NEW DELHI: Defence secretary Rajesh Kumar Singh has been given additional charge of the posts of secretary, Department of Defence Research and Development, and chairman of the Defence Research and Development Organisation (DRDO) as the current DRDO chief Samir V Kamat is retiring.Singh will take over the additional responsibilities from May 31 as the Appointments Committee of the Cabinet (ACC) issued the orders on Friday evening.During Kamat’s tenure as DRDO chairman since Aug 2022, the research organisation focused on structural reforms, advancing cutting-edge technologies like quantum computing and stealth unmanned combat aerial vehicles, and accelerating indigenous systems for the armed forces.Kamat pushed for advancements in the electromagnetic aircraft launch system (EMALS), indigenous electric propulsion for warships, and heightened space-based Intelligence, surveillance, and reconnaissance (ISR). His tenure also witnessed the expansion of 15 DRDO industry academia centres of excellence to steer translational research.A 1989-batch IAS officer of the Kerala cadre and the current defence secretary, Rajesh Kumar Singh took over as defence secretary at South Block on Nov 1, 2024. Before assuming the post, he had taken charge as OSD (defence secretary-designate) on Aug 20, 2024. Prior to his appointment as defence secretary, Singh served as Secretary in the Department for Promotion of Industry and Internal Trade from April 24, 2023, to Aug 20, 2024. Before it, Singh had earlier held several key positions, including director (works and urban transport) in the ministry of urban development, commissioner (Lands) in DDA and joint secretary in the ministry of petroleum and natural gas.