The Indian Space Research Organization (ISRO) was established on August 15, 1969, but the roots of India's space program can be traced back to the early 1920s. Before the formation of ISRO, India's space program was conducted under the guidance of a few scientists and institutions. In this answer, we will discuss what ISRO was known before 1969.
The history of India's space program can be traced back to the early 1920s, when the scientist S.K. Mitra carried out experiments on the ionosphere using ground-based equipment. In the 1940s, the Indian scientist Vikram Sarabhai began advocating for the development of a space program in India. In 1947, India gained independence from British rule, and the newly-formed government focused on developing the country's infrastructure, including science and technology.
In 1950, the Indian National Committee for Space Research (INCOSPAR) was established under the chairmanship of Vikram Sarabhai. The committee was responsible for developing a plan for India's space program, including the launch of sounding rockets for atmospheric research. In 1962, India launched its first sounding rocket from the Thumba Equatorial Rocket Launching Station (TERLS) in Thiruvananthapuram.
In 1963, INCOSPAR was renamed the Indian Space Research Organization (ISRO), and the organization was formally established as a separate entity in 1969. The primary objective of ISRO was to develop a self-reliant space program for India and to use space technology for the country's socioeconomic development.
Before the formation of ISRO, India's space program was primarily focused on atmospheric research using sounding rockets. However, with the establishment of ISRO, India's space program expanded to include the development of satellites, launch vehicles, and other space-related technologies.
ISRO's first major project was the Satellite Instructional Television Experiment (SITE), which was launched in 1975. The project used satellite technology to provide educational television programs to remote areas of India. The project was a success and demonstrated the potential of satellite technology for India's socioeconomic development.
Since then, ISRO has launched a variety of satellites for various applications such as communication, earth observation, navigation, and scientific research. ISRO has also developed a range of launch vehicles, including the Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous Satellite Launch Vehicle (GSLV).
