But the point of interest for me is that both of them played a significant role in Vienna [Images] during my own time in the Austrian capital. In my work in Vienna, I had more to do with Dr Kakodkar and Dr Nair than with my own colleagues in the ministry of external affairs.

The fact that they were highly regarded, personable and purposeful was a factor of extreme importance in my role in Vienna as the permanent representative of India to the United Nations. Their work beyond Vienna may have won them laurels now, but their work in Vienna was also worthy of approbation and emulation.

My assignment to Vienna coincided with Dr Kakodkar's elevation to the chairmanship of the Atomic Energy Commission and I did not deal with any other chairman in the four years that I was in Vienna as the governor of the International Atomic Energy Agency.

I met the previous Chairman, Dr R Chidambaram, in Vienna in his new incarnation as the scientific adviser to the prime minister and as a universally acknowledged authority on nuclear energy, but he did not involve himself in the work of the IAEA Board, which he had once chaired. Dr Kakodkar's scientific knowledge and understanding of Indian interests were to be expected, but his global perspective and diplomatic skills astonished me.

The division of labour between the chairman and governor was that the former would take care of the scientific aspects, while the latter would deal with diplomatic and political issues, but he was as much helpful to me in tackling delicate diplomatic issues as in dealing with the science of the atom.

The very first occasion that I noticed Dr Kakodkar's political sense was at the first dinner I hosted for him to introduce him to my colleagues on the board of governors. In my toast, I spoke about his various accomplishments and mentioned the fact that he was a member of the scientific teams which conducted the tests of 1974 and 1998.

In the process, I must have given the impression that he is the bomb man of India. This would be a great compliment in the national context, but in Vienna, this could convey the wrong message as the emphasis there is on peaceful uses of atomic energy rather than its lethal uses.

In his response, Dr Kakodkar stressed his experience in peaceful uses of the atom rather than the bomb, applying the necessary corrective without contradicting me. I thought that it was a master stroke.

Unlike the chairmen of some other national commissions like those of Pakistan, France [Images], Russia [Images] etc, the Indian chairman does not attend board meetings, where much of the scientific and diplomatic work is done. The director, BARC, is the alternate to the governor, who is traditionally the ambassador.

But inputs from our nuclear scientific community in Mumbai [Images] were crucial for me to respond to the issues before the board. Dr Kakodkar made sure that the flow of material was maintained. On diplomatic issues too I received valuable advice from him and his colleagues.

Our nuclear scientists are generally reticent people because of the nature of the work they do and the sensitivity of the information that they handle. Dr Kakodkar is particularly conscientious in this matter and gives the impression that he is not very forthcoming. Dr Chidambaram, on the other hand, has developed the art of appearing to be open and friendly, while keeping the nation's secrets. But Dr Kakodkar is equally friendly and effusive in small groups where the conversation is more about cricket and music rather than about fission and fusion.

The relationship between the chairman and the governor in Vienna is a delicate one at the best of times and between the best of people and there have been cases in history where the two did not see eye to eye.

One celebrated case was when the government designated the chairman rather than the ambassador to chair the board of governors when it was India's turn to provide the chair. The ambassador rightly insisted on being transferred out of Vienna rather than serve on the board at a lower level. We were on the brink of a similar situation during my time, but our government did not have to choose between the ambassador and the chairman as the US did not want India to hold leadership positions in the IAEA after 1998.

Of course, the Padma Vibhushan awarded to Dr Kakodkar was more on account of the India-US nuclear deal rather than the IAEA. His role in bringing it about has been commented on extensively in the press. The prime minister himself stated that he took the views of Dr Kakodkar into account every time a crucial decision was taken. He virtually had a veto in the decision making process.

Many of his peers in the scientific community, who opposed the deal on various counts, must have put pressure on him to disown the deal. No one may ever know the extent of the role played by him, but it is certain that, without his constructive contribution, the deal would never have come about.

I knew G Madhavan Nair long before he came to Moscow [Images] as the director of the Vikram Sarabhai Space Centre in Trivandrum to participate in the committee on outer space. He was my contemporary at Kerala University, where he did his engineering degree. His entire space career was in Kerala before he became chairman of the Indian Space Research Organisation, ISRO, in Bangalore.

But his international reputation as a space scientist was evident in the committee. The work we began together to get a leadership position for India in the committee fructified only after he became chairman, but his scientific contribution to the work of the committee was well known.

It was far from certain that he would head the organisation when we were in Vienna, but that did not dampen his enthusiasm for space research. I remember him speaking to me about India's lunar mission even at that time.

Chandrayaan [Images] was not a one-time miracle. It came as the culmination of a long and arduous journey, led by eminent scientists and engineers. Nair was involved in it from the early stages and his stewardship gave the whole programme a new life. His incorrigible optimism prompted him to get the necessary investments and his crowning glory came when the Chandrayaan mission became successful and India reached the forefront of space exploration.

He is now dreaming of the day when an Indian will land on the moon in the not too distant future. I am sure that the space committee in Vienna will give him a hero's welcome, if it has not done so already.

Vienna must be proud that the two Padma Vibhushan winners this year are veterans of the city, which has become the home of international cooperation in nuclear energy and outer space. Their experience in Vienna must have given the international perspective to these two essentially home grown Indian scientists.

T P Sreenivasan is a former Indian ambassador to the United Nations, Vienna, and a former governor for India, International Atomic Energy Agency, Vienna.