from Thiruvananthapuram. The entire VSSC community, which fondly called him “Ramakrishnan sir”, was saddened by his death.

S. Ramakrishnan was a genius in rocketry. But he carried his expertise in the field lightly on his shoulders. He made his mark as the Mission Director of ISRO's Continuation flights of the Polar Satellite Launch Vehicles (PSLVs) called PSLV-C1, C2, C3 and C4. He stabilised the PSLV programme and made it the most trusted workhorse of ISRO. After the first PSLV flight failed to put the Indian Remote-sensing Satellite (IRS-1E) into orbit due to a software glitch on September 20, 1993, G. Madhavan Nair became the Mission Director of the next two PSLV flights in 1994 and 1996. Those two flights were remarkably successful in putting IRS-P2 and IRS-P3 satellites into orbit. Madhavan Nair went on to become ISRO Chairman. After the 1994 and 1996 PSLV flights, Ramakrishnan became the Mission Director of the next four PSLV Continuation flights, all of which were spectacularly successful. 

Thus began the saga of the triumphant PSLV programme of ISRO. When the PSLV-C50 rose majestically from its launch pad at Sriharikota at 3.41 pm on December 17, 2020, and put a communication satellite called CMS-01 precisely into orbit 20 minutes later, it was the 52nd flight of the PSLV. K. Sivan, ISRO Chairman, was delighted with the success and announced that ISRO would soon be launching private satellites under a space reform programme initiated by the Government of India. 

If 50 of these 52 PSLV flights have been successful, a large amount of credit should go to Ramakrishnan. If he had been alive on December 17, 2020, he would have watched the PSLV-C50 flight from the Mission Control Centre at Sriharikota or on a video screen at the VSSC. The mission's success would have gladdened him no end. During the previous PSLV-C49 flight on November 7, 2020, from Sriharikota, I sent him a WhatsApp message on that day, asking him, "Sir, are you in Sriharikota or Thiruvananthapuram? Can I ring you up for a few minutes? Are you free?" Pat came the reply from him, "I am at VSSC. Watching the launch from here."  Long after he retired from ISRO, he was a member of the Launch Authorisation Board of many PSLV and Geo-synchronous Satellite Launch Vehicle (GSLV) flights. 

Ramakrishnan had a way of designing and assembling rockets. It was as if a massive, multi-stage rocket, weighing 640 tonnes, was a toy to him. He played important roles, with his colleagues in the VSSC, in building different versions of them. These versions included the standard PSLV with six strap-on booster motors, "the lean and the hungry" core-alone PSLV without the strap-on motors and the PSLV-XL with extra large and more powerful booster motors. These versions never failed. He was the first rocket technologist in ISRO to use the PSLV to put multiple satellites into orbit. He had a child-like admiration for the late President A.P.J. Abdul Kalam for the latter’s wizardry in rocketry. He once called Kalam “a man of destiny.” He would always appreciate Madhavan Nair for the latter’s acumen in rocketry. 

In an interview to an online publication called, “Precedence”, posted on April 24, 2020, when he was asked about the moments he cherished during his “remarkable journey”, Ramakrishnan had this to say: “Speaking about the moments I cherish, there are several occasions that come to my mind.

“I cannot forget the thrill and the relief we felt on the morning of 18th July 1980 when India became a space-faring nation by successfully orbiting RS-I Rohini satellite on the SLV-3 E2 flight. I feel privileged to have been a part of this pioneering team at ISRO."

“Then, of course, the successful PSLV-D2 launch, accomplished on 15th October 1994 gave a boost to the morale and confidence of the launch vehicle community in ISRO. Nearly half of my life in ISRO, I have spent on the PSLV programme and I am proud of my role in realising this workhorse launcher, providing India an assured access to space."

“I had the privilege of making the PSLV operational through the first four continuation flights, PSLV-C1, C2, C3 and C4. Each of these missions was unique and had some elements such as enhancing the payload, expanding the mission envelope, multi-satellite deployment etc. I cherish my role as the Project Director of these four key flights which stabilised the PSLV as one of the most reliable launch vehicles. In recognition of this contribution, I was honoured by the nation. The hot April day in 2003 when I got the “Padmashri” award from the President of India, I will always remember. What made it remarkable was the fact that I received the awards scroll from the hands of Dr Kalam, who was my first boss at ISRO. When I reported to him at SSTC [SpaceScience and Technology Centre at Thumba] on that sunny morning in August 1972, I had never even dreamt of getting the ‘Padma’ award nor I thought Mr Kalam would one day occupy Rashtrapati Bhavan.”

Indeed, it was a mark of the simple human being that Ramakrishnan was that when an Asianet Malayalam television channel reporter searched him out to inform him that he had been selected to receive the Padmashri award, the reporter found Ramakrishnan standing in the queue to receive the LPG cylinder refill for his residence in Thiruvananthapuram. (There was a scarcity for LPG refill cylinders during that time.)

