The main objective of the Astro A (Hinotori) mission was the detailed study of solar flares during solar maximum.

Wavelength scanning was achieved by the spacecraft revolution, with an offset pointing of the spin axis with respect to the sun. Investigations of both experiments each had a time resolution of 6 s. In addition, the following investigations were included: three solar flare X-ray monitors that recorded the time profile and spectrum of the X-ray flares in the range of 2 to 20 keV. a solar flare gamma-ray detector for the range 0.2 to 9.0 MeV, a particle detector that monitored electron flux above 100 keV. and plasma probes for the measurement of electron density and temperature.