The Defence Research and Development Organisation (DRDO) (IAST: Raksā Anūsandhān Evam Vikās Sangaṭhan) is the premier agency under the Department of Defence Research and Development in Ministry of Defence of the Government of India, charged with the military's research and development, headquartered in Delhi, India. It was formed in 1958 by the merger of the Technical Development Establishment and the Directorate of Technical Development and Production of the Indian Ordnance Factories with the Defence Science Organisation. Subsequently, Defence Research & Development Service (DRDS) was constituted in 1979 as a service of Group 'A' Officers / Scientists directly under the administrative control of Ministry of Defence. With a network of 52 laboratories that are engaged in developing defence technologies covering various fields like aeronautics, armaments, electronics, land combat engineering, life sciences, materials, missiles, and naval systems, DRDO is India's largest and most diverse research organisation. The organisation includes around 5,000 scientists belonging to the DRDS and about 25,000 other subordinate scientific, technical, and supporting personnel. History The DRDO was established in 1958 by combining the Defense Science Organisation and some of the technical development establishments. A separate Department of Defense Research and Development was formed in 1980, which later administered DRDO and its almost 30 laboratories and establishments (there were almost 52 labs before merging). Most of the time, the Defense Research and Development Organisation was treated as if it were a vendor and the Army Headquarters or the Air Force Headquarters were the customers. Because the Army and the Air Force themselves did not have any design or construction responsibility, they tended to treat the designer or Indian industry at par with their corresponding designer in the world market. If they could get a MiG-21 from the world market, they wanted a MiG-21 from DRDO. DRDO started its first major project in surface-to-air missiles (SAM) known as Project Indigo in the 1960s. Indigo was discontinued in later years without achieving full success. Project Indigo led to Project Devil, along with Project Valiant, to develop short-range SAM and ICBM in the 1970s. Project Devil itself led to the later development of the Prithvi missile under the Integrated Guided Missile Development Programme (IGMDP) in the 1980s. IGMDP was an Indian Ministry of Defence programme between the early 1980s and 2007 for the development of a comprehensive range of missiles, including the Agni missile, Prithvi ballistic missile, Akash missile, Trishul missile and Nag