Ramakrishnan added in his interview to Precedence online publication: “There had been many more such moments to recall such as the successful proving of indigenous cryogenic stages in the GSLV flights, the Mars orbiter reaching the Red Planet after 300 days of sojourn in space etc. However, for me personally, accomplishing the Chandrayaan-1 launch on 22nd October 2008 on the PSLV-C11 is still the most thrilling and satisfying experience to cherish. We had a troubled countdown that was running behind schedule by almost six hours due to repeated leakage problems during the second stage propellant loading. It was beyond midnight and we had only six hours left for the lift-off to take place in the morning and the hope of making the launch was slowly receding. It was then an idea to check the mission calculations with the already loaded quantities was mooted by me so that we can terminate the risky operation at that point and proceed with the remaining countdown tasks and still catch up with the launch window. Quickly the computations to check the missions were done and the above proposal was accepted as feasible to be implemented. The remaining operations were all coordinated in parallel with due precautions and we could make the launch on the dot at the window on that rainy morning of 22nd October 2008. It was a perfect flight and the rest is history. I recall with pride the role played by me as Director (Projects) in accomplishing the above mission.”

The high-water mark of Ramakrishnan’s career was his appointment as the first Project Director of India's ambitious GSLV-Mark III rocket. It is the most powerful and heaviest rocket built by ISRO to this day, standing 44 metres tall and weighing 640 tonnes. It is a three-stage vehicle, with a totally new and indigenously developed cryogenic engine. Ramakrishnan and Somanath formed a formidable team in designing and building the GSLV-MkIII, which is an aerial leviathan. It was no exaggeration when Somanath said the GSLV-MkIII featured "a very elegant architecture." The vehicle is a beauty to behold.  It has had four successful flights in a row. In its fourth mission, the GSLV-Mk III M 1 effortlessly put the Chandrayaan – 2 composite module, weighing 3.8 tonnes, into orbit on July 22, 2019.

An image is forever embedded in my memory. It was October 2002 and I was visiting Ramakrishnan in his office at the VSSC. "Towards Sustained Self-reliance in Accessing Space" announced a huge poster on a wall in his cabin. He had been appointed the first Project Director of the GSLV-MkIII. He was all fired up and rearing to go. Only five months earlier, in May, the Government of India had approved the development of GSLV-MkIII. On the vast campus of the VSSC, by the seashore at Thumba, a small building housed Ramakrishnan's cabin, where the GSLV-MkIII project was taking shape. The massive vehicle, as depicted in the poster, was called "gsLVM3", or launch vehicle Mark 3, India's "Next Generation Launch Vehicle." He was proud to call it "a totally new, powerful animal." 

Fifteen years later on June 5, 2017, when the first developmental vehicle of GSLV-MkIII D1 sped from the second launch pad at Sriharikota and flawlessly put the communication satellite called GSAT-19 into orbit more than 16 minutes later, it was a defining moment for Ramakrishnan, who had retired from ISRO by then and also for A.S. Kiran Kumar, ISRO Chairman, K. Sivan, who was the VSSC Director then and the young Somanath, who had become LPSC Director. It was a remarkable performance for the GSLV-MkIII D1 in its maiden mission with the cryogenic engine on. Earlier, there was a sub-orbital mission of GSLV-Mk III in December 2014.

Dr M. Annadurai, known for his prowess in building a variety of satellites and who earned fame as the key builder of Chandrayaan-1 spacecraft, called Ramakrishnan “a gentleman” and “a composed person.” He added: “Ramakrishnan perfected the PSLV. He made it a real workhorse. Of course, with his knowledge of propulsion systems, he helped us with the LAMs in finetuning them. He helped us in developing the throttleable engines with a thrust of 800 Newtons for Chandrayaan-2’s lander. When their development was going on, he was telling us what to do. He had an all-round expertise in rocketry. He engineered different kinds of propulsion systems and their stages. If these systems are really successful today, his contribution to them was wholesome.”

[LAMS or liquid apogee motors in ISRO’s communication satellites are fired with commands from the ground to take the communication satellites to their final geo-synchronous orbit.]

Ramakrishnan was known for conducting project meetings in a  businesslike manner. Dr Annadurai said, “I have seen the way with which he will approach a problem and give a logical solution to it. Unnecessary discussions will be avoided. Required discussions  will be allowed.”

V.P. Balagangadharan, who retired as Group Head, Technology Transfer and Documentation Group, VSSC, called Ramakrishnan “one of the finest directors of the VSSC.” To work under him in a project was akin “to sitting in front of a formidable teacher.” Mr Balagangadharan said Ramakrishnan would conduct important project meetings in an efficient, businesslike manner. He would stick to the agenda, finishing one subject after another in a systematic manner. While the late S. Srinivasan, who was the VSSC Director, initiated the PSLV project, Madhavan Nair became the Mission Director of the second and third developmental flights of the PSLV. Ramakrishnan took over from Madhavan Nair for the next four PSLV Continuation flights and enabled the PSLV to scale heights, Mr Balagangadharan remembered.

