Kyokko (Exos A) is a satellite designed by JAXA to support International Magnetospheric Study. The spacecraft's main structure was a 0.946-meter-diameter cylinder with shallow, truncated cones attached to both ends. 35 W of solar cells covered the majority of the surface. Two roughly 1.9-meter-long booms protruded from the main body's equator. A permanent magnet was positioned at the tip of each boom to ensure that the spacecraft's center axis was aligned with the nearby geomagnetic field line.

The missions goal was to observing the aurora borealis, researching aurora-related phenomena, and researching the ionosphere and magnetosphere.