The Indian space programme has the primary goal of promoting and establishing a vibrant space science, technology and applications programme to assist in the overall development of the nation. ISRO has successfully demonstrated its capability to build state-of-the-art remote sensing and communication satellites as well as launch vehicles. This opened up possibilities for modest space-borne astronomical experiments. Studies in Space science and particularly space astronomy began early on in the form of several experimental opportunities. Starting from sounding rockets, balloons and several rocket-borne experiments to study hard X-ray emission from discrete X-ray sources, an X-ray payload was flown onboard Aryabhata, the first Indian satellite, in 1975.

The Indian Cosmic Ray Experiment, Anuradha was launched onboard Space Shuttle Spacelab-3 during 1985. It was designed to measure the ionization states of low energy cosmic rays in near-earth space. The first significant Indian space astronomy instrument was a Gamma Ray Burst (GRB) detector developed for the SROSS series of satellites. Onboard the SROSS- C2 satellite launched in 1994, the experiment (often referred as payload in satellites) detected around sixty GRB events in the 20 keV to 3000 keV range and studied their temporal and spectral properties in the gamma ray band.

GRB detector was followed by the Indian X-ray Astronomy Experiment (IXAE) payload on IRS-P3 satellite launched in 1996.

The success of these astronomy experiments triggered a discussion about a dedicated astronomy satellite, AstroSat. This was planned to be a major astronomical mission which would bring together various scientific institutes and universities and provide much needed inspiration to the young students of the country to undertake careers related to astronomy.

During the same period the experimental activity continued with a Solar X-ray spectrometer (SoXS) which was flown onboard GSAT-2 in 2003. This payload observed the intensity, peak energy and width of spectral line features due to iron atoms in the spectra of several solar bursts.

A low energy gamma-ray spectrometer experiment, RT-2 was flown onboard Russian CORONAS-Photon mission on 30 January 2009 to study hard X-rays from the Sun in the energy range of 15 keV to 150 keV extended to 1 MeV.

Indian X-ray Astronomy Experiment (IXAE)

IXAE is an X-ray astronomy experiment jointly developed by Tata Institute of Fundamental Research, Mumbai and U R Rao Satellite center (URSC, formerly called ISRO Satellite Center), Bangalore to study spectral and temporal characteristics of cosmic X-ray sources. The experiment carried three identical gas filled X-ray proportional counters and one all sky monitor. The experiment was launched on onboard IRS P3 on March 21, 1996.

Observational studies of many bright X-ray binary star systems including X-ray pulsars and stellar mass black hole candidates have been carried out. Studies of mass accretion around neuton star and black hole binaries were some of the major outcomes fromIXAE experiment.

The experiment is highly successful and produced little more than 30 publications and four PhD thesis.