Ramakrishnan grew up in Chennai. He studied in P.S. High School, Mylapore, Chennai. He was a National Science Talent Search Scholar. He did his Pre-University Course in Vivekananda College and graduated in Mechanical Engineering from the College of Engineering, Guindy, in 1970. He earned his M.Tech. in Aeronautics from the Indian Institute of Technology Madras in 1972 with a first rank. He joined the VSSC in August 1972 as a member of the SLV-3 team under the leadership of Abdul Kalam.

Dr Somanath, who was truly sad at the passing away of Ramakrishnan, described him as his “mentor and guru for the past 35 years plus, from the early days of my working in the PSLV project” at the VSSC in the 1980s. Dr Somanath met him for the first time when Ramakrishnan was the PSLV Project Manager and Dr Somanath himself was part of that team, which was responsible for the vehicle assembly. “From that time till the last, I was his subordinate in some way or another. He gave us a lot of freedom to do what we wanted. There was no hindrance from him. We were a young team. He was also in his 30s”, the VSSC Director said.

Generally, when a young team wanted to do new things, there would be opposition to them. “But Ramakrishnan was not like that. He would encourage us to try new approaches. He could take bold decisions,” Dr Somanath said. When Ramakrishnan became the Project Director of the first four PSLV Continuation flights, he took Somanath with him there. “He transferred me. Wherever he went, he took me to that project. So I had a lot of opportunities to learn new things…Management of foreign satellites [which were put into orbit by the PSLVs] happened when I was with him,” the VSSC director said. 

From 2000 to 2002, when Ramakrishnan became the chairman of the committee to write the project report on the GSLV-MK III rocket, Somanath was the committee’s member-secretary. “He wrote the project report and I learnt a lot from him. When the project was approved, he became its Project Director and I became the Project Manager”, Somanath said.

On December 18, 2014, the first launch of the GSLV-Mk III took place although it carried only a dummy cryogenic engine. It put a 3.75-tonne, unmanned crew module called CARE into a sub-orbit at an altitude of 126 km. CARE stands for Crew Module Atmospheric Re-entry Experiment. CARE returned to splashdown about 700 km from Port Blair in the Bay of Bengal and the Indian coast guard personnel retrieved it. The spectacular mission signalled that ISRO could send astronauts into space. It thus became a precursor to India’s Gaganyaan mission or the Human Space Flight Programme. For the Gaganyaan mission, which is slated to take place in 2022, Indian astronauts are already receiving training near Moscow, Russia. 

A couple of years earlier, Ramakrishnan had retired as Director, VSSC. Dr Somanath had become the Project Director of the GSLV-Mk III. Flourishing a golden-hued replica of the GSLV-Mk III, after the sub-orbital flight’s success, Somanath declared, “India has a new launch vehicle now. We have done it again.” S. Unnikrishnan Nair, then Project Director, Human Space Flight Project, called the mission “a grand success” and “a dream come true for us.” Unnikrishnan is now Director, Human Space Flight Centre, Bengaluru. Dr Somanath acknowledged that although Ramakrishnan had retired from ISRO by then, “his support was there for the various phases of the design of the GSLV-Mk III. He was the main reviewer of its design.”

In an unpublished article, Dr Somanath had this to say about Ramakrishnan: “After becoming the Vehicle Director for the PSLV-D3, Ramakrishnan sir became the Mission Director for the PSLV Continuation flights from C1 to C4. He was instrumental in improving the payload capability of the PSLV from 900 kg to 1,500 kg in measured steps.” He did that by increasing the loading of the solid propellants in the PSLV first stage from 125 tonnes to 130 tonnes, that of the liquid second stage from  37.5tonnes to 40 tonnes, by introducing the high-performance third stage engine and many composite structures. As the Project manager in the PSLV project at that time, Dr Somanath was responsible for Vehicle Engineering and Launch Service Management, which Ramakrishnan had created, to handle the activities for the separation systems of the auxiliary satellites from the PSLV in flight. They were all commercial satellites being put into orbit for customers from abroad. Somanath said, “We had our first-time launches of auxiliary satellites, “KitSat” and “DLR-Tubsat” in C2 and “Proba” and “BIRD” satellites in C3. He fully exploited the range of possibilities of the perfectly engineered system of the PSLV, introducing many changes and improvements including the first time launch of Kalpana (Metsat) in geo-synchronous transfer orbit (GTO) in the PSLV-C4. From there, the PSLV leapt into prominence with many missions of repute including Chandrayaan-I and MOM [Mars Orbiter Mission].”

Dr Somanath recalled how Ramakrishnan supported him in designing and developing a new camera system with lighting effects, mounted on the PSLV-C4, to take pictures of the separation of the satellites from the launch vehicle.

Ramakrishnan leaves behind his wife Anuradha, daughter Harini and son Shyam. Harini said her father would often spend “quality time” with his family. He was always available to clarify her or her brother’s doubts in studies.

I will never forget this observation of Ramakrishnan, which he made to me many years ago. He said, “India has an assured access to space. We are self-reliant. We can build any type of launch vehicle. We can build any kind of satellite. We can put any type of satellite in any orbit with our own launch vehicle. We have demonstrated this over the last several years.”