Anil Kakodkar, a key protagonist in the controversial Indo-US nuclear deal, will get two more years in the hot seat.
Kakodkar, secretary, Department of Atomic Energy, was due to retire in November.
The government on Thursday decided to change the rules to extend the services of the Atomic Energy secretary and Space Secretary, G Madhavan Nair. The space secretary was due to retire this month-end.
Information and Broadcasting Minister Priya Ranjan Dasmunsi said the amendment will enable the Centre to provide continuity to the two scientists to ensure effective implementation of the plans and programmes of national importance in the two fields.