Denied, accused, vindicated: Nisar for the world, redemption for Nambi

India and the US achieved a breakthrough co-operative endeavour with the historic launch of the Nasa-Isro Synthetic Aperture Radar (Nisar) satellite. Costing approximately $1.3 billion, Nisar is the most expensive civilian Earth observation satellite ever constructed and the most audacious collaborative science mission ever embarked upon by the two nations.

The 2,392-kilogram Nisar has been inserted into a sun-synchronous orbit and will take 97 minutes to orbit the Earth. Fitted with advanced radar systems, it will observe the planet day and night, in all weather, with high accuracy.

GSLV'S FLIGHT OF REDEMPTION

What is so impressive about this release is not the satellite itself but the rocket that left it in space. Isro sent Nisar aboard its heavy-lift Geosynchronous Satellite Launch Vehicle, GSLV-F16, to a sun-synchronous orbit.

The cryogenic upper stage of the GSLV is the workhorse of the rocket, a 100% indigenous high-efficiency engine that provides the rocket that final boost into orbit. But the engine is more than a technological milestone.

It is a testament to the strength of India and to the personal redemption of the man who presided over its creation: Nambi Narayanan.

Ironically enough, the very same technology once denied to India was employed to send one of its satellites into space for the very same country that attempted to deny it to it - and by the United States, the very nation that had objected to India's action to acquire cryogenic engine technology, which is now a customer of it.

To grasp the reason why this moment is so important, it is necessary to go back to where the journey had started, three decades prior, when a scientist's passion burst into geopolitics and almost stole everything from him.

THE NAMBI SAGA

By the early 1990s, Isro had decided to move away from the PSLV to the GSLV system. For these heavier rockets, Isro scientists tested three kinds of fuel systems. The first was earth-storable fuels, liquids that are stable in the terrestrial environment, like unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide. These were simpler to handle but less efficient.

The second was semi-cryogenic motors, employing a mixture of liquid oxygen and kerosene. More efficient, but not yet invented. The third, and the most powerful of them all, was cryogenic thrust, with liquid hydrogen and liquid oxygen maintained in very low temperatures.

Technologically challenging as they were, cryogenic engines provided the highest thrust and were best suited for the rocket's second stage. Cryogenics was the option that was most obvious, but most difficult to master.

Cryogenic propulsion uses super-cooled liquid hydrogen and liquid oxygen as the propellants, kept at temperatures as low as –250C. They have extremely high thrust, thus being a must for launching heavy satellites into high orbits. But the very properties that make cryogenic engines so powerful also make them hugely complex. It is not possible to store and manage such super-cooled fuel without high-technology materials. A single leakage of heat would make the fuel evaporate or create pressure imbalances.

Year after year, years would go into designing a working engine, and India's satellite programme could not afford that luxury. With deadlines looming, Isro had to search outside for buying the technology. It was only in the US, Japan, European nations, and Russia where a working cryogenic engine was made at that point.

There were overtures from the United States and the European Union, but both were very costly and technology transfer-free.

Then came Russia's Glavkosmos. In 1990, it presented much more appealing an offer: two cryogenic engines with full technology transfer. To Isro, it was a breakthrough. The contract was signed and a group of eight Indian scientists were deputed to Moscow to start training and co-development.

US BANS INDIA

The United States protested fifteen months later that the agreement was a violation of the Missile Technology Control Regime (MTCR) and levied sanctions. The West was concerned that India would use cryogenic technology to manufacture long-range ballistic missiles.

Under mounting international pressure, Glavkosmos went back on the commitment in 1993. Instead, there was a heavily renegotiated agreement that permitted the supply of seven complete cryogenic engines—but no transfer of technology.

During the same time, there was government approval for a Rs 300 crore project to develop an Indian indigenized cryogenic engine. Its design would be headed by Nambi Narayanan.

Narayanan joined Isro in 1966 as a technical assistant at the Thumba Equatorial Rocket Launching Station. In 1969, he was deputed to Princeton University under a Government of India scholarship and specialized in chemical rocket propulsion. During the 1970s when Isro was dependent solely on solid-fuel technology, Narayanan introduced liquid propulsion to India.

He spearheaded the Vikas engine development that was a pillar of PSLV and GSLV missions. Currently leading the cryogenic engine programme, Narayanan had taken it as his mission to make India independent in space. As the cryogenic project gathered momentum, a shock storm broke out. Nambi Narayanan and his buddy Sasi Kumaran were suddenly arrested in late 1994 on espionage charges. They were suspected of providing sensitive information to Pakistan through two Maldivian women with whom Narayanan had never even met.

The case shocked the country. Narayanan was put through tough questioning. The cryogenic engine programme, already strained, suffered a setback. Morale in Isro was dented, and one of its best engineers was falsely represented.

Last but not least, the case was handed over to the Central Bureau of Investigation (CBI), which discovered nothing at all in favor of the charges. Narayanan was acquitted. Years later, on September 14, 2018, the Supreme Court finally recognized the gross injustice that had befallen him.

NEVER GIVING UP

Isro and Nambi never lost hope, nor did they ever lose the battle for justice.

The early 2000s witnessed several GSLV test flights going wrong. Engines malfunctioned. Rockets underperformed. Missions were totally lost. Western media was prone to mocking India's ambitions as unrealistic and overambitious.

But India did not give up.

The feat was accomplished on January 5, 2014. Isro successfully sent off the GSLV-D5 mission on a 100% indigenous cryogenic upper stage. Not only was it a technological breakthrough; it was a declaration to the world. The same engine that had been denied, sabotaged, and born in adversity today took to orbit the world's premier Earth observation satellite.

For Nambi Narayanan, this mission is a silent redemption. The rocket, which trailed behind once in the shadow of unfounded allegations, now soars smoothly through space with foreign payloads. The man stigmatised as a traitor then is now revered as a father of India's space indigeneity.