Bangalore, Aug 2 - In the nine months India's Chandrayaan-1 has been circling the moon everyone connected with it has been awarded, rewarded or interviewed on TV, except the scientist whose pioneering work in liquid propulsion was pivotal to the mission's success. Perhaps it had something to do with the false spying charges under which he was arrested in 1994.

It may seem odd but Nambi Narayanan who introduced the liquid fuel rocket technology in India was ignored not only by the media but also by the Indian Space Research Organisation (ISRO) that he served for over three decades.

In the early 1970s while A.P.J. Abdul Kalam's team worked on solid motors -- that have uses in military missiles -- Narayanan was the one who foresaw the need for liquid fuelled engines for ISRO's future civilian space programmes.

Starting from scratch -- and encouraged by then ISRO chairman Satish Dhawan and his successor U.R. Rao -- Narayanan worked on liquid propellant motors, first building and successfully testing a 600-kg thrust engine in the mid-1970s and moving on to bigger engines.

After nearly two decades of work and with assistance from France he led his team to develop the Vikas engine used today by all ISRO rockets including the Polar Satellite Launch Vehicle (PSLV) that took Chandrayaan-1 to the moon on Oct 22, 2008.

The Vikas engine is employed as the second stage of PSLV and as the second and the four strap-on stages of Geo-Synchronous Satellite Launch Vehicle (GSLV).

While the nation cheered Chandrayaan-1 and the government showered awards on several ISRO scientists, Narayanan's contribution was not mentioned even in passing by ISRO whose future projects to put a man in orbit, or land on the moon, rely on the liquid engines that Narayanan helped develop.

'I am very happy Chandrayaan-1 is a success,' the unassuming scientist told IANS, displaying no grudge against ISRO despite being sidelined. 'I am only sad that not one senior ISRO official acknowledged in public my contribution to the moon mission.'

Narayanan will be happy to know that in private, however, his work is recognised within the ISRO community including its current chairman Madhavan Nair. 'It was Nambi (Narayanan) who got the liquid propulsion test facility established (in Mahendragiri) and he indeed played a key role in Vikas engines used in our rockets,' Nair told IANS.

ISRO sources admit Narayanan would have been projected as one of the heroes of Chandrayaan-1 had he not been falsely accused as a spy by the Kerala police in November 1994 leading to his suspension from his job as head of ISRO's liquid propulsion centre and director of the just launched indigenous cryogenic engine project.