The Indian Space Research Organisation (ISRO, Hindi: भारतीय अन्तरिक्ष अनुसंधान संगठन) is the primary body for space research under the control of the Government of India, and one of the leading space research organizations in the world. It was established in its modern form in 1969 as a result of coordinated efforts initiated earlier. Taking into consideration its budget, it is among the most efficient space organizations on the globe.[2] Over the years, ISRO has conducted a variety of operations for both Indian and foreign clients. ISRO's satellite launch capability is mostly provided by indigenous launch vehicles and launch sites. In 2008, ISRO successfully launched its first lunar probe, Chandrayaan-1, while future plans include indigenous development of GSLV, manned space missions, further lunar exploration, and interplanetary probes. ISRO has several field installations as assets, and cooperates with the international community as a part of several bilateral and multilateral agreements.
Modern space research in India is most visibly traced to the activities of scientist S.K. Mitra who conducted a series of experiments leading to the sounding of the ionosphere by application of ground based radio methods in 1920's Calcutta.[3] Later, Indian scientists like C.V. Raman and Meghnad Saha contributed to scientific principles applicable in space sciences.[3] However, it was the period after 1945 which saw important developments being made in coordinated space research in India.[3] Organized space research in India was spearheaded by two scientists: Vikram Sarabhai—founder of the Physical Research Laboratory at Ahmedabad—and Homi Bhabha, who had played a role in the establishment of the Tata Institute of Fundamental Research in 1945.[3] Initial experiments in space sciences included the study of cosmic radiation, high altitude and airborne testing of instruments, deep underground experimentation at the Kolar mines—one of the deepest mining sites in the world — and studies of the upper atmosphere.[4] Studies were carried out at research laboratories, universities, and independent locations.[4][5]

Government support became visible by 1950 when the Department of Atomic Energy (India) was founded with Homi Bhabha as secretary.[5] The Department of Atomic Energy provided funding for space research throughout India.[6] Tests on the Earth's magnetic field—studied in India since the establishment of the observatory at Colaba in 1823—and aspects of meteorology continued to yield valuable information and in 1954, Uttar Pradesh state observatory was established at the foothills of the Himalayas.[5] The Rangpur Observatory was set up in 1957 at Osmania University, Hyderabad.[5] Both these facilities enjoyed the technical support and scientific cooperation of the United States of America.[5] Space research was further encouraged by the technically inclined prime minister of India—Jawaharlal Nehru.[6] In 1957, the Soviet Union successfully launched the Sputnik and opened up possibilities for the rest of the world to conduct a space launch.[6] The Indian National Committee for Space Research (INCOSPAR) was found in 1962 with Vikram Sarabhai as its chairman.[6]

Beginning in the 1960s, close ties with the Soviet Union enabled ISRO rapidly to develop the Indian space program and advance nuclear power in India even after the first nuclear test explosion by India on 18 May 1974 at Pokhran.[7] The death of Homi Bhabha in an air crash on 24 January 1966 came as a blow to the Indian space program.[8] Following Bhabha's passing, Sarabhai was sent to assume Bhabha's place as the chairman of the Atomic Energy Commission and secretary of the Department of Atomic Energy.[8] The 1960s also saw the founding of the Space Science and Technology Centre (SSTC), Experimental Satellite Communication Earth Station (ESCES, 1967), the Sriharikota base, and the Indian Satellite System Project (ISSP).[8] The Indian Space Research Organization in its modern form was created by Vikram Sarabhai in 1969.[8] This body was to take control of all space activities in the Republic of India.[8]